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Sample records for strong dpph radical

  1. Evaluation of the radical scavenging activity of a series of synthetic hydroxychalcones towards the DPPH radical

    Directory of Open Access Journals (Sweden)

    STOYAN P. PARUSHEV

    2011-04-01

    Full Text Available Sixteen hydroxychalcones were synthesized in sufficient purity by the Claisen–Schmidt condensation between appropriate acetophenones and aromatic aldehydes. All the compounds were evaluated for their ability to scavenge the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH radical. Important structure–activity relationships were observed that strongly contribute to the knowledge for the design of DPPH radical scavenging chalcones. Relevant theoretical parameters were computed in an attempt to understand and explain the obtained experimental results.

  2. Enhancing production through optimisation of DPPH and radical ...

    African Journals Online (AJOL)

    ... of dry matter for DPPH radical scavenging activity. Methanol had the lowest value (78 mg g-1 dry matter) for polyphenol extracts and 80 mg g-1 for the DPPH radical scavenging activity. The main extract compounds were gallic acid, catechin and epicatechin. Key Words: High density lipids, polyphenol, radical scavenging ...

  3. Characterization and DPPH Radical Scavenging Activity of Gallic ...

    African Journals Online (AJOL)

    Characterization and DPPH Radical Scavenging Activity of Gallic Acid-Lecithin Complex. C Liu, C Chen, H Ma, E Yuan, Q Li. Abstract. Purpose: To investigate the physicochemical properties and DPPH radical scavenging activity of gallic acid–lecithin complex. Methods: The complex of gallic acid with lecithin was prepared ...

  4. Characterization and DPPH Radical Scavenging Activity of Gallic ...

    African Journals Online (AJOL)

    infrared spectrometry (IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and x-ray diffractometry (XRD). Antioxidant activity was examined by 1-diphenyl-2-picrylhydrazyl. (DPPH) radical scavenging assay. Results: The UV and IR spectra of the complex showed an additive effect of gallic acid ...

  5. DPPH and oxygen free radicals as pro-oxidant of biomolecules.

    Science.gov (United States)

    Letelier, María Eugenia; Molina-Berríos, Alfredo; Cortés-Troncoso, Juan; Jara-Sandoval, José; Holst, Marianne; Palma, Karina; Montoya, Margarita; Miranda, Dante; González-Lira, Víctor

    2008-03-01

    Numerous investigations exist about the alterations that oxygen free radicals can provoke on biomolecules; these modifications can be prevented and/or reversed by different antioxidants agents. On the other hand, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), a stable nitrogen synthetic radical, is used to evaluate the antioxidant capacity of medicinal herbal products; however, the structural changes that this radical provoke on the herbal active principles are not clear yet. In this work, we compared the redox reactivity of oxygen free radicals and DPPH radical on phospholipids and protein thiol groups present in rat liver microsomes. Cu2+/ascorbate was used as generator system of oxygen free radical and as antioxidant, an extract of Buddleja globosa's leaves. Cu2+/ascorbate provoked microsomal lipid peroxidation, microsomal thiols oxidation and oxygen consumption; all of these phenomena were inhibited by B. globosa extract. On the other hand, DPPH was bleached in different extension by the herbal extract and phosphatidyl choline; beside, DPPH decreased microsomal thiols content, but this phenomenon were not prevented by the herbal extract. Furthermore, DPPH did not induce oxygen consumption and neither modified the oxygen consumption induced by Cu2+/ascorbate. Distinct redox mechanisms may explain the differences between the reactivity of DPPH and oxygen free radicals on biomolecules, which is discussed.

  6. Free radical scavenging (DPPH) potential in nine Mentha species.

    Science.gov (United States)

    Ahmad, Nisar; Fazal, Hina; Ahmad, Iftikhar; Abbasi, Bilal Haider

    2012-02-01

    Mentha species are used in every day life in various food items. These species produce valuable secondary metabolites that scavenge toxic free radicals. Toxic free radicals can cause different diseases in the human body. In the present study free radical scavenging potential (1,1-diphenyl-2-picrylhydrazyl scavenging activity) in nine Mentha species were investigated to evaluate and explore new potential sources for natural antioxidants. The activity was performed after different time intervals with incubation period of 30 minutes. The methanolic extracts revealed that significantly higher activity (82%) was observed in Mentha suaveolens, followed by Mentha longifolia (79%), Mentha officinalis (76%) and Mentha piperita, Mentha pulegium, Mentha royleana (75%), respectively. Significantly same activity was observed in Mentha arvensis and Mentha spicata. Lower activity was observed in Mentha citrata (64%). The present study revealed that these species can be used as natural antioxidants.

  7. Screening of various botanical extracts for antioxidant activity using DPPH free radical method.

    Science.gov (United States)

    Waqas, Muhammad Khurram; Saqib, Najam-Us; Rashid, Saeed-Ur; Shah, Pervaiz Akhtar; Akhtar, Naveed; Murtaza, Ghulam

    2013-01-01

    Aiming at the exploration of herbal use by society, crude extracts of the seeds of some commonly used medicinal plants (Vitis vinifera, Tamarindus indica and Glycin max) were screened for their free radical scavenging properties using ascorbic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The overall antioxidant activity of grape seeds (Vitis vinifera) was the strongest, followed in descending order by soybean (Glycin max) and tamarind (Tamarindus indica). The seeds extract of Vitis vinifera, Glycin max and Tamarindus indica showed 85.61%, 83.45% and 79.26%, DPPH scavenging activity respectively.

  8. Structural evidence for the DPPH radical-scavenging mechanism of 2-O-α-d-glucopyranosyl-l-ascorbic acid.

    Science.gov (United States)

    Tai, Akihiro; Iomori, Atsuko; Ito, Hideyuki

    2017-10-15

    2-O-α-d-Glucopyranosyl-l-ascorbic acid (AA-2G) exhibits biological activities after enzymatic hydrolysis to ascorbic acid (AA) by α-glucosidase. We have found that AA-2G per se exerted radical-scavenging activity toward 1,1-diphenyl-2-picrylhydrazyl radical (DPPH radical). The radical-scavenging property of AA-2G was greatly different from that of AA; that is, the reaction rate with DPPH radical of AA-2G was far slower than that of AA, but the long-lasting radical-scavenging ability per one molecule of AA-2G was superior to that of AA. We purified key intermediates for the characteristic radical-scavenging reaction of AA-2G and carried out time-course studies of the radical-scavenging reactions of the intermediates, AA-2G and AA to determine both the reaction rate and stoichiometry of AA-2G with DPPH radical. One mole of AA-2G quenched 2.7mol of DPPH radical over a period of 120min, while one mole of AA quenched 1.9mol of the radical. The high reaction stoichiometry of AA-2G against DPPH radical was associated with adduct formation of AA-2G with DPPH radical. The radical-scavenging reaction mechanism of AA-2G consists of the following three steps: (1) At an early stage of the reaction, AA-2G scavenged DPPH radical to generate AA-2G radical, (2) AA-2G radical immediately reacted with an additional DPPH radical to give two types of AA-2G-DPPH adducts and (3) AA-2G-DPPH adducts slowly quenched the other DPPH radical to generate several reaction products. Our results suggest the practical value of AA-2G, even before being converted into AA, as a beneficial antioxidant in food and cosmetic applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Experimental and theoretical study on DPPH radical scavenging mechanism of some chalcone quinoline derivatives

    Science.gov (United States)

    Hamlaoui, Ikram; Bencheraiet, Reguia; Bensegueni, Rafik; Bencharif, Mustapha

    2018-03-01

    In this study, the antioxidant capacity of three chalcone derivatives was evaluated by DPPH free radical scavenging. Experimental data showed low antioxidant activity (IC50±SD) of these molecules in comparison with BHT. The mechanism of DPPH radical scavenging elucidated by means of density functional theory (DFT) calculations. The tested compounds and their corresponding radicals and anions were optimized using B3LYP functional with 6-31G (d,p) basis set in the gas phase. The C-PCM model was used to perform solvent medium calculations. On the basis of theoretical calculations, it was shown that HAT mechanism was predominant in the gas phase, whereas SET-PT and SPLET mechanisms were favored in the presence of the solvent. Moreover, the HOMO orbitals and spin density distribution was evaluated to predict the probable sites for free radical attack.

  10. Batch-injection analysis with amperometric detection of the DPPH radical for evaluation of antioxidant capacity.

    Science.gov (United States)

    Oliveira, Gracy K F; Tormin, Thiago F; Sousa, Raquel M F; de Oliveira, Alberto; de Morais, Sérgio A L; Richter, Eduardo M; Munoz, Rodrigo A A

    2016-02-01

    This work proposes the application of batch-injection analysis with amperometric detection to determine the antioxidant capacity of real samples based on the measurement of DPPH radical consumption. The efficient concentration or EC50 value corresponds to the concentration of sample or standard required to scavenge 50% DPPH radicals. For the accurate determination of EC50, samples were incubated with DPPH radical for 1h because many polyphenolic compounds typically found in plants and responsible for the antioxidant activity exhibit slow kinetics. The BIA system with amperometric detection using a glassy-carbon electrode presented high precision (RSD = 0.7%, n = 12), low detection limit (1 μmol L(-1)) and selective detection of DPPH (free of interferences from antioxidants). These contributed to low detection limits for the antioxidant (0.015 and 0.19 μmol L(-1) for gallic acid and butylated hydroxytoluene, respectively). Moreover, BIA methods show great promise for portable analysis because battery-powered instrumentation (electronic micropipette and potentiostats) is commercially available. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Extracts and Constituents of Rubus chingii with 1,1-Diphenyl-2-picrylhydrazyl (DPPH Free Radical Scavenging Activity

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    Hsiou-Yu Ding

    2011-06-01

    Full Text Available The 1,1-diphenyl-2-picrylhydrazyl (DPPH free radical scavenging activity of the fruits of Rubus chingii was studied in vitro. Ethanolic extract, ethyl acetate and n-butanol fractions from dried R. chingii fruits revealed strong DPPH free radical scavenging activity with IC50 values of 17.9, 3.4 and 4.0 µg/mL, respectively. The ethyl acetate and n-butanol fractions were further purified by a combination of silica gel chromatography, Lobar RP-8 chromatography, and high-pressure liquid chromatography (HPLC. Nine compounds were isolated, where methyl (3-hydroxy-2-oxo-2,3-dihydroindol-3-yl-acetate (2, vanillic acid (5, kaempferol (7, and tiliroside (9 showed stronger DPPH free radical scavenging activity than that of ascorbic acid (131.8 µM with IC50 values of 45.2, 34.9, 78.5, and 13.7 µM, respectively. In addition, rubusine (1 is a new compound discovered in the present study and methyl (3-hydroxy-2-oxo-2,3-dihydroindol-3-yl-acetate (2, methyl dioxindole-3-acetate (3, and 2-oxo-1,2-dihydroquinoline-4-carboxylic acid (4 were isolated from the fruits for the first time.

  12. Dihydronaflavonols from the leaves of Derris urucu (Leguminosae): structural elucidation and DPPH radical-scavenging activity

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, Livia T.; Silva, Geilson A. da; Ferreira, Malisson; Silva, Milton N. da; Santos, Alberdan S.; Arruda, Alberto C.; Guilhon, Gisele M.S.P.; Santos, Lourivaldo S.; Arruda, Mara Silvia P. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais. Programa de Pos-Graduacao em Quimica], e-mail: mspa@ufpa.br; Borges, Rosilvaldo dos Santos [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Fac. de Farmacia. Inst. de Ciencias

    2009-07-01

    Derris urucu is an Amazonian plant with insecticide and ichthyotoxic properties. Studies with this species show the presence of flavonoids, mainly rotenoids, as well as stilbenes. The ethanol extract of the leaves of Derris urucu (Leguminosae) afforded three new dihydroflavonols named urucuol A (1), B (2) and C (3), and the dihydroflavonol isotirumalin (4). Their structures were elucidated by extensive analysis of 1D and 2D NMR, UV and IR spectra and MS data and comparison with literature data. The isolated compounds (1-4) were evaluated for DPPH radical scavenging activity and showed a relatively lower antioxidant ability compared to the commercial antioxidant trans-resveratrol. (author)

  13. Antioxidant activities of traditional plants in Sri Lanka by DPPH free radical-scavenging assay

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    Kotaro Hara

    2018-04-01

    Full Text Available This article describes free radical-scavenging activities of extracts of several plants harvested in Sri Lanka through the 1,1-diphenyl-2-picrylhydrazyl (DPPH assay. These plants have traditionally been used in the indigenous systems of medicine in Sri Lanka, such as Ayurveda, as described below. (English name, “local name in Sri Lanka,” (scientific name.bougainvillea plant, “bouganvilla,” (Bougainvillea grabla, purple fruited pea eggplant,”welthibbatu,” (Solanum trilobatum [1], country borage plant, “kapparawalliya,” (Plectranthus amboinicus [2], malabar nut plant, “adhatoda,” (Justicia adhatoda [3], long pepper plant,”thippili,” (Piper longum [4], holy basil plant, “maduruthala,” (Ocimum tenuiflorum [5], air plant, “akkapana,” (Kalanchoe pinnata [6], plumed cockscomb plant, “kiri-henda,” (Celosia argentea [7], neem plant,”kohomba,” (Azadirachta indica [8], balipoovu plant, “polpala,” (Aerva lanata [9], balloon-vine plant, “wel penera,” (Cardiospermum halicacabum [10], emblic myrobalan plant, “nelli,” (Phyllanthus emblica [11], indian copperleaf plant, “kuppameniya,” (Acalypha indica [12], spreading hogweed plant, “pita sudu sarana,” (Boerhavia diffusa [13], curry leaf plant, “karapincha,” (Murraya koenigii [14], indian pennywort plant, “gotukola,” (Centera asiatica [15], jewish plum plant, “ambarella,”(Spondias dulcis [16]. Keywords: Antioxidative activity, DPPH radical-scavenging assay, Traditional plant, Medical herb

  14. Indoline Amide Glucosides from Portulaca oleracea: Isolation, Structure, and DPPH Radical Scavenging Activity.

    Science.gov (United States)

    Jiao, Ze-Zhao; Yue, Su; Sun, Hong-Xiang; Jin, Tian-Yun; Wang, Hai-Na; Zhu, Rong-Xiu; Xiang, Lan

    2015-11-25

    A polyamide column chromatography method using an aqueous ammonia mobile phase was developed for large-scale accumulation of water-soluble indoline amide glucosides from a medicinal plant, Portulaca oleracea. Ten new [oleraceins H, I, K, L, N, O, P, Q, R, S (1-10)] and four known [oleraceins A-D (11-14)] indoline amide glucosides were further purified and structurally characterized by various chromatographic and spectroscopic methods. The DPPH radical scavenging activities of oleraceins K (5) and L (6), with EC50 values of 15.30 and 16.13 μM, respectively, were twice that of a natural antioxidant, vitamin C; the EC50 values of the 12 other indoline amides, which ranged from 29.05 to 43.52 μM, were similar to that of vitamin C. Structure-activity relationships indicated that the DPPH radical scavenging activities of these indoline amides correlate with the numbers and positions of the phenolic hydroxy groups.

  15. Synthesis of heterocyclic chalcone derivatives and their radical scavenging ability toward 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Kijun; Kim, Hoseok; Kim, Beomtae [Research Center of Bioactive Materials, Hwaseong (Korea, Republic of); Han, Incheol [Chonbuk National Univ., Jeonju (Korea, Republic of)

    2012-04-15

    A series of heterocyclic chalcone derivatives bearing heterocycles such as thiophene or furan ring as an isostere of benzene ring were carefully prepared, and the influence of heterocycles on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities was systematically investigated. Structure-activity relationships (SAR) analysis showed that the activities of thiophene ring-containing chalcones were higher than those of furan ring containing chalcones, and the presence of methyl substituent of heterocyclic ring distinctly affected the activities compared with non-substituted heterocycles in an opposite manner, with the 4'-methyl group of thiophene ring increasing activity and the 3'-methyl group of the furan ring decreasing activity. The distinct isosteric effect of heterocycles (i.e., thiophene or furan ring) on radical scavenging activities of heterocyclic chalcones was distinctly demonstrated in our work.

  16. The ability of Abelmoschus manihot L. leaf extract in scavenging of free radical DPPH and total flavonoid determination

    Science.gov (United States)

    Sudewi, S.; Lolo, W. A.; Warongan, M.; Rifai, Y.; Rante, H.

    2017-11-01

    Abelmoschus manihot L. has reported to have flavonoids content. This study aims were to determine the ability of A. manihot extract in counteracting free radical DPPH and determine the content of total flavonoids. A. manihot leaf was taken from 2 regions in North Sulawesi, namely Tomohon and Kotamobagu. The maceration was carried out to extract the active compound in a 96% ethanol solvent. Free radical scavenging analysis was carried out by DPPH and determination of its total flavonoid in the extract was measured using spectrophotometri method. The results showed that A. manihot extract from Tomohon and Kotamobagu could counteract free radical of DPPH with value of free radical activity of 88.151 and 88.801 %, respectively. A. manihot leaf from Kotamobagu has higher total flavonoids content 61.763 mg/g compare to Tomohon 46.679 mg/g which presented as quercetin. A. manihot has antioxidant activity.

  17. New mono-ether of glycerol and triterpenes with DPPH radical scavenging activity from Cameroonian propolis.

    Science.gov (United States)

    Talla, Emmanuel; Tamfu, Alfred Ngenge; Gade, Isaac Sylvère; Yanda, Lambert; Mbafor, Joseph Tanyi; Laurent, Sophie; Elst, Luce Vander; Popova, Milena; Bankova, Vassya

    2017-06-01

    The extracts of some propolis samples were analysed by GC-MS and then purified by column chromatography. The latter led to the isolation of a new mono-ether of glycerol, 1'-O-eicosanyl glycerol and a new triterpene, methyl-3β,27-dihydroxycycloart-24-en-26-oate together with known triterpenoids namely betulin, 3β-hydroxylanostan-9,24-dien-21-oic acid, mangiferonic acid, a mixture of ambolic acid and β-sitosterol, 3β-hydroxycycloartan-12,24(25)-diene and 27-hydroxymangiferonic acid. The DPPH radical scavenging potential of some extracts and compounds were measured. The radical scavenging activity varied from Hexane extract of Foumban propolis (IC 50  = 5.6 mg/mL) to Methanol extract of Foumban propolis (IC 50  = 1.07 mg/mL) for the extracts and from 3β-hydroxylanostan-9,24-dien-21-oic acid (IC 50  = 1.22 mg/mL) to 1'-O-eicosanyl glycerol (IC 50  = 0.93 mg/mL) for the compounds. Activities of samples were moderate as they remained closer to those of the standard antioxidants Gallic acid (IC 50  = 0.30 mg/mL) and vitamin C (IC 50  = 0.80 mg/mL), especially 1'-O-eicosanyl glycerol, the most active compound.

  18. Kinetic behaviour of DPPH radical scavenging activity of tomato waste extracts

    Directory of Open Access Journals (Sweden)

    Ćetković Gordana S.

    2012-01-01

    Full Text Available The kinetic behaviour of tomato waste extracts (obtained from six genotypes and standard antioxidant compounds (ascorbic and caffeic acid were investigated using 2,2-diphenyl-1-picrylhydrazyl radical test. Based on the time needed for the reaction to reach steady state, the investigated extracts show very slow (steady state ≥ 180 min antiradical behaviour, ascorbic acid act as rapid antioxidant (steady state < 5min while caffeic acid is rapidintermediate antioxidant (5 min < steady state < 20 min. The efficient concentrations at different kinetic times EC50,t were determined for all extracts, ascorbic and caffeic acid. EC50,t was used as a parameter to screen and compare antiradical activities of food extracts with slow kinetic action. Irrespective of the time considered, the comparison of the EC50,t for extracts showed that the DPPH radicals scavenging activity of extracts decreased in the order of O2 > Knjaz > Bačka > Saint Pierre > Rutgers > Novosadski niski. Tomato waste extracts showed very slow kinetic action, which is probably result of the different kinetic bevaviour of phenolic compounds, present in tomato waste, as well as other antioxidants (vitamins, carotenoids etc.

  19. Antioxidant activities of traditional plants in Sri Lanka by DPPH free radical-scavenging assay.

    Science.gov (United States)

    Hara, Kotaro; Someya, Takao; Sano, Katsura; Sagane, Yoshimasa; Watanabe, Toshihiro; Wijesekara, R G S

    2018-04-01

    This article describes free radical-scavenging activities of extracts of several plants harvested in Sri Lanka through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. These plants have traditionally been used in the indigenous systems of medicine in Sri Lanka, such as Ayurveda, as described below. (English name, "local name in Sri Lanka," (scientific name)). bougainvillea plant, "bouganvilla," ( Bougainvillea grabla ), purple fruited pea eggplant,"welthibbatu," ( Solanum trilobatum ) [1], country borage plant, "kapparawalliya," ( Plectranthus amboinicus ) [2], malabar nut plant, "adhatoda," ( Justicia adhatoda ) [3], long pepper plant,"thippili," ( Piper longum ) [4], holy basil plant, "maduruthala," ( Ocimum tenuiflorum ) [5], air plant, "akkapana," ( Kalanchoe pinnata ) [6], plumed cockscomb plant, "kiri-henda," ( Celosia argentea ) [7], neem plant,"kohomba," ( Azadirachta indica ) [8], balipoovu plant, "polpala," ( Aerva lanata ) [9], balloon-vine plant, "wel penera," ( Cardiospermum halicacabum ) [10], emblic myrobalan plant, "nelli," ( Phyllanthus emblica ) [11], indian copperleaf plant, "kuppameniya," ( Acalypha indica ) [12], spreading hogweed plant, "pita sudu sarana," ( Boerhavia diffusa ) [13], curry leaf plant, "karapincha," ( Murraya koenigii ) [14], indian pennywort plant, "gotukola," ( Centera asiatica ) [15], jewish plum plant, "ambarella,"( Spondias dulcis ) [16].

  20. Alaternin, cassiaside and rubrofusarin gentiobioside, radical scavenging principles from the seeds of Cassia tora on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.

    Science.gov (United States)

    Choi, J S; Lee, H J; Kang, S S

    1994-12-01

    Radical scavenging principles on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical were isolated from the seeds of Cassia tora L. Assignments of the 1H- and 13C-NMR data showed the active components to be an anthraquinone, alaternin and two naphthopyrone glycosides, nor-rubrofusarin-6-beta-D-glucoside(cassiaside) and rubrofusarin-6- -D-gentiobioside. Alaternin showed more potent radical scavenging effect than the others.

  1. Photochemical reaction of triplet 9,10-anthraquinone with ethylbenzene in the presence of DPPH as a radical trapping agent

    International Nuclear Information System (INIS)

    Moger, G.

    1983-01-01

    DPPH was used as a scavenger of α-phenyl-ethyl radicals produced in the photochemical reaction between triplet anthraquinone (Qsup(T)) and ethylbenzene (RH 2 ) in benzene solutions. The rate constant ratio ksub(2)/ksub(-1) was determined from the measurements of the quantum yield of scavenging against (RH 2 ) and found to be (0.49+-0.015) M at 25 deg C. (author)

  2. The elevation effect on water-soluble polysaccharides and DPPH free radical scavenging activity of Ganoderma lucidum K

    Science.gov (United States)

    Darsih, C.; Apriyana, W.; Nur Hayati, S.; Taufika Rosyida, V.; Hernawan; Dewi Poeloengasih, C.

    2017-02-01

    Water soluble polysaccharide is one of the important phytochemical in Ganoderma lucidum K. Phytochemicals in the plants, microorganisms, and plants were affected by internal and external factors. The objective of the research was to evaluate the effect of elevation on the water-soluble polysaccharides and its DPPH radical scavenging activity. We found that the water-polysaccharides in mushroom from Godean (elevation Ganoderma lucidum K from Godean (IC50 11.5 ± 0.29 mg/mL) higher than Kaliurang (IC50 14.4 ± 0.27%).

  3. Identification of Free Radical Scavengers from Brazilian Green Propolis Using Off-Line HPLC-DPPH Assay and LC-MS.

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    Zhang, Cuiping; Shen, Xiaoge; Chen, Jiawei; Jiang, Xiasen; Hu, FuLiang

    2017-07-01

    Brazilian green propolis is known as an appreciable natural antioxidant with abundant polyphenolic compounds. For quality control, a fingerprint-efficacy study of Brazilian green propolis was carried out in this work. Chemical fingerprints of Brazilian green propolis from 22 different sources were determined by HPLC and investigated by similarity analysis. The fingerprint-efficacy relationships between chemical fingerprint and DPPH radical-scavenging activity were established. The results showed that 14 characteristic common peaks were identified, and 9 compounds were discovered with free radical-scavenging activities. Caffeoylquinic acids and artepillin C might be the major effective components for quality control of Brazilian green propolis due to their specificity and strong antioxidant activity. This study provides new markers for the quality assessment of Brazilian green propolis and its derived products. © 2017 Institute of Food Technologists®.

  4. Evaluation of antioxidant activity of Ruta graveolens L. extract on inhibition of lipid peroxidation and DPPH radicals and the effects of some external factors on plant extract's potency.

    Directory of Open Access Journals (Sweden)

    S. Mohammadi- Motamed

    2014-01-01

    Full Text Available The antioxidant properties of Ruta graveolens L. were evaluated by two different methods; free radical scavenging using DPPH and inhibition of lipid peroxidation by the ferric thiocyanate method. The IC50 value of the methanol extract in DPPH inhibition was 200.5 μg/mL which was acceptable in comparison with BHT (41.8 μg/mL. In thiocyanate method, the plant extract demonstrated activity as much as BHT in prevention of lipid peroxidation. Increasing the temperature during extraction, significantly decreased the extract power in inhibition of DPPH radicals. The storage time and temperature had no effect on lipid peroxidation inhibition.

  5. Determination of free radical scavenging activity from aqueous extract of Curcuma mangga by DPPH method

    Science.gov (United States)

    Indis, N. A.; Kurniawan, F.

    2016-04-01

    Curcuma mangga (mango ginger) belongs to the family of Zingiberaceae. The rhizome of C. mangga are morphologically similar to ginger (Zingiber officinale) with a little mango flavour. C. mangga can growth in tropical areas and easy found in Indonesia. The rhizomes of C. mangga were washed and cut into the small piece, then drying at room temperature for 6 days, and then grinded until get the powder of C. mangga. The powder of C. mangga was extracted with deminerahzed water by maceration for 6 hours. C. mangga extract was analysed with FTIR spectrophotometer to determine its functional groups. C. mangga extract was diluted at various of concentration (5, 10, 25, 50, 100, 250, 500 mg/L) using deminerahzed water. C. mangga extracts were tested the antioxidant activity using 0.002% DPPH at 517nm with UV-Vis spectrophotometer, and the IC50 value of C. mangga extract is 212.70 mg/L.

  6. Determination of free radical scavenging activity from aqueous extract of Curcuma mangga by DPPH method

    International Nuclear Information System (INIS)

    Indis, N A; Kurniawan, F

    2016-01-01

    Curcuma mangga (mango ginger) belongs to the family of Zingiberaceae. The rhizome of C. mangga are morphologically similar to ginger (Zingiber officinale) with a little mango flavour. C. mangga can growth in tropical areas and easy found in Indonesia. The rhizomes of C. mangga were washed and cut into the small piece, then drying at room temperature for 6 days, and then grinded until get the powder of C. mangga. The powder of C. mangga was extracted with deminerahzed water by maceration for 6 hours. C. mangga extract was analysed with FTIR spectrophotometer to determine its functional groups. C. mangga extract was diluted at various of concentration (5, 10, 25, 50, 100, 250, 500 mg/L) using deminerahzed water. C. mangga extracts were tested the antioxidant activity using 0.002% DPPH at 517nm with UV-Vis spectrophotometer, and the IC 50 value of C. mangga extract is 212.70 mg/L. (paper)

  7. DPPH radical scavenging and xanthine oxidase inhibitory activity of Terminalia macroptera leaves.

    Science.gov (United States)

    Pham, Anh Thu; Malterud, Karl Egil; Paulsen, Berit Smestad; Diallo, Drissa; Wangensteen, Helle

    2011-08-01

    From a methanol extract of the leaves of the Malian medicinal tree Terminalia macroptera, cis-polyisoprene (1), chebulic acid trimethyl ester (2), methyl gallate (3), shikimic acid (4), corilagin (5), rutin (6), narcissin (7), chebulagic acid (8) and chebulinic acid (9), were isolated. Cispolyisoprene (1) was the major non-polar constituent. The novel compound 2 showed high radical scavenging activity (IC50 4.7 microg/mL), but was inactive as xanthine oxidase inhibitor. The major substituent of the crude extract, substance 5, showed a high radical scavenger effect (IC50 2.7 microg/mL) and weak xanthine oxidase inhibition (IC50 ca 105 microg/mL). The antioxidant and radical scavenging effects of some of the substances identified in this study may to some extent explain the medical use of this tree in West Africa.

  8. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum

    Directory of Open Access Journals (Sweden)

    Sohail Ahmad

    2016-01-01

    Full Text Available The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm. Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25–225 μg/mL. Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines.

  9. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum.

    Science.gov (United States)

    Ahmad, Sohail; AbdEl-Salam, Naser M; Ullah, Riaz

    2016-01-01

    The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25-225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines.

  10. Study On DPPH Free Radical - Scavenging Activity Of Antioxidant Compounds In Plants Composing BIN-5 Biological Active Preparation

    Directory of Open Access Journals (Sweden)

    Purevjav Urjintseren

    2015-08-01

    Full Text Available Recently there has been common trend among people to refuse from food and medications produced via synthetic method but try to consume natural products as much as possible instead. In this regard wild berries and medicinal plants are considered to be highly essential for human health as these kinds of plants serve as rich sources of biological active substances-phenol compounds. As a result of conducting research on source and spread of herbs which are commonly used as anti-diabetic medication we have developed a technological method to extract preparations from medicinal herbs such as Peony Paeonia lactiflora Pall Dandelion Taraxacum officinalis Wigg. Huckleberry Vaccinium myrtillus L Blueberry Vaccinium uliginosum L Cranberry Vaccinium vitisidaea L and Stinging nettles Urtica dioica accordingly studied chemical composition and antioxidant activity and conducted pharmacological study. With the use of Folin Denis amp Folin Ciocalteu reagent methodit was determined that the content of polyphenol compounds was 4.14-5.17 and 27.5 101.5mgml. The study was also aimed to investigate DPPH free radical-scavenging activity in connection with term temperature and concentration to identify the most rational technological procedure. As a result of study it was identified that free radical-scavenging activity of herbs selected for the study was generally estimated at 564.25-1750.00 mcgml whereas antioxidant activity of solvents with 2-10 mgml concentration was 417.20-1750.00 mcg ml respectively. This shows that such activity is dependent on concentration. However in temperature of 30 1000amp1057 degrees their activity has slowly been decreased by 1750 mcgml 476.7mcgml depending on temperature. Regarding the stinging nettles the activity was grown directly dependent from temperature. DPHH free radical-scavenging activity was gradually increased in 1-10 minutes but was relatively stable and active in 11-16 minutes.

  11. Free Radical Scavenging Fingerprints of Selected Aromatic and Medicinal Tunisian Plants Assessed by Means of TLC-DPPH(•) Test and Image Processing.

    Science.gov (United States)

    El Euch, Salma Kammoun; Cieśla, Łukasz; Bouzouita, Nabiha

    2014-01-01

    Aqueous-methanol extracts prepared from 10 Tunisian plant species were analyzed for the presence of potent direct antioxidants. The analyzed species included: Anacyclus clavatus Desf., Erica multiflora L., Cistus salvifolius L., Centaurium erythraea Rafn., Marrubium vulgare L., Lavandula stoechas L., Artemisia campestris L., Origanum majorana L., Salvia officinalis L., and Pistacia lentiscus L. All the extracts were chromatographed on the RP18 W plates with methanol-water-acetic acid (48 + 47 + 5, v/v/v) mobile phase. Upon completion of the chromatographic development and the drying step, the plates were stained with a chloroform solution of 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH(•)). An image processing protocol, with use of Sorbfil TLC Videodensitometer, was applied to quantitatively measure the activity of polyphenols and to screen complex samples for the presence of free radical scavengers. The activity of the individual compounds was compared with that of rutin, used as a standard. The TLC-DPPH(•) test showed that C. salvifolius had the most potent antioxidant activity, as it possessed the highest activity coefficient (calculated as the sum of the areas under the peaks of all active compounds/area under peak of rutin). The proposed procedure may be used to differentiate potent chain-breaking antioxidants and compounds propagating radical chain reactions.

  12. Pitfalls of using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay to assess the radical scavenging activity of peptides: Its susceptibility to interference and low reactivity towards peptides.

    Science.gov (United States)

    Zheng, Lin; Lin, Lianzhu; Su, Guowan; Zhao, Qiangzhong; Zhao, Mouming

    2015-10-01

    DPPH assay is widely used to evaluate the radical scavenging activities of peptides. Effects of pH and buffers on the stability of DPPH• and its reduced product (DPPHH) in the ethanol-buffer solution were investigated in this study and the reactivity of DPPH• towards several dipeptides was compared to that of 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS• + ) and the peroxyl radicals in oxygen radical absorbance capacity (ORAC) assay. Results showed that the deprotonation of DPPHH under basic condition could interfere with the spectrophotometric measurement at 515-525nm. It was suggested that the reaction mixture be maintained at a final pH range of 5.0-6.5 in 1:1 ethanol-acetate/citrate buffer medium when evaluating the activities of peptides. Additionally, among tested dipeptides, only Cys-containing dipeptides displayed DPPH• scavenging activity with 0.14-0.28μmol TE (Trolox equivalent)/μmol, while Tyr/Trp-containing dipeptides with high reactivity towards ABTS• + and peroxyl radicals were inert to DPPH• with TE values less than 0.02. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Phytochemical screening and antioxidant activity of ethanolic extract and ethyl acetate fraction from basil leaf (Ocimum basilicum L.) by DPPH radical scavenging method

    Science.gov (United States)

    Warsi; Sholichah, A. R.

    2017-11-01

    Basil leaf (Ocimum basilicum L.) contains various compounds such as flavonoid, alkaloid, phenol and essential oil, so it needs to be fractionated to find out the flavonoid compound with the greatest potential as an antioxidant. This research was aimed to know the chemical compound, antioxidant potential of ethanolic extract and ethyl acetate fraction from basil leaf. The basil leaf was extracted by maceration using ethanol 70 %. The crude extract was fractionated with ethyl acetate. The ethanolic extract and ethyl acetate fraction were screened of phytochemical content including identification of flavonoids, alkaloids and polyphenolics. The antioxidant activity of the ethanolic extract and ethyl acetate fraction were tested qualitatively with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and phosphomolybdate. Its antioxidant activity was determined quantitatively using DPPH radical scavenging method. Phytochemical screening test showed that ethanolic extract and ethyl acetate fraction from basil leaf contain flavonoids, polyphenolics, and alkaloids. The qualitative analysis of antioxidant activity of ethanolic extract and ethyl acetate fraction from basil leaf showed an antioxidant activity. The IC50 value of ethanolic extract, ethyl acetate fraction and quercetin were 1,374.00±6.20 389.00±1.00 2.10±0.01μg/mL, respectively. The research showed that antioxidant activity of the ethyl acetate fraction more potential than the ethanol extract of the basil leaf, but less than quercetin.

  14. 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.

    Science.gov (United States)

    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.

  15. 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

    Science.gov (United States)

    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

  16. Consumption of strawberries on a daily basis increases the non-urate 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity of fasting plasma in healthy subjects

    Science.gov (United States)

    Prymont-Przyminska, Anna; Zwolinska, Anna; Sarniak, Agata; Wlodarczyk, Anna; Krol, Maciej; Nowak, Michal; de Graft-Johnson, Jeffrey; Padula, Gianluca; Bialasiewicz, Piotr; Markowski, Jaroslaw; Rutkowski, Krzysztof P.; Nowak, Dariusz

    2014-01-01

    Strawberries contain anthocyanins and ellagitanins which have antioxidant properties. We determined whether the consumption of strawberries increase the plasma antioxidant activity measured as the ability to decompose 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) in healthy subjects. The study involved 10 volunteers (age 41 ± 6 years, body weight 74.4 ± 12.7 kg) that consumed 500 g of strawberries daily for 9 days and 7 matched controls. Fasting plasma and spot morning urine samples were collected at baseline, during fruit consumption and after a 6 day wash-out period. DPPH decomposition was measured in both deproteinized native plasma specimens and pretreated with uricase (non-urate plasma). Twelve phenolics were determined with HPLC. Strawberries had no effect on the antioxidant activity of native plasma and circulating phenolics. Non-urate plasma DPPH decomposition increased from 5.7 ± 0.6% to 6.6 ± 0.6%, 6.5 ± 1.0% and 6.3 ± 1.4% after 3, 6 and 9 days of supplementation, respectively. The wash-out period reversed this activity back to 5.7 ± 0.8% (p<0.01). Control subjects did not reveal any changes of plasma antioxidant activity. Significant increase in urinary urolithin A and 4-hydroxyhippuric (by 8.7- and 5.9-times after 6 days of supplementation with fruits) was noted. Strawberry consumption can increase the non-urate plasma antioxidant activity which, in turn, may decrease the risk of systemic oxidants overactivity. PMID:25120279

  17. Determination of DPPH free radical scavenging activity

    African Journals Online (AJOL)

    Pavle

    2012-06-05

    Jun 5, 2012 ... possibility to use essential oils and/or their components in medical and plant pathology as well as ... Spectrophotometric measurements were performed using a UV-VIS spectrophotometer MA9523-SPEKOL ... concentration of 0.5% (v/v) for analysis of oil) was added to the other wells. A volume of 50 µl from ...

  18. Spatial mode cleaning in radically asymmetric strongly focused laser beams

    Science.gov (United States)

    Heins, Alan M.; Guo, Chunlei

    2013-12-01

    We demonstrate that a femtosecond laser pulse strongly focused in air can produce a highly symmetric damage pattern on glass. This damage pattern contains a series of near-perfect radial rings, with diameters much larger than the predicted focal spot diameter. These rings disappear when the experiment is conducted in vacuum, indicating atmospheric involvement. Surprisingly, the shape and size of the rings seem to be nearly independent of the shape of the generating laser beam, showing dramatic spatial mode cleaning. A "half moon" initial laser mode created by obscuring one side of the round beam produces rings of similar quality to those obtained with the unclipped beam. While spatial mode cleaning has previously been reported in filaments, this is the most dramatic demonstration of the effect that we are aware of. We argue that the effect is due primarily to ionization, in contrast to studies in longer filaments that attribute it to self-focusing.

  19. Genesis and development of DPPH method of antioxidant assay

    OpenAIRE

    Kedare, Sagar B.; Singh, R. P.

    2011-01-01

    α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method offers the first approach for evaluating the antioxidant potential of a compound, an extract or other biological sources. This is the simplest method, wherein the prospective compound or extract is mixed with DPPH solution and absorbance is recorded after a defined period. However, with the advancement and sophistication in instrumental techniques, the method has undergone various modifications to suit the requirements, even...

  20. Genesis and development of DPPH method of antioxidant assay.

    Science.gov (United States)

    Kedare, Sagar B; Singh, R P

    2011-08-01

    α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method offers the first approach for evaluating the antioxidant potential of a compound, an extract or other biological sources. This is the simplest method, wherein the prospective compound or extract is mixed with DPPH solution and absorbance is recorded after a defined period. However, with the advancement and sophistication in instrumental techniques, the method has undergone various modifications to suit the requirements, even though the basic approach remains same in all of them. This article presents a critical review on various developments to the DPPH method.

  1. DPPH

    African Journals Online (AJOL)

    채소

    samples of root and short were added to 10 ml of lysis solution. (sulfuric acid: hypochlorous acid: distilled ... Distilled water was added to a 300 ml polyethylene beaker containing 25 ml of the lysis solution until the volume ..... vities in the plasma or chloroplasts, while K+ is charac- terized by the fact that it does not interfere ...

  2. A novel high throughput method based on the DPPH dry reagent array for determination of antioxidant activity.

    Science.gov (United States)

    Musa, Khalid Hamid; Abdullah, Aminah; Kuswandi, Bambang; Hidayat, M Amrun

    2013-12-15

    A stable chromogenic radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) is commonly used for the determination of antioxidant activity. In this paper, DPPH was dried into 96 well microplate to produce DPPH dry reagent array plate, based on which the highly sensitive and high throughput determination of antioxidant activities was achieved. The spectrophotometric characterization of the microplate containing dried or fresh DPPH free radicals was reported. The response of the DPPH dry reagent array towards different standard antioxidants was studied. The reaction for DPPH in fresh or dry reagent array with Trolox was reported and compared. The DPPH dry reagent array was used to study the antioxidant activity of banana, green tea, pink guava, and honeydew and the results were compared to the samples reacted with freshly prepared DPPH. The proposed method is comparable to the classical DPPH method, more convenient, simple to operate with minimal solvent required and excellent sensitivity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Analysis of the radical hydrogen transfer pathway for cleaving strong bonds in coal

    Energy Technology Data Exchange (ETDEWEB)

    Autrey, S.T.; Camaioni, D.M.; Ferris, K.F.; Franz, J.A.

    1993-09-01

    Hydrogen transfer processes involving radical intermediates are of key importance in the liquefaction of coal. While the primary function of donor solvents is to transfer H{lg_bullet} to coal-derived radicals that form when weak bonds are cleaved thermolytically, growing evidence suggests that the donor solvent can play a role in promoting cleavage of strong {alpha}-bonds. McMillen and Malhotra have explained the results in terms of a single-step mechanism referred to as radical H-transfer (RHT). Mechanistic kinetic models have been used to suggest the importance of RHT pathways in anthracene- and pyrene-based solvent systems. However, we question the reliability of these approaches because little experimental data exists to support the 16.5 kcal/mol intrinsic barriers they assume for RHT reactions. Unambiguous evidence for RHT is very difficult to obtain experimentally because at the temperatures required to activate the RHT reaction, a suite of multistep reactions can occur, which yield the same products, i.e. H-elimination from hydroaryl radicals followed by ipso addition. For this reason, we have sought to gain insight to barrier heights for RHT from theory. This paper reports our use of Marcus theory in combination with ab initio and semiempirical molecular orbital methods to show how the intrinsic barriers for RHT reactions depend on structural and thermodynamic properties of the reacting partners. In addition, reactions thought to be mediated by RHT are reexamined using mechanistic kinetic modeling (MKM) to determine the extent to which these reactions can be explained by conventional pathways.

  4. Comparative study of the anti-oxidant activity of the total polyphenols extracted from Hibiscus Sabdariffa L., Glycine max L. Merr., yellow tea and red wine through reaction with DPPH free radicals

    Directory of Open Access Journals (Sweden)

    T. Andzi Barhé

    2016-01-01

    Full Text Available The present study is part of the evaluation of extracts of Glycine max L. Merr and Hibiscus L. Sabdariffa as antioxidants. A comparative study was performed with extracts of yellow tea and commercial red wine, two foods known for their antioxidant activity. The method applied is free radical scavenging using the 1,1-diphenyl-2-picrylhydrazyl (DPPH°. The antioxidant properties were identified and measured by the determining the anti-radical activity reducing index, expressed in percentage % RSA (Radical Scavenger Activity, and by the determination of the colouring intensity (IC50. All results are compared to those of ascorbic acid as reference antioxidant. The results indicate the following order for the antioxidant power of the extracts tested. % RSA (tea > % RSA (Glycine max % > RSA (red wine % > RSA (Sabdariffa Hibiscus, and colouring intensities (IC50 ranging from 4.62 μM (ascorbic acid to 1.10 μM (Hibiscus sabdariffa correlated with their chemical structure and the content of phenolic compounds.

  5. Radical scavenging activity of crude polysaccharides from Camellia sinensis

    Directory of Open Access Journals (Sweden)

    Yang Fan

    2011-01-01

    Full Text Available A preparation of crude polysaccharides (TPS was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.

  6. Probing the interaction of human serum albumin with DPPH in the absence and presence of the eight antioxidants.

    Science.gov (United States)

    Li, Xiangrong; Chen, Dejun; Wang, Gongke; Lu, Yan

    2015-02-25

    Albumin represents a very abundant and important circulating antioxidant in plasma. DPPH radical is also called 2,2-diphenyl-1-picrylhydrazyl. It has been widely used for measuring the efficiency of antioxidants. In this paper, the ability of human serum albumin (HSA) to scavenge DPPH radical was investigated using UV-vis absorption spectra. The interaction between HSA and DPPH was investigated in the absence and presence of eight popular antioxidants using fluorescence spectroscopy. These results indicate the antioxidant activity of HSA against DPPH radical is similar to glutathione and the value of IC50 is 5.200×10(-5) mol L(-1). In addition, the fluorescence experiments indicate the quenching mechanism of HSA, by DPPH, is a static process. The quenching process of DPPH with HSA is easily affected by the eight antioxidants, however, they cannot change the quenching mechanism of DPPH with HSA. The binding of DPPH to HSA primarily takes place in subdomain IIA and exists two classes of binding sites with two different interaction behaviors. The decreased binding constants and the number of binding sites of DPPH with HSA by the introduction of the eight antioxidants may result from the competition of the eight antioxidants and DPPH binding to HSA. The binding of DPPH to HSA may induce the micro-environment of the lone Trp-214 from polar to slightly nonpolar. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Strong deviations from the NO-NO2-O3 photostationary state in the Pearl River Delta: Indications of active peroxy radical and chlorine radical chemistry

    Science.gov (United States)

    Ma, Yufang; Lu, Keding; Chou, Charles C.-K.; Li, Xiaoqian; Zhang, Yuanhang

    2017-08-01

    Simultaneous measurements of meteorological data, trace gases, and volatile organic compounds were made in two regional sites, viz. Backgarden and Kaiping, in the Pearl River Delta (PRD) during summer and autumn, respectively. The strong deviations from the NO-NO2-O3 Photostationary State, quantified by the leighton ratios, are carefully deduced through a comprehensive data set consist of the high-quality measurements of NO, NO2, O3 and JNO2 as well as the peroxy radical measurements. This is the first report of the Leighton ratio in China, with relatively high recorded values of 2.3 ± 0.4 (Backgarden) and 3.1 ± 1.4 (Kaiping), suggesting a strongly oxidising atmosphere in the PRD, typical of the ozone pollution season. A sensitivity analysis using a zero-dimensional chemical box model based on the regional atmospheric chemistry mechanism, version 2 (RACM2) constrained by the experimental measurements, indicated that peroxy radicals account for 70 (Backgarden) and 66% (Kaiping) of the observed positive deviations from the NOx photostationary state (characterized by a Leighton ratio of 1) on average. We consider that the remaining deviations result from neglecting the effects of chlorine chemistry, so we introduced a Cl chemistry module into RACM2, and the modelled results for Cl were as follows: 4.7 × 10-4 pptv in Backgarden and 1.3 × 10-3 pptv in Kaiping; these results are lower than the Cl concentration derived from the NOx photostationary state. More work is required to confirm the role of additional peroxy radical sources at both high and low NOx regimes, as well as that of the halogen radicals, in perturbing the NO-NOx-O3 cycle, which would significantly enhance trace gas removal and photochemical ozone production.

  8. Measurement of angular correlations of jets at {radical}(s)=1.96 TeV and determination of the strong coupling at high momentum transfers

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Abbott, B. [University of Oklahoma, Norman, OK 73019 (United States); Acharya, B.S. [Tata Institute of Fundamental Research, Mumbai (India); Adams, M. [University of Illinois at Chicago, Chicago, IL 60607 (United States); Adams, T. [Florida State University, Tallahassee, FL 32306 (United States); Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Alkhazov, G. [Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Alton, A. [University of Michigan, Ann Arbor, MI 48109 (United States); Alverson, G. [Northeastern University, Boston, MA 02115 (United States); Askew, A. [Florida State University, Tallahassee, FL 32306 (United States); Atkins, S. [Louisiana Tech University, Ruston, LA 71272 (United States); Augsten, K. [Czech Technical University in Prague, Prague (Czech Republic); Avila, C. [Universidad de los Andes, Bogota (Colombia); Badaud, F. [LPC, Universite Blaise Pascal, CNRS/IN2P3, Clermont (France); Bagby, L.; Baldin, B. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Bandurin, D.V. [Florida State University, Tallahassee, FL 32306 (United States); Banerjee, S. [Tata Institute of Fundamental Research, Mumbai (India); Barberis, E. [Northeastern University, Boston, MA 02115 (United States); Baringer, P. [University of Kansas, Lawrence, KS 66045 (United States); and others

    2012-11-15

    We present a measurement of the average value of a new observable at hadron colliders that is sensitive to QCD dynamics and to the strong coupling constant, while being only weakly sensitive to parton distribution functions. The observable measures the angular correlations of jets and is defined as the number of neighboring jets above a given transverse momentum threshold which accompany a given jet within a given distance {Delta}R in the plane of rapidity and azimuthal angle. The ensemble average over all jets in an inclusive jet sample is measured and the results are presented as a function of transverse momentum of the inclusive jets, in different regions of {Delta}R and for different transverse momentum requirements for the neighboring jets. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron Collider in pp{sup Macron} collisions at {radical}(s)=1.96 TeV. The results are well described by a perturbative QCD calculation in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects. From these results, we extract the strong coupling and test the QCD predictions for its running over a range of momentum transfers of 50-400 GeV.

  9. Antiradical properties of commercial cognacs assessed by the DPPH(.) test.

    Science.gov (United States)

    Da Porto, C; Calligaris, S; Celotti, E; Nicoli, M C

    2000-09-01

    Antiradical activities of some commercial cognacs were evaluated by the DPPH(*) test. Different mathematical models for the evaluation of the antiradical efficiency of the cognac samples were proposed and discussed. Nonflavonoid phenols were found to be the main substances responsible of the radical scavenging activity of cognacs. In particular the strongest correlations between antiradical activity measurements and cognac chemical characteristics was found for ellagitannins, high molecular weight polyphenols, which are extracted from the wood and solubilized in the spirit mainly during first year aging.

  10. on anioxidant enzymes and DPPH-Radical scavenging activity of ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 2 (2009) >. Log in or Register to get access to full text downloads.

  11. enhancing production through optimisation of dpph and radical

    African Journals Online (AJOL)

    ACSS

    using the compressed hot water and solvent extraction techniques. Polyphenols were extracted from milled (<0.5 mm) and whole grape seed, using compressed hot water (high temperature and high pressure) and solvents. (Acetone, Methanol and .... hot air oven for 1 and 2 hours for each sample. After extraction, the ...

  12. Evaluation of Free Radical Scavenging Activity in Ethanolic Extract from Promising Accessions of Curcuma aeruginosa RoxB.

    Directory of Open Access Journals (Sweden)

    Waras Nurcholis

    2017-11-01

    Full Text Available This study evaluated the free radical scavenging activity in ethanolic extracts from 20 accessions of Curcuma aeruginosa. The radical scavenging activity of the extract accessions was investigated with 2,2-diphenyl-1-picrylhydrazyl (DPPH radical. IC50 values for DPPH radical scavenging activity ranged from 89.81 to 505.65 µg mL-1. Based on IC50 values, twenty accessions of C. aeruginosa can be divided into three groups: strong (two accessions; moderate (seventeen accessions; and low (one accession of DPPH scavenger. Sukoharjo (SH and Muara Bungo (MB showed promising accessions for antioxidant potential, thus these accessions important to selection for future breeding program in pharmaceutical products.

  13. Kinetic study of DPPH scavenging in the presence of mixture of Zinc and Vitamin C as an antioxidant

    Directory of Open Access Journals (Sweden)

    M. Momen Heravi

    2012-08-01

    Full Text Available Reactions of free radicals and reactive oxygen species (ROS with biological molecules in vivo play an important physiological role in many diseases. 2,2-diphenyl-1-picrylhydrazyl (DPPH is a stable free radical and often used as a routine reagent to evaluate the antioxidant capacity of an antioxidant. This study was undertaken to investigate the free radical-scavenging and antioxidant activities of Zinc, Vitamin C and mixture of them. UV-Vis spectrophotometry method was used to evaluate the ability of Zinc, Vitamin C and mixture of them to scavenge DPPH radical. The kinetic parameters such as rate constant and activation energy in experimental conditions were calculated. The rate constants of the H atom abstraction by DPPH (, in the presence of Zinc, Vitamin C and mixture of them were obtained (0.4209, 2.092 and 1.82 min-1 respectively, under pseudo-first-order conditions at 25 oC.

  14. Free radical scavenging activity of extracts prepared from fresh leaves of selected Chinese medicinal plants.

    Science.gov (United States)

    Hu, Fenglin; Lu, Ruili; Huang, Bao; Liang, Ming

    2004-01-01

    The free radical scavenging activity of the 80% methanolic extracts from fresh leaves of 300 Chinese medical woody plants was assessed with the aid of the stable DPPH radical. Among the plants screened, 56 species had strong free radical scavenging capacities, with IC50 values lower than 0.5 mg leaves per milliliter. Analysis of the medical uses of these plants showed that most of them are employed for their effects on hemostasis, as anti-inflammatory, antimicrobial or for treatment of dysentery. These uses may be directly linked to the content in tannins and flavonoids and consequently to their free radical scavenging activities.

  15. AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL KULIT BUAH RAMBUTAN (Nephelium lappaceum L. ) TERHADAP PENANGKAPAN RADIKAL BEBAS DPPH

    OpenAIRE

    Anshory, Hady; Suparmi, Suparmi; Tamimy, Arif Setiadi

    2012-01-01

    ABSTRACTRambutan fruits are consumed by people for additional food and medical use. Pericarp oframbutan has been known to have some active compounds such as flavonoid. Many flavonoidsfrom plants are known to have anti radical activity effect or antioxidant. It is very interest todetermine of antioxidant activity from ethanol extract of rambutan pericarp (Nephelium lappaceumL.). Antioxidant activity was carried out spectrophotometry by using DPPH (2,2-diphenyl-1-picrylhydrazyl) as a reagent. T...

  16. Effect of carboxymethylation on antioxidant properties and radical degradation of mannans and glucans.

    Science.gov (United States)

    Machová, Eva; Čížová, Alžbeta; Bystrický, Peter

    2014-11-04

    Carboxymethyl derivatives (CM-derivatives) of α,β-mannans from yeasts, Saccharomyces cerevisiae β-glucan and dextran (α-glucan) were found to possess strong antioxidant activities against reactive hydroxyl radicals (OH*) compared to underivatized polysaccharides. When CM-derivatives having similar DS (0.41-0.45) were compared, the antioxidant activity decreased in order CM-mannan>CM-β-glucan>CM-dextran. Moreover, the antioxidant activities against OH* increased with increasing degree of substitution (DS) of polysaccharides. The CM-mannan and CM-dextran with the highest DS (0.73 and 1.1, respectively) were the strongest antioxidants and their degradation by OH* decreased with increased carboxymethylation. The scavenging abilities of CM-polysaccharides against stable DPPH radical (DPPH) were lower than those of original underivatized ones. Also this scavenging property against DPPH was lower compared to antioxidant effect against OH*. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. In vitro free radical scavenging activity of Ixora coccinea L

    Directory of Open Access Journals (Sweden)

    Moni Rani Saha

    2008-06-01

    Full Text Available Antioxidant activity of the methanol extract of Ixora coccinea L. was determined by DPPH free radical scavenging assay, reducing power and total antioxidant capacity using phosphomolybdenum method. Preliminary phytochemical screening revealed that the extract of the flower of I. coccinea possesses flavonoids, steroids and tannin materials. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner and remarkable activities to scavenge reactive oxygen species (ROS may be attributed to the high amount of hydrophilic phenolics. In DPPH radical scavenging assay the IC50 value of the extract was found to be 100.53 μg/mL while ascorbic acid had the IC50 value 58.92 μg/mL. Moreover, I. coccinea extract showed strong reducing power and total antioxidant capacity.

  18. In vitro antibacterial and free radical scavenging activity of green hull of Juglans regia

    Directory of Open Access Journals (Sweden)

    Pardeep Sharma

    2013-08-01

    Full Text Available Antioxidant supplements from plants are vital to count the oxidative damage in cells. We assessed the antioxidants and antibacterial activity of green hull of Juglans regia in this study. According to our results the maximum antibacterial activity was observed in ethanolic extract when compared to other extract. So, the ethanolic extract was studied for antioxidant activity which exhibited high antiradical activity against DPPH, hydroxyl, and nitric oxide radicals. In conclusion, green hull of J. regia showed strong reducing power activity and total antioxidant capacity. The results justify the therapeutic application of plant in the indigenous system of medicine. Keywords: Juglans regia, Ethanolic extract, Antioxidants, DPPH, Antibacterial activity

  19. Anti-free radical activities of kaempferol isolated from Acacia nilotica (L.) Willd. Ex. Del.

    Science.gov (United States)

    Singh, Rajbir; Singh, Bikram; Singh, Sukhpreet; Kumar, Neeraj; Kumar, Subodh; Arora, Saroj

    2008-12-01

    In the present study the polyphenolic compound has been isolated from methanol extract of Acacia nilotica Willd. Ex. Del. which has been identified as kaempferol (AN-5) by NMR and mass spectroscopy. The antioxidant potential of the AN-5 was demonstrated in several in vitro assays: measuring the proton radical scavenging activity (DPPH scavenging assay), hydroxyl radical scavenging activity (deoxyribose degradation assay), metal chelating activity, reducing power and inhibition of lipid peroxidation. It was found that the effect of the compound AN-5 was strongly dose dependent up to the concentrations 1-50 microg/ml in DPPH assay and 1-100 microg/ml in deoxyribose degradation assay but did not show further change above the highest concentrations.

  20. Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

    Directory of Open Access Journals (Sweden)

    George E. Williams

    2016-07-01

    Full Text Available Proterozoic (pre-Ediacaran glaciations occurred under strongly seasonal climates near sea level in low palaeolatitudes. Metre-scale primary sand wedges in Cryogenian periglacial deposits are identical to those actively forming, through the infilling of seasonal (winter thermal contraction-cracks in permafrost by windblown sand, in present-day polar regions with a mean monthly air temperature range of 40 °C and mean annual air temperatures of −20 °C or lower. Varve-like rhythmites with dropstones in Proterozoic glacial successions are consistent with an active seasonal freeze–thaw cycle. The seasonal (annual oscillation of sea level recorded by tidal rhythmites in Cryogenian glacial successions indicates a significant seasonal cycle and extensive open seas. Palaeomagnetic data determined directly for Proterozoic glacial deposits and closely associated rocks indicate low palaeolatitudes: Cryogenian deposits in South Australia accumulated at ≤10°, most other Cryogenian deposits at 54° during Proterozoic low-latitude glaciations, whereby the equator would be cooler than the poles, on average, and global seasonality would be greatly amplified.

  1. Main flavonoids, DPPH activity, and metal content allow determination of the geographical origin of propolis from the Province of San Juan (Argentina).

    Science.gov (United States)

    Lima, Beatriz; Tapia, Alejandro; Luna, Lorena; Fabani, María P; Schmeda-Hirschmann, Guillermo; Podio, Natalia S; Wunderlin, Daniel A; Feresin, Gabriela E

    2009-04-08

    The chemical characterization as well as the assessment of geographical origin of propolis from several areas of the Provincia de San Juan (Argentina) is reported. Chemical characterization of propolis was performed by measuring total phenolic (TP), total flavonoids (FL), free radical scavenging capacity (DPPH bleaching), and metal content in samples of six different districts. Methanolic propolis extracts (MEP) showed TP ranging from 25.7 to 39.3 g of gallic acid equivalents per 100 g of MEP, whereas flavonoids ranged from 6.6 to 13.3 g of quercetin equivalents per 100 g of MEP. Six main flavonoids were isolated and identified from the propolis samples, comprising the flavanones 7-hydroxy-8-methoxyflavanone (1), pinocembrin (2), and pinobanksin (3), the flavones chrysin (4) and tectochrysin (5), and the flavonol galangin (6). Compounds 1-6 were quantified by HPLC-PDA. Free radical scavenging activity, measured as percent DPPH bleaching, ranged from 46.6 to 89.5 at 10 mug/mL. Moreover, propolis samples presented high contents of Ca, K, Fe, Na, and Mg, but low amounts of Mn and Zn. Linear discriminant analysis affords eight descriptors, galangin, pinocembrin, pinobanksin, chrysin, tectochrysin, DPPH, K, and Na, allowing a clear distinction with 100% accuracy among different origins within the Provincia de San Juan. A direct relationship of DPPH free radical scavenging activity with TP or with compounds 1-6 was not found, showing the need of further evaluation on the origin of free radical activity in propolis samples.

  2. Free radical scavenging activity of Lafoensia pacari.

    Science.gov (United States)

    Solon, S; Lopes, L; Teixeira de Sousa, P; Schmeda-Hirschmann, G

    2000-09-01

    The methanolic extract of the stem bark of Lafoensia pacari (Lythraceae) showed free radical scavenging activity in the diphenyl picryl hydrazyl radical (DPPH) decoloration assay and inhibited the enzyme xanthine oxidase 'in vitro'. Bioassay-guided isolation led to ellagic acid (EA) as the main active compound of Brazilian and Paraguayan collections of the plant.

  3. A novel VU-MRCC formalism for the simultaneous treatment of strong relaxation and correlation effects with applications to electron affinity of neutral radicals

    International Nuclear Information System (INIS)

    Jana, Debasis; Datta, Dipayan; Mukherjee, Debashis

    2006-01-01

    We present and implement in this paper a novel spin-free valence-universal multi-reference coupled cluster (VU-MRCC) formalism for energy differences which can capture orbital relaxation and correlation relaxation to all orders. Unlike in the traditional normal ordered cluster Ansatz for computing energy differences, this cluster expansion formalism allows contractions between various valence excitation operators with valence spectator lines. These contractions simulate the orbital relaxation and correlation relaxation effects for the ionized/excited states via Thouless-like exponential type of operators. Generally such operators are non-commuting. To ensure that each distinct excitation generated by contracted composites formed by these operators appear only once in the wave-operators, the factors accompanying these composites have to be judiciously chosen. Hence, the combinatoric factors accompanying such contracted composites are not taken to be 1/n! for nth-power, but rather the inverse of the automorphic factor (the number of ways the n operators can be connected in various permutations generating the same composite). It is shown that this Ansatz leads to a set of VU-MRCC equations for the valence cluster amplitudes, in which all the cluster operators are attached to the hamiltonian by at least one non-spectator line (a strongly connected series). The series is thus terminating at the quartic power. Illustrative applications are presented by computing electron affinity of neutral doublet radicals (viz., NH 2 , OH, F, BO and CN), where the orbital relaxation effect attendant on the anion formation is considerable. Several basis-sets capable of describing the anions have been studied. It has been found that aug-cc-pVTZ basis gives the best overall results, while aug-cc-pVQZ overestimates the electron affinity, presumably because of an imbalance in describing the neutral radicals. The method performs consistently much better then the one with the traditional

  4. Evaluation of Anti-Oxidant Activity of Lavandula angustifolia using DPPH Method

    Directory of Open Access Journals (Sweden)

    Masoud Soheili

    2017-03-01

    Full Text Available Abstract Background: Stress oxidative factors are known to causes diseases resulting from metabolic disorders. Therefore, preventing, or at least decreasing the amount of these factors may have a positive impact on prevention or improvement of the metabolic problems. Recently, the herbal medicines are more considered due to more effectiveness. We designed the present study to evaluate anti-oxidant effect of aqueous extract of lavender (Lavandula angustifolia. Materials and Methods: For extract preparation, the dry aerial part of lavender mixed with boiling water for 4 hours and then the container was filtered and condensed in a bain marie. Finally, the extract was powdered by freeze dryer. The anti-oxidant activities of the herbal medicine samples in 5, 10, 20 and 40 ppm concentrations were determined via DPPH method. This method is based on free radical scavenging of 2, 2- dipheny L-1-picrylhydrazyl(DPPH reflected in the color and absorbance changes in spectrophotometery method in 520 nm. Finally the IC50 was calculated and compared with that of for vitamin C as a standard. Results: All doses of the aqueous extract of the lavender showed dose- dependent potent anti-oxidant activity, So that, their differences were significant compared to control sample. The IC50 of the herbal medicine was 24.66 ppm that was less than the vitamin C of 2.3 ppm. Conclusion: As a potent anti-oxidant, the lavender aqueous extract can be effective in treatment of metabolic diseases.

  5. Free Radical Scavenging Activity of Drops and Spray Containing Propolis—An EPR Examination

    OpenAIRE

    Pawel Olczyk; Katarzyna Komosinska-Vassev; Pawel Ramos; Lukasz Mencner; Krystyna Olczyk; Barbara Pilawa

    2017-01-01

    The influence of heating at a temperature of 50 °C and UV-irradiation of propolis drops and spray on their free radical scavenging activity was determined. The kinetics of interactions of the propolis samples with DPPH free radicals was analyzed. Interactions of propolis drops and propolis spray with free radicals were examined by electron paramagnetic resonance spectroscopy. A spectrometer generating microwaves of 9.3 GHz frequency was used. The EPR spectra of the model DPPH free radicals we...

  6. Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

    OpenAIRE

    Suvankar Das; Cristiane J. da Silva; Marina de M. Silva; Maria Dayanne de A. Dantas; Ângelo de Fátima; Ana Lúcia T. Góis Ruiz; Cleiton M. da Silva; João Ernesto de Carvalho; Josué C.C. Santos; Isis M. Figueiredo; Edeildo F. da Silva-Júnior; Thiago M. de Aquino; João X. de Araújo-Júnior; Goutam Brahmachari; Luzia Valentina Modolo

    2018-01-01

    Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the anion radical superoxide (·O2−). The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine...

  7. Target-guided isolation and purification of antioxidants from Selaginella sinensis by offline coupling of DPPH-HPLC and HSCCC experiments.

    Science.gov (United States)

    Zhang, Yuping; Shi, Shuyun; Wang, Yuanxi; Huang, Kelong

    2011-01-15

    Selaginella sinensis (Selaginellaceae) is used extensively in traditional Chinese medicine (TCM) for the treatment of many kinds of chronic diseases. In this study, fractionation of the methanol extract of S. sinensis by different polarity solvents indicated the ethyl acetate fraction exhibited an potent 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity with the IC(50) value of 44.9 μM. In order to evaluate the scientific basis, antioxidant peaks were firstly screened using DPPH spiking test through high performance liquid chromatography (DPPH-HPLC). Under the target-guidance of DPPH-HPLC experiment, two flavonoids and six biflavonoids, quercetin (1), apigenin (2), amentoflavone (3), robustaflavone (4), 2,3-dihydroamentaflavone (5), hinokiflavone (6), 4'-O-methyl-robustaflavone (7) and ginkgetin (8) were separated by high-speed counter-current chromatography (HSCCC) method using n-hexane-ethyl acetate-methanol-water (8:8:9:7) as the solvent system with purities 98.2%, 97.6%, 99.4%, 92.3%, 98.5%, 98.9% and 99.6%, respectively. The structures were identified by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) analysis. Antioxidant activity of eight isolated compounds was assessed by the radical scavenging effect on DPPH radical, compound 1 showed strongest antioxidant activities with IC(50) values of 3.2 μM, while compounds 2-8 showed weak antioxidant activities. This is the first report on simultaneous separation of eight antioxidant compounds from S. sinensis by HSCCC, moreover, apigenin and 4'-O-methyl-robustaflavone were first identified from this plant. Results of the present study indicated that the combinative method using DPPH-HPLC and HSCCC could be widely applied for rapid screening and isolating of antioxidants from complex TCM extract. Copyright © 2010. Published by Elsevier B.V.

  8. Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines

    Directory of Open Access Journals (Sweden)

    Frantisek Sersen

    2017-05-01

    Full Text Available Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene-N′-[2,6-dinitro-4-(trifluoromethyl]phenylhydrazines. The chemical structures of these compounds were confirmed by 1H-NMR, 13C-NMR, 19F-NMR, IR spectroscopy, LC-MS, and elemental analysis. The prepared compounds were tested for their activity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH, galvinoxyl radical (GOR, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS radicals. The free radical scavenging activity expressed as SC50 values of these compounds varied in a wide range, from a strong to no radical scavenging effect. The most effective radical scavengers were hydroxybenzylidene hydrazines containing three hydroxyl groups in the benzylidene part of their molecules. The prepared compounds were also tested for their activity to inhibit photosynthetic electron transport in spinach chloroplasts. IC50 values of these compounds varied in wide range, from an intermediate to no inhibitory effect.

  9. Free Radical Scavenging Properties of Annona squamosa

    Science.gov (United States)

    Vikas, Biba; S, Akhil B; P, Remani; Sujathan, K

    2017-01-01

    Annona squamosa has extensively been used in the traditional and folkloric medicine and found to possess many biological activities. Different solvents, petroleum ether, chloroform, ethyl acetate and methanol extracts of Annona squamosa seeds (ASPE, ASCH, ASEA, ASME) have been used to prepare plant extracts. The present investigations dealt with the free radical scavenging activity of four extracts using various techniques such as total reducing power estimation, total phenolic count, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect, evaluation of ABTS cation decolorisation capacity, FRAP assay, hdroxyl radical scavenging assay, super oxide assay and Nitric oxide radical scavenging assay of the extracts. The results showed that the four extracts of Annona squamosa showed significant reducing power in four extracts. The total phenolic contents in petroleum ether, chloroform, ethyl acetate, methanol extracts and positive control were 0.64±0.17, 0.54±0.27, 0.49±0.24, 0.57±0.22 and 0.66±0.33. The antioxidant capacity by ABTS assay of ASPE, ASCH, ASEA, ASME and positive control, trolox showed 77.75±0.5,73.25±1.7,78.5± 1.2, 80 ± 0.8 μg/ml and 94.2 ± 0.9 respectively. The (50 % scavenging activity) SA50 of ASPE and ASCH, ASEA and ASME was found to be 34.4 µg/ml, 43.8 µg/ml 34.7 µg/m and 28.8 µg/ml respectively by DPPH assay. The percentage of hydroxyl radical scavenging increased with the increasing concentration of the extracts. ASPE, ASCH, ASEA and ASME showed superoxide radical scavenging activity, as indicated by their values 66 ± 0.5, 68 ± 1, 63 ± 1 and 70 ± 0.5 μg/ml respectively compared to gallic acid which was 97 ± 0.5 μg/ml. The values for scavenging of nitric oxide for ASPE, ASCH, ASEA and ASME were 91.0 ± 1.0, 66.75 ± 0.5, 71.75 ± 1.1 and 75.75 ± 1.15 μg/ml while value for standard ascorbic acid was 91.0 ± 1.0 μg/ml. The results revealed strong antioxidants in four extracts may lead to the development of potent

  10. Free Radical Scavenging Properties of Annona squamosa

    Science.gov (United States)

    Vikas, Biba; Akhil B, S; P, Remani; Sujathan, K

    2017-10-26

    Annona squamosa has extensively been used in the traditional and folkloric medicine and found to possess many biological activities. Different solvents, petroleum ether, chloroform, ethyl acetate and methanol extracts of Annona squamosa seeds (ASPE, ASCH, ASEA, ASME) have been used to prepare plant extracts. The present investigations dealt with the free radical scavenging activity of four extracts using various techniques such as total reducing power estimation, total phenolic count, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect, evaluation of ABTS cation decolorisation capacity, FRAP assay, hdroxyl radical scavenging assay, super oxide assay and Nitric oxide radical scavenging assay of the extracts. The results showed that the four extracts of Annona squamosa showed significant reducing power in four extracts. The total phenolic contents in petroleum ether, chloroform, ethyl acetate, methanol extracts and positive control were 0.64±0.17, 0.54±0.27, 0.49±0.24, 0.57±0.22 and 0.66±0.33. The antioxidant capacity by ABTS assay of ASPE, ASCH, ASEA, ASME and positive control, trolox showed 77.75±0.5,73.25±1.7,78.5± 1.2 , 80 ± 0.8 μg/ml and 94.2 ± 0.9 respectively. The (50 % scavenging activity) SA50 of ASPE and ASCH, ASEA and ASME was found to be 34.4 μg/ml, 43.8 μg/ml 34.7 μg/m and 28.8 μg/ml respectively by DPPH assay. The percentage of hydroxyl radical scavenging increased with the increasing concentration of the extracts. ASPE, ASCH, ASEA and ASME showed superoxide radical scavenging activity, as indicated by their values 66 ± 0.5, 68 ± 1 ,63 ± 1 and 70 ± 0.5 μg/ml respectively compared to gallic acid which was 97 ± 0.5 μg/ml. The values for scavenging of nitric oxide for ASPE, ASCH, ASEA and ASME were 91.0 ± 1.0, 66.75 ± 0.5, 71.75 ± 1.1 and 75.75 ± 1.15 μg/ml while value for standard ascorbic acid was 91.0 ± 1.0 μg/ml. The results revealed strong antioxidants in four extracts may lead to the development of potent

  11. Identification of radical scavengers in sweet grass (Hierochloe odorata).

    Science.gov (United States)

    Pukalskas, Audrius; van Beek, Teris A; Venskutonis, Rimantas P; Linssen, Jozef P H; van Veldhuizen, Albertus; de Groot, Aede

    2002-05-08

    Extracts from aerial parts of sweet grass (Hierochloe odorata) were active DPPH free radical scavengers. The active compounds were detected in extract fractions using HPLC with on-line radical scavenging detection. After multistep fractionation of the extract, two new natural products possessing radical scavenging activity were isolated, and their structures were elucidated by NMR and MS. They were identified as 5,8-dihydroxybenzopyranone and 5-hydroxy-8-O-beta-D-glucopyranosyl-benzopyranone. Activities of the compounds isolated were tested by DPPH and ABTS free radical scavenging assays, and compared with the known natural antioxidant rosmarinic acid and Trolox.

  12. Antioxidant activity via DPPH, gram-positive and gram-negative antimicrobial potential in edible mushrooms.

    Science.gov (United States)

    Ahmad, Nisar; Mahmood, Fazal; Khalil, Shahid Akbar; Zamir, Roshan; Fazal, Hina; Abbasi, Bilal Haider

    2014-10-01

    Edible mushrooms (EMs) are nutritionally rich source of proteins and essential amino acids. In the present study, the antioxidant activity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and antimicrobial potential in EMs (Pleurotus ostreatus, Morchella esculenta, P. ostreatus (Black), P. ostreatus (Yellow) and Pleurotus sajor-caju) were investigated. The DPPH radical scavenging activity revealed that the significantly higher activity (66.47%) was observed in Morchella esculenta at a maximum concentration. Similarly, the dose-dependent concentrations (200, 400, 600, 800 and 1000 µg) were also used for other four EMs. Pleurotus ostreatus exhibited 36.13% activity, P. ostreatus (Black (B)) exhibited 30.64%, P. ostreatus (Yellow (Y)) exhibited 40.75% and Pleurotus sajor-caju exhibited 47.39% activity at higher concentrations. Furthermore, the antimicrobial potential were investigated for its toxicity against gram-negative bacterial strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Klebsiella pneumonia, Erwinia carotovora and Agrobacterium tumifaciens), gram-positive bacterial strains (Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus) and a fungal strain (Candida albicans) in comparison with standard antibiotics. Antimicrobial screening revealed that the ethanol extract of P. ostreatus was active against all microorganism tested except E. coli. Maximum zone of inhibition (13 mm) was observed against fungus and A. tumifaciens. P. sajor-caju showed best activities (12.5 mm) against B. subtilis, B. atrophaeus and K. pneumonia. P. ostreatus (Y) showed best activities against P. aeroginosa (21.83 mm), B. atrophaeus (20 mm) and C. albicans (21 mm). P. ostreatus (B) exhibited best activities against C. albicans (16 mm) and slightly lower activities against all other microbes except S. typhi. M. esculenta possess maximum activities in terms of inhibition zone against all microorganisms tested except S. typhi. © The Author(s) 2012.

  13. Scanometry as microplate reader for high throughput method based on DPPH dry reagent for antioxidant assay

    Directory of Open Access Journals (Sweden)

    Mochammad Amrun Hidayat

    2017-05-01

    Full Text Available The stable chromogenic radical 1,1′-diphenyl-2-picrylhydrazyl (DPPH solution was immobilized on the microwell plate as dry reagent to construct a simple antioxidant sensor. Then, a regular flatbed scanner was used as microplate reader to obtain analytical parameters for antioxidant assay using one-shot optical sensors as scanometry technique. Variables affecting the acquisition of the images were optimized and the analytical parameters are obtained from an area of the sensing zone inside microwell using the average luminosity of the sensing zone captured as the mean of red, green, and blue (RGB value using ImageJ® program. By using this RGB value as sensor response, it is possible to determine antioxidant capacity in the range 1–25 ppm as gallic acid equivalent (GAE with the response time of 9 min. The reproducibility of sensor was good (RSD<1% with recovery at 93%–96%. The antioxidant sensor was applied to the plant extracts, such as sappan wood and Turmeric Rhizome. The results are good when compared to the same procedure using a UV/Vis spectrophotometer.

  14. Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic ...

    African Journals Online (AJOL)

    HP

    Results: Extract from Rhizophora mangle L and Krameria erecta displayed 5-fold higher antioxidant capacity than ascorbic acid with DPPH reduction values of 95.71 and 91 %, respectively. Anti-radical kinetic analysis and stoichiometric constant values suggest that the compounds responsible for antioxidant activity are ...

  15. Identification of Radical Scavengers in Sweet Grass (Hierochloe odorata)

    NARCIS (Netherlands)

    Pukalskas, A.; Beek, van T.A.; Venskutonis, R.P.; Linssen, J.P.H.; Veldhuizen, van A.; Groot, de Æ.

    2002-01-01

    Extracts from aerial parts of sweet grass (Hierochloe odorata) were active DPPH free radical scavengers, The active compounds were detected in extract fractions using HPLC with on-line radical scavenging detection. After multistep fractionation of the extract, two new natural products possessing

  16. FREE RADICAL SCAVENGING CAPACITY OF PAPAVER SOMNIFERUM L. AND DETERMINATION OF PHARMACOLOGICALLY ACTIVE ALKALOIDS USING CAPILLARY ELECTROPHORESIS

    Directory of Open Access Journals (Sweden)

    Marián Valko

    2012-02-01

    Full Text Available The free radical generation is related to the oxidation process in biological systems as well as in foods. It was found that oxidation is affected by antioxidants that can act as radical scavengers. Objective of the present work was to study the free radical scavenging capacity of opium poppy (Papaver somniferum L. extract by using the DPPH test and to verify the suitability of the micellar electrokinetic capillary chromatography (MEKC technique for analytical assessment and determination of three major poppy alkaloids (thebaine, morphine and papaverine. Because of its generally high separation efficiency, the MEKC is successfully used for analytical evaluation of biologically active substances usually without special claims for sample preparation. The results of DPPH test have shown that poppy contains components capable of terminating free radicals. We have confirmed that nature of the solvent used for the electrophoretic medium in MEKC has a strong influence on the separation efficiency. In our experiments, the most effective solvent was mixture of water to acetonitrile (ratio 4:6.

  17. Rapid Screening and Preparative Isolation of Antioxidants from Alpinia officinarum Hance Using HSCCC Coupled with DPPH-HPLC Assay and Evaluation of Their Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Lei Fang

    2018-01-01

    Full Text Available An efficient method using high-speed counter-current chromatography (HSCCC coupled with DPPH-HPLC assay has been developed for rapid screening and preparative isolation of antioxidants from ethyl acetate fraction of Alpinia officinarum Hance. Target-guided by DPPH-HPLC assay, two antioxidants, galangin and kaempferide, were targeted and further separated with purities of 99.3% and 98.5% by HSCCC using petroleum ether–ethyl acetate–methanol–water (0.8 : 1 : 1 : 0.8, v/v as the solvent system. The antioxidant activities of galangin and kaempferide were further evaluated by measuring their inhibiting effects on superoxide anion radical, hydroxyl radical, and hydrogen peroxide in different luminol chemiluminescence (CL systems. As a result, galangin and kaempferide both showed potent antioxidant activities. Results of the present study indicated that the combinative method by offline coupling DPPH-HPLC and HSCCC could be widely applied for rapid screening and isolation of antioxidants from complex TCM extract.

  18. Assessment of antioxidant activity of spray dried extracts of Psidium guajava leaves by DPPH and chemiluminescence inhibition in human neutrophils.

    Science.gov (United States)

    Fernandes, M R V; Azzolini, A E C S; Martinez, M L L; Souza, C R F; Lucisano-Valim, Y M; Oliveira, W P

    2014-01-01

    This work evaluated the physicochemical properties and antioxidant activity of spray dried extracts (SDE) from Psidium guajava L. leaves. Different drying carriers, namely, maltodextrin, colloidal silicon dioxide, Arabic gum, and β -cyclodextrin at concentrations of 40 and 80% relative to solids content, were added to drying composition. SDE were characterized through determination of the total phenolic, tannins, and flavonoid content. Antioxidant potential of the SDE was assessed by two assays: cellular test that measures the luminol-enhanced chemiluminescence (LumCL) produced by neutrophils stimulated with phorbol myristate acetate (PMA) and the DPPH radical scavenging (DPPH∗ method). In both assays the antioxidant activity of the SDE occurred in a concentration-dependent manner and showed no toxicity to the cells. Using the CLlum method, the IC50 ranged from 5.42 to 6.50 µg/mL. The IC50 of the SDE ranged from 7.96 to 8.11 µg/mL using the DPPH(•) method. Psidium guajava SDE presented significant antioxidant activity; thus they show high potential as an active phytopharmaceutical ingredient. Our findings in human neutrophils are pharmacologically relevant since they indicate that P. guajava SDE is a potential antioxidant and anti-inflammatory agent in human cells.

  19. Assessment of Antioxidant Activity of Spray Dried Extracts of Psidium guajava Leaves by DPPH and Chemiluminescence Inhibition in Human Neutrophils

    Directory of Open Access Journals (Sweden)

    M. R. V. Fernandes

    2014-01-01

    Full Text Available This work evaluated the physicochemical properties and antioxidant activity of spray dried extracts (SDE from Psidium guajava L. leaves. Different drying carriers, namely, maltodextrin, colloidal silicon dioxide, Arabic gum, and β-cyclodextrin at concentrations of 40 and 80% relative to solids content, were added to drying composition. SDE were characterized through determination of the total phenolic, tannins, and flavonoid content. Antioxidant potential of the SDE was assessed by two assays: cellular test that measures the luminol-enhanced chemiluminescence (LumCL produced by neutrophils stimulated with phorbol myristate acetate (PMA and the DPPH radical scavenging (DPPH* method. In both assays the antioxidant activity of the SDE occurred in a concentration-dependent manner and showed no toxicity to the cells. Using the CLlum method, the IC50 ranged from 5.42 to 6.50 µg/mL. The IC50 of the SDE ranged from 7.96 to 8.11 µg/mL using the DPPH• method. Psidium guajava SDE presented significant antioxidant activity; thus they show high potential as an active phytopharmaceutical ingredient. Our findings in human neutrophils are pharmacologically relevant since they indicate that P. guajava SDE is a potential antioxidant and anti-inflammatory agent in human cells.

  20. In vitro and In vivo evaluation of free radical scavenging potential of ...

    African Journals Online (AJOL)

    The present study was performed to evaluate the effect of the methanolic extract of Cissus quadrangularis (CQE) against free radical damage. The test extract exhibited significant inhibition in DPPH free radical formation, superoxide radical production and lipid peroxide production in erythrocytes. The activities of liver ...

  1. Biochemical characterization of radical scavenging polyphenols from Nyctanthes arbortristis.

    Science.gov (United States)

    Meghashri, S; Gopal, S

    2012-10-01

    Antioxidants are quenchers of free radical that are responsible for inducing oxidative stress generated via reactive oxygen species-induced degenerative diseases such as cancer, diabetes, and cardiovascular diseases etc. Plant and plant products are recognized as safe and potential health promoting and nutritive sources. To investigate the antioxidant potency of polyphenol extract (PE) of Nyctanthes arbortristis leaves and identification of the active constituent by HPLC. PE of N. arbortristis leaves was investigated for antioxidant activity employing various established in vitro systems, such as lipid peroxidation in liposome, DPPH and hydroxyl radical scavenging, reducing power assay, and iron ion chelation. Identification of active constituent in PE of N. arbortristis responsible for antioxidant activity by HPLC. All experiments were carried out in triplicates. Data were shown as mean ± standard deviation (SD). SPSS 10.0.5 version for windows (SPSS software Inc., USA) computer program was used for statistical analysis. Identification of active constituent in PE revealed gallic acid 75.8 ± 0.21, protocatechuic acid 14.6 ± 0.5, chlorogenic acid 6.79 ± 0.43, and caffeic acid 5.34 ± 0.2 μg/ml. PE showed strong inhibitory activity of 73% at 200 μg/ml toward lipid peroxidation in egg lecithin, concentration-dependent inhibition of deoxyribose oxidation at 200 μg/ml was 85% inhibition, and considerable antioxidant activity in DPPH radical assay system at 200 μg/ml was 79% inhibition. BHA and gallic acid showed significant observations. The antioxidant potency significantly correlated with the phenolic content of PE. Considering that medicinal herbs contain potent phytochemicals, which is effectively utilized for various degenerative disease, these in vitro results showed that N. arbortristis leaves could be effectively employed in functional food, to alleviate oxidative stress.

  2. Biochemical characterization of radical scavenging polyphenols from Nyctanthes arbortristis

    Directory of Open Access Journals (Sweden)

    S Meghashri

    2012-01-01

    Full Text Available Context: Antioxidants are quenchers of free radical that are responsible for inducing oxidative stress generated via reactive oxygen species-induced degenerative diseases such as cancer, diabetes, and cardiovascular diseases etc. Plant and plant products are recognized as safe and potential health promoting and nutritive sources. Aims: To investigate the antioxidant potency of polyphenol extract (PE of Nyctanthes arbortristis leaves and identification of the active constituent by HPLC. Materials and Methods: PE of N. arbortristis leaves was investigated for antioxidant activity employing various established in vitro systems, such as lipid peroxidation in liposome, DPPH and hydroxyl radical scavenging, reducing power assay, and iron ion chelation. Identification of active constituent in PE of N. arbortristis responsible for antioxidant activity by HPLC. Statistical analysis used: All experiments were carried out in triplicates. Data were shown as mean ± standard deviation (SD. SPSS 10.0.5 version for windows (SPSS software Inc., USA computer program was used for statistical analysis. Results: Identification of active constituent in PE revealed gallic acid 75.8 ± 0.21, protocatechuic acid 14.6 ± 0.5, chlorogenic acid 6.79 ± 0.43, and caffeic acid 5.34 ± 0.2 μg/ml. PE showed strong inhibitory activity of 73% at 200 μg/ml toward lipid peroxidation in egg lecithin, concentration-dependent inhibition of deoxyribose oxidation at 200 μg/ml was 85% inhibition, and considerable antioxidant activity in DPPH radical assay system at 200 μg/ml was 79% inhibition. BHA and gallic acid showed significant observations. Conclusion: The antioxidant potency significantly correlated with the phenolic content of PE. Considering that medicinal herbs contain potent phytochemicals, which is effectively utilized for various degenerative disease, these in vitro results showed that N. arbortristis leaves could be effectively employed in functional food, to

  3. Screening of radical scavenging activity of some medicinal and aromatic plant extracts

    NARCIS (Netherlands)

    Miliauskas, G.; Venskutonis, R.P.; Beek, van T.A.

    2004-01-01

    Extracts of 12 medicinal and aromatic plants were investigated for their radical scavenging activity using DPPH and ABTS assays: Salvia sclarea, Salvia glutinosa, Salvia pratensis, Lavandula angustifolia, Calendula officinalis, Matricaria recutita, Echinacea purpurea, Rhaponticum carthamoides,

  4. Total antioxidant potential of juices, beverages and hot drinks consumed in Egypt screened by DPPH in vitro assay

    Directory of Open Access Journals (Sweden)

    Ramadan-Hassanien, Mohamed Fawzy

    2008-09-01

    Full Text Available Plant foods contain different classes and types of antioxidants and knowledge of their total antioxidant potential (TAP, which is the cumulative capacity of food components to scavenge free radicals, would be useful for epidemiological purposes.To accomplish this, a variety of fruit juices, hot drinks and beverages commonly consumed in Egypt were analyzed using in vitro DPPH assay. The order of effectiveness of fruit juices in inhibiting free radicals was as follows: red grapes juice > mango juice > guava juice > cocktail juice > pineapple juice > orange juice > cherry juice > apple juice. Among beverages and hot drinks, teas followed by coffees had the greatest TAP. These data confirm grape juice, teas and coffees as good dietary sources of antioxidants.Las plantas comestibles contienen diferentes clases y tipos de antioxidantes y el conocimiento de su potencial antioxidante total (TAP, que es la capacidad acumulativa de los componentes de los alimentos para captar radicales libres, debería ser útil en estudios epidemiológicos. De acuerdo a esto, una variedad de zumos de fruta, bebidas calientes y bebidas consumidas habitualmente en Egipto fueron analizadas usando un ensayo in vitro con DPPH. El orden de efectividad de los zumos de frutas en inhibir los radicales libres fue el siguiente: zumo de uva tinta > zumo de mango > zumo de guayaba > zumo de macedonia de frutas > zumo de piña >zumo de naranja > zumo de cereza > zumo de manzana. Entre las bebidas y bebidas calientes, el té seguido por el café son los que tuvieron mayores TAPs. Estos datos confirman que el zumo de uva, el té y el café son buenas fuentes de antioxidantes.

  5. Radical scavenging, antioxidant and cytotoxic activity of Brazilian Caatinga plants.

    Science.gov (United States)

    David, Juceni P; Meira, Marilena; David, Jorge M; Brandão, Hugo N; Branco, Alexsandro; de Fátima Agra, M; Barbosa, M Regina V; de Queiroz, Luciano P; Giulietti, Ana M

    2007-04-01

    Extracts of 32 plants from the Brazilian northeastern semi-arid region called Caatinga were evaluated through DPPH radical scavenging assay, beta-carotene bleaching, and brine shrimp lethality tests (BST). Among the extracts studied Byrsonima cf. gardneriana, Mascagnia coriacea, Cordia globosa, Diodia apiculata and Hypenia salzmannii showed the highest activities in DPPH radical scavenging test. In the beta-carotene bleaching test the highest activities were observed for Passiflora cincinnata, Chamaecrista repens, B. cf. gardneriana, Rollinia leptopetala, Serjania glabrata, Diospyros gaultheriifolia, C. globosa, Mimosa ophtalmocentra, M. coriacea and Lippia cf. microphylla. In contrast, R. leptopetala, Zornia cf. brasiliensis and Leonotis nepetifolia were the most active species in the BST.

  6. UJI AKTIVITAS ANTIOKSIDAN DAN PENETAPAN KADAR FENOLAT TOTAL FRAKSI AIR DAUN KETAPANG (Terminalia catappa L. DENGAN METODE DPPH (2,2-diphenyl-1-picrylhydrazyl DAN METODE FOLIN-CIOCALTEU

    Directory of Open Access Journals (Sweden)

    Aldo Sahala

    2012-11-01

    Full Text Available Abstract: The aqueous fraction of methanolic extract of Ketapang (Terminalia catappa L.. was investigated for its DPPH (2,2-diphenyl-1-picrylhydrazyl free radical scavenger activity and the total amount of phenolic using Folin-Ciocalteu method. It was found that the aqueous fraction of methanolic extract of Ketapang tested showed significant DPPH free radicalscavenging with IC50 value 34,071 ± 0,424 µg/mL. The total phenolic amount was 5.429 ± 0.110 mg equivalent mass value of gallic acid per gram aqueous fraction of the methanolic extract of ketapang leaves. Keywords: aqueous fraction, methanolic extract, Terminalia catappa, DPPH, total phenolic.

  7. cis-Thioindigo (TI) - a new ligand with accessible radical anion and dianion states. Strong magnetic coupling in the {[TI-(μ2-O),(μ-O)]Cp*Cr}2 dimers.

    Science.gov (United States)

    Konarev, Dmitri V; Khasanov, Salavat S; Shestakov, Alexander F; Fatalov, Alexey M; Batov, Mikhail S; Otsuka, Akihiro; Yamochi, Hideki; Kitagawa, Hiroshi; Lyubovskaya, Rimma N

    2017-10-24

    Reaction of decamethylchromocene (Cp* 2 Cr) with thioindigo (TI) yields a coordination complex {[TI-(μ 2 -O), (μ-O)]Cp*Cr} 2 ·C 6 H 14 (1) in which one Cp* ligand in Cp* 2 Cr is substituted by TI. TI adopts cis-conformation in 1 allowing the coordination of both carbonyl groups to chromium. Additionally, one oxygen atom of TI becomes a μ 2 -bridge for two chromium atoms to form {[TI-(μ 2 -O), (μ-O)]Cp*Cr} 2 dimers with a CrCr distance of 3.12 Å. According to magnetic data, diamagnetic TI 2- dianions and two Cr 3+ atoms with a high S = 3/2 spin state are present in a dimer allowing strong antiferromagnetic coupling between two Cr 3+ spins with an exchange interaction of -35.4 K and the decrease of molar magnetic susceptibility below 140 K. Paramagnetic TI˙ - radical anions with the S = 1/2 spin state have also been obtained and studied in crystalline {cryptand[2,2,2](Na + )}(TI˙ - ) (2) salt showing that both radical anion and dianion states are accessible for TI.

  8. Free radical scavenging properties of some wine probes

    International Nuclear Information System (INIS)

    Stasko, A.; Liptakova, M.; Malik, F.

    1999-01-01

    There are preliminary results of investigation of scavenging properties of 8 probes of Slovak wines (consisting of one reference, 3 probes of white wine and 4 probes of red wine). According to the literature so far, wine probes contain paramagnetic species (Mn 2+ , characterised with sextet spectrum, and a singlet line around g=2,00). In our probes we observed Mn 2+ signals, but no significant evidence for a single line of free radical was found. We can conclude that Mn 2+ content in the red wines is generally higher than in the white ones. Further, we investigated the scavenging activities of the probes adding solution of dinitropicryl hydrazyl (DPPH-stable radical) to them. Their ability to terminate free radicals resulted in the decrease of the final DPPH concentrations in the probes. The red wines have significantly higher capability to scavenge free radicals than the probes of white wines. (authors)

  9. Evaluation of antimalarial, free-radical-scavenging and insecticidal activities of Artemisia scoparia and A. Spicigera, Asteraceae

    Directory of Open Access Journals (Sweden)

    Fariba H. Afshar

    2011-12-01

    Full Text Available Artemisia species (Asteraceae, widespread throughout the world, are a group of important medicinal plants. The extracts of two medicinal plants of this genus, Artemisia scoparia Waldst. & Kit. and A. spicigera C. Koch, were evaluated for potential antimalarial, free-radical-scavenging and insecticidal properties, using the heme biocrystallisation and inhibition assay, the DPPH assay and the contact toxicity bioassay using the pest Tribolium castaneum, respectively. The methanol extracts of both species showed strong free-radical-scavenging activity and the RC50 values were 0.0317 and 0.0458 mg/mL, respectively, for A. scoparia and A. spicigera. The dichloromethane extracts of both species displayed a moderate level of potential antimalarial activity providing IC50 at 0.778 and 0.999 mg/mL for A. scoparia and A. spicigera, respectively. Both species of Artemisia showed insecticidal properties. However, A. spicigera was more effective than A. scoparia.

  10. Free radical-scavenging and antimutagenic potential of acetone ...

    African Journals Online (AJOL)

    The antioxidant potency of acetone, chloroform and methanol extracts of Argemone mexicana was investigated by employing in vitro systems like nitroblue tetrazolium (NBT) and 1,1-Diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging assay whereas antimutagenic activity was determined by Maron and Ames assay ...

  11. Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris Leaves

    NARCIS (Netherlands)

    Dapkevicius, A.; Beek, van T.A.; Lelyveld, G.P.; Veldhuizen, van A.; Groot, de Æ.; Linssen, J.P.H.; Venskutonis, R.

    2002-01-01

    2,2-Diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity-guided fractionation of a leaf extract of Thymus vulgaris led to the isolation of the radical scavengers rosmarinic acid 1, eriodictyol, taxifolin, luteolin 7-glucuronide, p-cymene 2,3-diol, p-cymene 2,3-diol 6-6'-dimer, carvacrol,

  12. Comparative Evaluation of the Radical-Scavenging Activities of Fucoxanthin and Its Stereoisomers

    Directory of Open Access Journals (Sweden)

    Yiping Zhang

    2014-02-01

    Full Text Available Fucoxanthin (Fuco is a characteristic carotenoid of brown seaweeds. In the present study, Fuco and its stereoisomers 9'Z-Fuco, 13Z- and 13'Z-Fuco were extracted from Laminaria japonica Aresch. They were isolated and purified by silica gel column chromatography, Sephadex LH-20, and reversed-phase HPLC. The radical-scavenging activities of the three stereoisomers were evaluated toward 1,1-diphenyl-2-picrylhydrazyl (DPPH radical, 2-2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS radical, hydroxyl radical, and superoxide radical. The order of 1,1-diphenyl-2-picrylhydrazyl (DPPH radical-scavenging activity was 13Z- and 13'Z-Fuco > (all-E-Fuco > 9'Z-Fuco. The order of 2-2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS and hydroxyl radical-scavenging activities were 9'Z-Fuco > (all-E-Fuco > 13Z-and 13'Z-Fuco. The order of superoxide radical-scavenging activity was 13Z- and 13'Z-Fuco > (all-E-Fuco > 9'Z-Fuco. The scavenging activities of Fuco and its stereoisomers toward the four radical types were all dose-dependent. The ABTS, DPPH, and superoxide radical-scavenging activities were all weaker than that of tocopherol (VE, while their hydroxyl radical-scavenging activities were stronger than that of VE. The results confirmed that Fuco and its stereoisomers have potent antioxidant activities.

  13. Cytotoxic and free radical scavenging activities of Zingiberaceous rhizomes

    Directory of Open Access Journals (Sweden)

    Niwat Keawpradub

    2005-07-01

    Full Text Available Methanol extracts, water extracts and volatile oils of the fresh rhizomes of Alpinia galanga, Boesenbergia pandurata, Curcuma longa, Kaempferia galanga and Zingiber officinale have been assessed for free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH radical and cytotoxic activity against MCF7 (breast adenocarcinoma and LS174T (colon adenocarcinoma cell lines. Methanol extract of C. longa exhibited the most pronounced radical scavenging activity with an EC50 value of 9.7 μg/ml, whereas the water extracts and volatile oils showed weak activity. All volatile oils and the methanol extract of C. longa showed strong activity against MCF7 and LS174T with IC50 less than 50 μg/ml. The oils of A. galanga (AGV, B. pandurata (BPV, C. longa (CLV, K. galanga (KGV and Z. officinale (ZOV were analyzed by GC/MS. Trans-3-acetoxy-1,8-cineole, camphor, ar-turmerone, ethyl cinnamate and geranial (E-citral were detected as main compounds in AGV, BPV, CLV, KGV and ZOV, respectively. The novel compound, pcoumaryl- 9-methyl ether, was isolated from methanol extract of A. galanga. ar-Turmerone, curcumin, demethoxycurcumin and bisdemethoxycurcumin were isolated from the methanol extract of C. longa while 6-shogaol, 6-dehydrogingerdione (or 1-dehydrogingerdione and 6-gingerol were isolated from the methanol extract of Z. officinale. Curcumin was the most potent compound for free radical scavenging activity with an EC50 value of 2.0 μg/ml. Demethoxycurcumin was found to be the most active compound against LS174T with an IC50 value of 0.8 μg/ml and 6-shogaol was the most potent compound against MCF7 with an IC50 value of 1.7 μg/ml.

  14. Study of Antioxidant and Free Radical Scavenging Activities of Cotoneaster medicus and Glycyrrhiza glabra Plants

    Directory of Open Access Journals (Sweden)

    M. M. Heravi

    2013-08-01

    Full Text Available Extracts of Cotoneaster medicus, Glycyrrhiza glabra, as endemic plants of Iran, along with mixture of them were investigated for their antioxidant activities using 2, 2- diphenyl-1-picrylhidrazyl (DPPH reagent. UV-Vis spectrophotometry method was used to evaluate the ability of Cotoneaster and Glycyrrhiza glabra antioxidant to scavenge DPPH radical. The kinetic parameters such as rate constant and activation energy in experimental conditions were calculated. The rate constants of the H atom abstraction by DPPH (k1, in the presence of C. medicus and G. glabra antioxidant were obtained under pseudo-first-order conditions at different temperatures. The order in DPPH radical-scavenging was: mixture of C. medicus and G. glabra > C. medicus > G.  glabra plants. The numerical values of activation energy were found to be 45.84 kJ.mol-1for G. glabra and 62.02kJ.mol-1 for C. medicus.

  15. Development of a triple hyphenated HPLC-radical scavenging detection-DAD-SPE-NMR system for the rapid identification of antioxidants in complex plant extracts

    NARCIS (Netherlands)

    Pukalskas, A.; Beek, van T.A.; Waard, de P.

    2005-01-01

    A rapid method for the simultaneous detection and identification of radical scavenging compounds in plant extracts was developed by combining an HPLC with on-line radical scavenging using DPPH as a model radical and an HPLC¿DAD¿SPE¿NMR system. Using this method a commercial rosemary extract was

  16. Effect of ultraviolet irradiation on free radical scavenging activity of immunosuppressants used in lung transplantation and comparative electron paramagnetic resonance study of kinetics of their interactions with model free radicals.

    Science.gov (United States)

    Stanjek-Cichoracka, A; Żegleń, S; Ramos, P; Pilawa, B; Wojarski, J

    2018-01-27

    The immunosuppressive drugs used in solid organ transplantation or autoimmunological processes were studied by electron paramagnetic resonance (EPR) spectroscopy to estimate their free radical scavenging activity. The interactions of immunosuppressants with free radicals were examined by an X-band (9.3 GHz) EPR spectroscopy and a model of DPPH free radicals. The EPR spectra of DPPH and DPPH interacting with individual drugs were compared. Kinetic studies were performed, and the effect of ultraviolet (UV) irradiation on the free radical scavenging activity of the tested drugs was determined. The free radical scavenging activity of non-irradiated drugs decreased in the order: rapamycin > mycophenolate mofetil > ciclosporin > tacrolimus. UV irradiation increased the free radical scavenging activity of all the tested immunosuppressive drugs, and the effect was highest for tacrolimus. For the non-irradiated samples, the speed of free radical interactions decreased in the order: ciclosporin > tacrolimus > mycophenolate mofetil > rapamycin. UV irradiation only slightly affected the speed of interactions of the immunosuppressive drugs with the model DPPH free radicals. Electron paramagnetic resonance spectroscopy is useful for obtaining information on interactions of immunosuppressive drugs with free radicals. We hypothesized that the long-term immunosuppressive effects of these drugs after transplantation or during autoimmune disorders may be mediated by anti-inflammatory action in addition to the known receptor/cell cycle inhibition. © 2018 John Wiley & Sons Ltd.

  17. Evaluation of free radical scavenging capacity and antioxidative damage effect of resveratrol-nanostructured lipid carriers

    Science.gov (United States)

    Jin, Ju; Shi, Fan; Li, Qiu-wen; Li, Pei-shan; Chen, Tong-sheng; Wang, Yi-fei; Wang, Zhi-ping

    2016-03-01

    Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical(ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, resveratrol loaded nanostructured lipid carriers (Res-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Res-NLC on free radical scavenging capacity and antioxidative damage is investigated. The particle size and zeta potential of Res-NLC were 139.3 ± 1.7 nm and -11.21 ± 0.41 mV, respectively. By free radical scavenging assays, the IC50 value of Res-NLC were 19.25, 5.29 μg/mL with DPPH, ABTS assay respectively, and 0.161 mg ferrous sulfate/1 mg Res-NLC with FRAP assay; and by AAPH-induced oxidative injury cell model assay, Res-NLC showed the strong protective effect against the human liver tumor HepG2 cell oxidative stress damage. These results indicated that the antioxidant properties of Res-NLC hold great potential used as an alternative to more toxic synthetic antioxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

  18. Free radical-scavenging delta-lactones from Boletus calopus.

    Science.gov (United States)

    Kim, Jin-Woo; Yoo, Ick-Dong; Kim, Won-Gon

    2006-12-01

    The methanol extracts from the fruiting body of the mushroom Boletus calopus showed free radical-scavenging activity. Bioactivity-guided fractionation of the methanol extracts led to a new hydroxylated calopin named calopin B, along with the known delta-lactones calopin and cyclocalopin A. The structure of the new calopin analogue was elucidated by spectroscopic methods. All compounds showed potent free radical-scavenging activity against superoxide, DPPH, and ABTS radicals with IC (50) values of 1.2 - 5.4 microg/mL.

  19. Rapid Identification and Quantification of Natural Antioxidants in the Seeds of Rhubarb from Different Habitats in China Using Accelerated Solvent Extraction and HPLC-DAD-ESI-MSn-DPPH Assay.

    Science.gov (United States)

    Tan, Liang; Geng, Dan-dan; Hu, Feng-zu; Dong, Qi

    2016-01-01

    In this study, the 10 accessions of rhubarb seeds from different habitats in China were investigated. Lipids were removed using petroleum ether, and the effective components were then separated using accelerated solvent extraction with 80% aqueous methanol. An off-line 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging method was used as the marker to evaluate the total antioxidant capability of extracts. On-line high-performance liquid chromatography-diode-array detectors-electrospray ionization-tandem mass spectrometry (HPLC-DAD-ESI-MS(n)) and HPLC-DAD-DPPH assays were developed for rapid identification and quantification of individual free-radical scavengers in extracts of rhubarb seeds. Ten free-radical scavengers from methanolic extracts of the rhubarb seeds were screened, five of which were identified and quantitatively analyzed: epicatechin, myricetin, hyperoside, quercitrin and quercetin. All were identified in rhubarb seeds for the first time and can be regarded as the major potent antioxidants in rhubarb seeds due to representing most of the total free-radical scavenging activity. Preliminary analysis of structures was performed for another five antioxidants. Based on our validation results, the developed method can be used for rapid separation, convenient identification and quantification of the multiple antioxidative constituents in rhubarb seeds, featuring good quantification parameters, accuracy and precision. The results are important to clarify the material basis and therapeutic mechanism of rhubarb seeds. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Interaction of gold nanoparticles with free radicals and their role in enhancing the scavenging activity of ascorbic acid.

    Science.gov (United States)

    Razzaq, Humaira; Saira, Farhat; Yaqub, Azra; Qureshi, Rumana; Mumtaz, Misbah; Saleemi, Samia

    2016-08-01

    The present study investigates the interaction of citrate stabilized gold nanoparticles (12±1.5nm) (GNPs) with free radicals; 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable and electrochemically generated superoxide, O2(-). Different experiments were designed to understand the interaction between GNPs and DPPH by employing cyclic voltammetry, UV-vis spectroscopy and computational chemistry using 6-311G basis set. The increase in heterogeneous rate constant, ksh, of DPPH upon addition of GNPs pointed towards possible complex formation, DPPH-GNPs which were further explained by a model assuming surface adsorption of DPPH on GNPs. Further, the model was validated by studying interaction of GNPs with a biologically important free radical, O2(-). Exciting result in terms of disappearance of anodic peak after GNPs addition confirmed that gold nanoparticles interacted with stable as well as unstable free radicals. Also, the stoichiometry of the most stable complex GNP-DPPH was determined from UV-vis spectroscopy by applying Job's method. The GNP-DPPH complex was found to be active with 46.0% reduction of the IC50 value of standard antioxidant, ascorbic acid (AA), indicating its role in enhancing antioxidant activity. Hence, this study presents a simple and potential approach to enhance the efficiency of natural antioxidants without modifying their structure, or involving the complex functionalization of GNPs with antioxidants. Copyright © 2016. Published by Elsevier B.V.

  1. Analisis Antioksidan Ekstrak Etil Asetat Dari Kulit Buah Rambutan (Nephelium Lappaceum dengan Menggunakan Metode dpph (1,1 difenil-2-pikrilhidrakzil

    Directory of Open Access Journals (Sweden)

    Nurfadillah Nurfadillah

    2016-01-01

    Full Text Available Rapiah rambutan fruit leather (Nephelium lappaceum is one of the traditional medicine to cure various diseases such as fever and dysentery. Scientific research previously stated rambutan fruit peel skin Rapiah rambutan (Nephelium lappaceum potentially have antioxidant content. Through this research can know the effect of solvent ethyl acetate to extract optimal rambutan fruit skin in antioxidants withdrawal. The method used for extraction is macerated using methanol and partitioned with liquid-liquid extraction using ethyl acetate solvent with a ratio (1:3, (1:4 and (1:5 which produces a thick rind extract rambutan. The extract was tested color and separated by thin layer chromatography (TLC using the eluent butanol: glacial acetic acid: water (BAA (4: 1: 5. Antioxidants are determined by testing against DPPH free radicals by measuring the absorbance of DPPH (1,1-diphenyl-2-pikrilhidraksil at a wavelength of 517 nm. So that the results of this study showed the highest % reduction obtained at a ratio (1:3.

  2. Effects on DPPH inhibition of egg-white protein polypeptides treated by pulsed electric field technology.

    Science.gov (United States)

    Wang, Ke; Wang, Jia; Liu, Bolong; Lin, Songyi; Zhao, Ping; Liu, Jingbo; Jones, Gregory; Huang, Hsiang-Chi

    2013-05-01

    Egg-white protein polypeptides are potentially used as a functional ingredient in food products. In this study, the effects on DPPH inhibition of egg-white protein polypeptides ranging from 10 to 30 kDa treated by pulsed electric field (PEF) technology were investigated. 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) inhibition (%) was used to evaluate the antioxidant activity of polypeptides. In order to develop and optimize a pulsed electric field (PEF) mathematical model for improving the antioxidant activity, we have investigated three variables, including concentration (6, 8 and 10 mg mL(-1)), electric field intensity (10, 20 and 30 kV cm(-1)) and pulse frequency (2000, 2350 and 2700 Hz) and subsequently optimized them by response surface methodology (RSM). The concentration (8 mg mL(-1)), electric field intensity (10 kV cm(-1)) and pulse frequency (2000 Hz) were found to be the optimal conditions under which the DPPH inhibition increased 28.44%, compared to the sample without PEF treatment. Both near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyze the change of functional groups. The results showed that PEF technology could improve the antioxidant activity of antioxidant polypeptides from egg-white protein under the optimized conditions. © 2012 Society of Chemical Industry.

  3. Oxygen free radicals in rheumatoid arthritis

    NARCIS (Netherlands)

    P. Biemond (Pieter)

    1986-01-01

    textabstractCurrent knowledge strongly suggests that oxygen free radicals are involved in the pathogenesis of RA. Additional information about the mechanism of free radical attack is necessary in order to find out if interaction with the mechanism of free radical damage can be used in the treatment

  4. Antioxidant and free radical scavenging activities of some medicinal plants from the Lamiaceae.

    Science.gov (United States)

    Matkowski, Adam; Piotrowska, Magdalena

    2006-07-01

    Antioxidative effects of methanolic extracts from six wild European Lamiaceae species have been studied with the use of three in vitro assays. The ability of scavenging free radicals was measured by DPPH reduction spectrophotometric assay. The reducing potential towards transition metals was tested by phosphomolybdenum method and the inhibition of lipid oxidation was tested by Fe/ascorbate system with photometric TBARS detection. All studied herbs exposed strong antioxidant capability, but the results were different for each species depending on the applied test. In DPPH scavenging the order from strongest to the weakest was: Leonurus cardiaca, Lamium album, Marrubium vulgare, Stachys officinalis, Lamium purpureum, Galeopsis speciosa. With phosphomolybdenum method the extract of S. officinalis was the strongest in both 40 degrees Celsius and 90 degrees Celsius but other species acted differently in both temperatures. In lipid peroxidation assay, the maximum inhibition of 78% was reached by S. officinalis and M. vulgare, whereas for both Lamium sp. and L. cardiaca slightly exceeded 70% and for G. speciosa reached 65%. The observed differences indicate the complexity of involved mechanisms and support the necessity of combining several assays in studying the antioxidant potential of medicinal plants.

  5. Extracts, Anthocyanins and Procyanidins from Aronia melanocarpa as Radical Scavengers and Enzyme Inhibitors

    Directory of Open Access Journals (Sweden)

    Hilde Barsett

    2013-03-01

    Full Text Available Extracts, subfractions, isolated anthocyanins and isolated procyanidins B2, B5 and C1 from the berries and bark of Aronia melanocarpa were investigated for their antioxidant and enzyme inhibitory activities. Four different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH radical, inhibition of 15-lipoxygenase (15-LO, inhibition of xanthine oxidase (XO and inhibition of α-glucosidase. Among the anthocyanins, cyanidin 3-arabinoside possessed the strongest and cyanidin 3-xyloside the weakest radical scavenging and enzyme inhibitory activity. These effects seem to be influenced by the sugar units linked to the anthocyanidin. Subfractions enriched in procyanidins were found to be potent α-glucosidase inhibitors; they possessed high radical scavenging properties, strong inhibitory activity towards 15-LO and moderate inhibitory activity towards XO. Trimeric procyanidin C1 showed higher activity in the biological assays compared to the dimeric procyanidins B2 and B5. This study suggests that different polyphenolic compounds of A. melanocarpa can have beneficial effects in reducing blood glucose levels due to inhibition of α-glucosidase and may have a potential to alleviate oxidative stress.

  6. Radical-scavenging Activity of Natural Methoxyphenols vs. Synthetic Ones using the Induction Period Method

    Directory of Open Access Journals (Sweden)

    Seiichiro Fujisawa

    2007-02-01

    Full Text Available The radical-scavenging activities of the synthetic antioxidants 2-allyl-4-X-phenol (X=NO2, Cl, Br, OCH3, COCH3, CH3, t-(CH33, C6H5 and 2,4-dimethoxyphenol, and the natural antioxidants eugenol and isoeugenol, were investigated using differential scanning calorimetry (DSC by measuring their anti-1,1-diphenyl-2-picrylhydrazyl (DPPH radical activity and the induction period for polymerization of methyl methacrylate (MMA initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN and benzoyl peroxide (BPO. 2-Allyl-4-methoxyphenol and 2,4-dimethoxy-phenol scavenged not only oxygen-centered radicals (PhCOO. derived from BPO, but also carbon-centered radicals (R. derived from the AIBN and DPPH radical much more efficiently, in comparison with eugenol and isoeugenol. 2-Allyl-4-methoxyphenol may be useful for its lower prooxidative activity.

  7. AVALIAÇÃO DA ATIVIDADE ANTIOXIDANTE DE DIFERENTES CERVEJAS APLICANDO OS MÉTODOS ABTS E DPPH

    Directory of Open Access Journals (Sweden)

    G. L. FREITAS

    2009-01-01

    Full Text Available

    Os compostos fenólicos são substâncias presentes naturalmente nos vegetais que podem atuar como antioxidantes. Na cerveja desempenham um papel importante nas características sensoriais (cor, aroma e sabor e nutricionais da cerveja. O objetivo deste trabalho foi determinar o conteúdo de compostos fenólicos totais e flavonóis em diversos tipos de cervejas comercializada no Brasil, assim como determinar a capacidade antioxidante in vitro realizada por dois métodos, o radical ABTS•+ (ácido 2,2'-azino-bis (3-etilbenzotiazolin 6-sulfônico e o radical DPPH• (2,2-Difenil-1-picrilhidrazilo. Para determinar os polifenóis totais foi utilizado o método de Folin-Ciocalteau e o método DMACA para os flavanóis. Os resultados mostraram que o conteúdo de compostos fenólicos nas cervejas analisadas variou de 249,73 ± 8,44 a 808,58 ± 7,42 mg/L. A cerveja escura de trigo, apresentou os maiores valores de polifenóis totais, seguida das cervejas escura de cevada, da clara de trigo e das cervejas clara de cevada. Foram encontrados resultados significativos para atividade antioxidante aplicando o método ABTS, valores de 911,79 ± 2,21 a 3857,66 ± 6,07 Mol TEAC/L dependendo do tipo de cerveja e pelo método DPPH, de 2840,12 ± 1,09 a 4290,77± 6,19 Mol TEAC/L. O conteúdo de flavanóis (equivalente a mg catequina/L de amostra., variaram em média de 1,93 ± 0,07 mg/L a 2,79 ± 0,08 mg/L para as cervejas claras e de 2,14 ± 0,04 mg/L a 5,09 ± 0,08 mg/L para as cervejas escuras.

  8. Radical Islam

    Science.gov (United States)

    2002-07-01

    Muslim insurgents have a real following in many countries. In Mao’s parlance, the radical Muslim insurgent is the fish swimming in the ocean of the...indigenous beliefs 5% Tanzania: mainland - Christian 45%, Muslim 35%, indigenous beliefs 20%; Zanzibar - more than 99% Muslim Zambia: Christian 50...leather, frozen fish and seafood Bosnia and Herzegovina NA Brunei: crude oil, natural gas, refined products Chad: cotton, cattle, textiles Cocos Islands

  9. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  10. The antioxidant activity test by using DPPH method from the white tea using different solvents

    Science.gov (United States)

    Darmajana, Doddy A.; Hadiansyah, Firman; Desnilasari, Dewi

    2017-11-01

    The solvents used in this study are: aquades, ethanol and glacial acetic acid. The raw material as the source of antioxidants is white tea. Pure Quercetin is used as a comparing antioxidant. The treatment design was the solvent type for extraction, while the antioxidant activity was tested using DPPH method, with IC50 as the reference of antioxidant activity value. The results of antioxidant activity tests with three different solvent types are IC50 of 22,499 µg/mL for aquades, IC50 of 13,317 µg/mL for Ethanol and IC50 of 60,555 µg/mL for Glacial Acetic Acid. As a control of the standard antioxidant activity value of Quercetin is 4,313 µg/mL.

  11. Preliminary assay on the radical scavenging activity of olive wood extracts

    NARCIS (Netherlands)

    Altarejos, J.; Salido, S.; Pérez-Bonilla, M.; Linares-Palomino, P.J.; Beek, van T.A.; Nogueras, M.; Sánchez, A.

    2005-01-01

    The dichloromethane and ethanol extracts of Olea europaea wood (picual olive cultivar) were screened for antioxidant activity, determined by the DPPH free radical scavenging assay. The ethanol extract displayed potent antioxidant activity. (c) 2005 Elsevier B.V. All rights reserved.

  12. Beta-carotene encapsulated in food protein nanoparticles reduces peroxyl radical oxidation in Caco-2 cells

    Science.gov (United States)

    Beta-carotene (BC) was encapsulated by sodium caseinate (SC), whey protein isolate (WPI), and soybean protein isolate (SPI) by the homogenization-evaporation method forming nanoparticles of 78, 90 and 370 nm diameter. Indices of the chemical antioxidant assays, the reducing power, DPPH radical scave...

  13. In vitro anti-inflammatory and free radical scavenging activities of ...

    African Journals Online (AJOL)

    The antiinflammatory potential was carried out using inhibition of protein denaturation of egg albumin as a model of anti-inflammatory capacity. Results: Both the crude methanolic extract and saponins showed inhibition of DPPH, ABTS and NO2 scavenging activity. However, the free radical scavenging activity of isolated ...

  14. Development of nitroxide radicals-containing polymer for scavenging reactive oxygen species from cigarette smoke

    Science.gov (United States)

    Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

    2014-06-01

    We developed a nitroxide radicals-containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV-visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke.

  15. Preparative isolation and purification of seven main antioxidants from Eucommia ulmoides Oliv. (Du-zhong) leaves using HSCCC guided by DPPH-HPLC experiment.

    Science.gov (United States)

    Dai, Xingping; Huang, Qiong; Zhou, Boting; Gong, Zhicheng; Liu, Zhaoqian; Shi, Shuyun

    2013-08-15

    Seven antioxidants were purified from Eucommia ulmoides Oliv. leaves using HSCCC guided by DPPH-HPLC experiment. HSCCC was successfully used to separate target antioxidants by three runs with different solvent systems after D101 column chromatography fractionation. Ethyl acetate-n-butanol-water (1:2:3, v/v/v) was selected as the optimum solvent system to purify geniposidic acid. Ethyl acetate-ethanol-water (4:1:5, v/v/v) was used to isolate caffeic acid, chlorogenic acid and ferulic acid. While three flavonoids, quercetin-3-O-sambubioside, rutin and isoquercitrin were purified by petroleum ether-ethyl acetate-methanol-water (1:5:1:5, v/v/v/v). The structures were identified by MS and NMR. Antioxidant activities were assessed, and compounds 2-7 showed strong antioxidant activities. This is the first report about separation of antioxidants from E. ulmoides leaves by HSCCC. The results indicated that the combinative methods using DPPH-HPLC and HSCCC could be widely applied for screening and isolation of antioxidants from complex extracts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. High-performance liquid chromatographic method to evaluate the hydrogen atom transfer during reaction between 1,1-diphenyl-2-picryl-hydrazyl radical and antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Boudier, Ariane; Tournebize, Juliana [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France); Bartosz, Grzegorz [Department of Molecular Biophysics, University of Lodz, Lodz (Poland); El Hani, Safae; Bengueddour, Rachid [Laboratoire de Nutrition et Sante, Biology Department, Faculty of Sciences, Ibn Tofail University, Kenitra (Morocco); Sapin-Minet, Anne [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France); Leroy, Pierre, E-mail: pierre.leroy@pharma.uhp-nancy.fr [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France)

    2012-01-20

    Highlights: Black-Right-Pointing-Pointer Both 1,1-diphenyl-2-picrylhydrazyl radical and its product measurement by HPLC. Black-Right-Pointing-Pointer Lowest limit of detection by monitoring 1,1-diphenyl-2-picryl-hydrazine. Black-Right-Pointing-Pointer Adsorption problem of the radical on HPLC parts have been pointed out. - Abstract: 1,1-Diphenyl-2-picrylhydrazyl (DPPH{center_dot}) is a stable nitrogen centred radical widely used to evaluate direct radical scavenging properties of various synthetic or natural antioxidants (AOs). The bleaching rate of DPPH{center_dot} absorbance at 515 nm is usually monitored for this purpose. In order to avoid the interference of complex coloured natural products used as antioxidant supplements or cosmetics, HPLC systems have been reported as alternative techniques to spectrophotometry. They also rely upon measurement of DPPH{center_dot} quenching rate and none of them permits to identify and measure 1,1-diphenyl-2-picryl-hydrazine (DPPH-H), the reduced product of DPPH{center_dot} resulting from hydrogen atom transfer (HAT), which is the main mechanism of the reaction between DPPH{center_dot} and AOs. We presently report an HPLC method devoted to the simultaneous measurement of DPPH{center_dot} and DPPH-H. Both were fully separated on a C18 column eluted with acetonitrile-10 mM ammonium citrate buffer pH 6.8 (70:30, v/v) and detected at 330 nm. Adsorption process of DPPH{center_dot} onto materials of the HPLC system was pointed out. Consequently, the linearity range observed for DPPH{center_dot} was restricted, thus a much lower limit of detection was obtained for DPPH-H than for DPPH{center_dot} using standards (0.02 and 14 {mu}M, respectively). The method was applied to three commonly used AOs, i.e. Trolox{sup Registered-Sign }, ascorbic acid and GSH, and compared with spectrophotometry. Further application to complex matrices (cell culture media, vegetal extracts) and nanomaterials demonstrated (i) its usefulness because of

  17. The activity-integrated method for quality assessment of reduning injection by on-line DPPH-CE-DAD.

    Directory of Open Access Journals (Sweden)

    Yan-xu Chang

    Full Text Available A sensitive on-line DPPH-CE-DAD method was developed and validated for both screening and determining the concentration of seven antioxidants of Reduning injection. The pH and concentrations of buffer solution, SDS, β-CD and organic modifier were studied for the detection of DPPH and seven antioxidants. By on-line mixing DPPH and sample solution, a DPPH-CE method for testing the antioxidant activity of the complex matrix was successfully established and used to screen the antioxidant components of Reduning injection. Then, antioxidant components including caffeic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid were quantified by the newly established CE-DAD method. Finally, the total antioxidant activity and the multiple active components were selected as markers to evaluate the quality of Reduning injection. The results demonstrated that the on-line DPPH-CE-DAD method was reagent-saving, rapid and feasible for on-line simultaneous determination of total pharmacological activity and contents of multi-components samples. It was also a powerful method for evaluating the quality control and mechanism of action of TCM injection.

  18. The influence of genistein on free radicals in normal dermal fibroblasts and keloid fibroblasts examined by EPR spectroscopy.

    Science.gov (United States)

    Jurzak, Magdalena; Ramos, Paweł; Pilawa, Barbara

    2017-01-01

    Normal and keloid fibroblasts were examined using X-band (9.3 GHz) electron paramagnetic resonance spectroscopy. The effect of genistein on the concentration of free radicals in both normal dermal and keloid fibroblasts after ultraviolet irradiation was investigated. The highest concentration of free radicals was seen in keloid fibroblasts, with normal fibroblasts containing a lower concentration. The concentration of free radicals in both normal and keloid fibroblasts was altered in a concentration-dependent manner by the presence of genistein. The change in intra-cellular free radical concentration after the ultraviolet irradiation of both normal and keloid fibroblasts is also discussed. The antioxidant properties of genistein, using its 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity as a model, were tested, and the effect of ultraviolet irradiation on its interaction with free radicals was examined. The electron paramagnetic resonance spectra of DPPH showed quenching by genistein. The interaction of genistein with DPPH free radicals in the absence of ultraviolet irradiation was shown to be slow, but this interaction was much faster under ultraviolet irradiation. Ultraviolet irradiation enhanced the free radical-scavenging activity of genistein.

  19. Radical scavenging activity of lipophilized products from lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids.

    Science.gov (United States)

    Choo, Wee-Sim; Birch, Edward John

    2009-02-01

    Lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate the antioxidant activity of the lipophilized products as model systems for enhanced protection of unsaturated oil. The lipophilized products were identified using ESI-MS. Free radical scavenging activity was determined using the DPPH radical method. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Ferulic acid showed much higher radical scavenging activity than cinnamic acid, which has limited activity. The esterification of cinnamic acid and ferulic acid with triolein resulted in significant increase and decrease in the radical scavenging activity, respectively. These opposite effects were due to the effect of addition of electron-donating alkyl groups on the predominant mechanism of reaction (hydrogen atom transfer or electron transfer) of a species with DPPH. The effect of esterification of cinnamic acid was confirmed using ethyl cinnamate which greatly enhances the radical scavenging activity. Although, compared to the lipophilized cinnamic acid product, the activity was lower. The radical scavenging activity of the main component isolated from lipophilized cinnamic acid product using solid phase extraction, monocinnamoyl dioleoyl glycerol, was as good as the unseparated mixture of lipophilized product. Based on the ratio of a substrate to DPPH concentration, lipophilized ferulic acid was a much more efficient radical scavenger than lipophilized cinnamic acid.

  20. 1,1-Diphenyl-2-picrylhydrazyl radical and superoxide anion scavenging activity of Rhizophora mangle (L.) bark.

    Science.gov (United States)

    Sánchez, Janet Calero; García, Roberto Faure; Cors, Ma Teresa Mitjavila

    2010-09-01

    Rhizophora mangle (L.) produce a variety of substances that possesses pharmacological actions. Although it shown antioxidant properties in some assays, there is no available information about its effect on some free radical species. So the objective of the present research is to evaluate the DPPH radical and superoxide anion scavenging properties of R. mangle extract and its polyphenol fraction. Rhizophora mangle (L.) bark aqueous extract and its major constituent, polyphenols fraction, were investigated for their antioxidant activities employing 2 in vitro assay systems: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals scavenging. IC(50) for DPPH radical-scavenging activity was 6.7 µg tannins/mL for extract and 7.6 µg tannins/mL for polyphenolic fraction. The extract showed better activity than its fraction (P tannins/mL) than the extract (IC(50) = 31.9 µg tannins/mL). Antioxidant activities of both samples increased with the rise of tannins concentration. The comparison of regression lines showed significant differences (P tannin concentrations below the crossing point of both lines, while that fraction was more effective than extract inhibiting the superoxide anions generation. R. mangle aqueous extract showed a potent antioxidant activity, achieved by the scavenging ability observed against DPPH radicals and superoxide anions. Regarding its polyphenolic composition, the antioxidant effects observed in this study are due, most probably, to the presence of polyphenolic compounds.

  1. Structural characterization, α-glucosidase inhibitory and DPPH scavenging activities of polysaccharides from guava.

    Science.gov (United States)

    Zhang, Ziling; Kong, Fansheng; Ni, Hui; Mo, Zhixian; Wan, Jian-Bo; Hua, Dehong; Yan, Chunyan

    2016-06-25

    To explore the chemicals responsible for the health benefits of guava, water-soluble polysaccharides were extracted including GP90 and P90. They exhibited excellent α-glucosidase inhibition activity with an EC50 of 2.27μg/mL and 0.18mg/mL. This suggests that their activities were 1379- and 17-fold higher than the positive control. The DPPH scavenging activities of GP90 was even higher than Vc at some concentrations. Upon further isolation, a novel polysaccharide termed GB90-1B was obtained. Monosaccharide analysis, methylation analysis, and NMR were used to analyze the structural characterization of GB90-1B. Structural analysis revealed that its backbone consisted of (1→5)-linked-α-l-arabinose, (1→2,3,5)-linked-α-l-arabinose and (1→3)-linked-α-l-arabinose. Branch linkages included (1→6)-linked-α-d-glucose, (1→)-linked-α-d-glucose and (1→)-linked-α-l-arabinose. The structure of the repeating unit of GP90-1B was predicted. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Screening of Potential Free Radicals Scavenger and Antibacterial Activities of Purwoceng (Pimpinella alpinaMolk).

    Science.gov (United States)

    Wahyuningrum, Retno; Utami, Pri Iswati; Dhiani, Binar Asrining; Kumalasari, Malikhah; Kusumawardani, Rizka Sari

    2016-11-01

    Purwoceng ( Pimpinella alpina Molk) is a traditional medicinal plant used for its aphrodisiac values. This plant was originated Dieng Plateu, Central Java, Indonesia. Purwoceng has been reported to contain steroid, flavonoids, glycoside, saponins, tannins, and phenolic. Based on secondary metabolite compounds of Purwoceng herbs, a research need to be done to determine the other potential free radicals scavenger and antibacterial activities of Purwoceng. The objectives of this research are to screen the potential free radicals scavenger activity of in vitro using DPPH (1,1 diphenyl-2-picryl-hydrazil) radicals and NO• (nitric oxide) radicals, and antibacterial activity of Purwoceng. The extraction is done by a maceration method with petroleum ether, ethyl acetate, and ethanol solvent, respectively. Free radicals scavenger test was performed using DPPH radicals and NO• radicals, while antibacterial activity screening was performed using agar diffusion test. The results showed that ethyl acetate extract of Purwoceng has free radical scavenger activity with IC50 53.07 ppm lower than butylated hydroxytoluene. Ethyl acetate extract and ethanol extract of Purwoceng have antibacterial activity against Staphyloccus aureus , Escherichia coli , and MG42 bacterial isolate.

  3. Synthesis and Evaluation of the Antioxidant Activity of Lipophilic Phenethyl Trifluoroacetate Esters by In Vitro ABTS, DPPH and in Cell-Culture DCF Assays

    Directory of Open Access Journals (Sweden)

    Roberta Bernini

    2018-01-01

    Full Text Available Polyphenols are natural compounds showing a variety of health-promoting effects. Unfortunately, due to low lipid solubility, their applications in the pharmaceutical, food, and cosmetic industries are limited. With the aim of obtaining novel lipophilic derivatives, the present study reports the synthesis of a series of phenethyl trifluoroacetate esters containing up to two hydroxyl groups in the aromatic ring. Experimental logP values confirmed a greater lipophilicity of the novel compounds compared to the parent compounds. The radical scavenging capacity of all phenethyl trifluoroacetate esters was evaluated by in vitro assays (ABTS, DPPH and in cultured cells (L6 myoblasts and THP-1 leukemic monocytes using 2′,7′-dichlorodihydrofluorescein diacetate. These data revealed that the esters showed a good antioxidant effect that was strictly dependent on the grade of hydroxylation of the phenyl ring. The lack of toxicity, evaluated by the MTT assay and proliferation curves, makes these trifluoroacetates attractive derivatives for pharmaceutical, food, and cosmetic applications.

  4. Effets d'un acide fort sur la réaction de la DPPH avec deux huiles ...

    African Journals Online (AJOL)

    Effets d'un acide fort sur la réaction de la DPPH avec deux huiles essentielles de deux plantes aromatiques acclimatées au Togo. Kokou Agbékonyi Agbodan, Kokouvi Dotse, Kossi Honoré Koumaglo, K. Issa Saloufou ...

  5. Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L., J. oxycedrus (L., J. phoenicea (L. and Tetraclinis articulata (L.

    Directory of Open Access Journals (Sweden)

    Meryem El Jemli

    2016-01-01

    Full Text Available Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC, and ferric reducing antioxidant power (FRAP assays. Also the total phenolic and flavonoids contents of the extracts were determined spectrophotometrically. Results. All the extracts showed interesting antioxidant activities compared to the standard antioxidants (butylated hydroxytoluene (BHT, quercetin, and Trolox. The aqueous extract of Juniperus oxycedrus showed the highest antioxidant activity as measured by DPPH, TEAC, and FRAP assays with IC50 values of 17.91±0.37 μg/mL, 19.80±0.55 μg/mL, and 24.23±0.07 μg/mL, respectively. The strong correlation observed between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor to antioxidant properties of these plants extracts. Conclusion. These results suggest that the aqueous extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus phoenicea, and Tetraclinis articulata can constitute a promising new source of natural compounds with antioxidants ability.

  6. Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L.), J. oxycedrus (L.), J. phoenicea (L.) and Tetraclinis articulata (L.).

    Science.gov (United States)

    El Jemli, Meryem; Kamal, Rabie; Marmouzi, Ilias; Zerrouki, Asmae; Cherrah, Yahia; Alaoui, Katim

    2016-01-01

    Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic and flavonoids contents of the extracts were determined spectrophotometrically. Results. All the extracts showed interesting antioxidant activities compared to the standard antioxidants (butylated hydroxytoluene (BHT), quercetin, and Trolox). The aqueous extract of Juniperus oxycedrus showed the highest antioxidant activity as measured by DPPH, TEAC, and FRAP assays with IC50 values of 17.91 ± 0.37 μg/mL, 19.80 ± 0.55 μg/mL, and 24.23 ± 0.07 μg/mL, respectively. The strong correlation observed between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor to antioxidant properties of these plants extracts. Conclusion. These results suggest that the aqueous extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus phoenicea, and Tetraclinis articulata can constitute a promising new source of natural compounds with antioxidants ability.

  7. A radical approach to radical innovation

    NARCIS (Netherlands)

    D. Deichmann (Dirk); J.C.M. van den Ende (Jan)

    2014-01-01

    textabstractInnovation pays. Amazon, Apple, Facebook, Google – nearly every one of today’s most successful companies has a talent for developing radical new ideas. But how best to encourage radical initiative taking from employees, and does their previous success or failure at it play a role?

  8. Interactions of short-acting, intermediate-acting and pre-mixed human insulins with free radicals--Comparative EPR examination.

    Science.gov (United States)

    Olczyk, Paweł; Komosinska-Vassev, Katarzyna; Ramos, Paweł; Mencner, Łukasz; Olczyk, Krystyna; Pilawa, Barbara

    2015-07-25

    Electron paramagnetic resonance (EPR) spectroscopy was used to examine insulins interactions with free radicals. Human recombinant DNA insulins of three groups were studied: short-acting insulin (Insuman Rapid); intermediate-acting insulins (Humulin N, Insuman Basal), and pre-mixed insulins (Humulin M3, Gensulin M50, Gensulin M40, Gensulin M30). The aim of an X-band (9.3GHz) study was comparative analysis of antioxidative properties of the three groups of human insulins. DPPH was used as a stable free radical model. Amplitudes of EPR lines of DPPH as the paramagnetic free radical reference, and DPPH interacting with the individual tested insulins were compared. For all the examined insulins kinetics of their interactions with free radicals up to 60 min were obtained. The strongest interactions with free radicals were observed for the short-acting insulin - Insuman Rapid. The lowest interactions with free radicals were characteristic for intermediate-acting insulin - Insuman Basal. The pre-mixed insulins i.e. Humulin M3 and Gensulin M50 revealed the fastest interactions with free radicals. The short acting, intermediate acting and premixed insulins have been found to be effective agents in reducing free radical formation in vitro and should be further considered as potential useful tools in attenuation of oxidative stress in diabetic patients. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Applicability of the DPPH assay for evaluating the antioxidant capacity of food additives - inter-laboratory evaluation study -.

    Science.gov (United States)

    Shimamura, Tomoko; Sumikura, Yoshihiro; Yamazaki, Takeshi; Tada, Atsuko; Kashiwagi, Takehiro; Ishikawa, Hiroya; Matsui, Toshiro; Sugimoto, Naoki; Akiyama, Hiroshi; Ukeda, Hiroyuki

    2014-01-01

    An inter-laboratory evaluation study was conducted in order to evaluate the antioxidant capacity of food additives by using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Four antioxidants used as existing food additives (i.e., tea extract, grape seed extract, enju extract, and d-α-tocopherol) and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) were used as analytical samples, and 14 laboratories participated in this study. The repeatability relative standard deviation (RSD(r)) of the IC50 of Trolox, four antioxidants, and the Trolox equivalent antioxidant capacity (TEAC) were 1.8-2.2%, 2.2-2.9%, and 2.1-2.5%, respectively. Thus, the proposed DPPH assay showed good performance within the same laboratory. The reproducibility relative standard deviation (RSD(R)) of IC50 of Trolox, four antioxidants, and TEAC were 4.0-7.9%, 6.0-11%, and 3.7-9.3%, respectively. The RSD(R)/RSD(r) values of TEAC were lower than, or nearly equal to, those of IC50 of the four antioxidants, suggesting that the use of TEAC was effective for reducing the variance among the laboratories. These results showed that the proposed DPPH assay could be used as a standard method to evaluate the antioxidant capacity of food additives.

  10. Contemporary Radical Economics.

    Science.gov (United States)

    Sherman, Howard J.

    1984-01-01

    The origins of contemporary radical economics are examined. Applications of radical economics to price and value theory, labor segmentation theory, business cycles, industrial organization, government and business, imperialism and development, and comparative systems are reviewed. (Author/RM)

  11. Stable radical content and anti-radical activity of roasted Arabica coffee: from in-tact bean to coffee brew.

    Directory of Open Access Journals (Sweden)

    Gordon J Troup

    Full Text Available The roasting of coffee beans generates stable radicals within melanoidins produced by non-enzymatic browning. Roasting coffee beans has further been suggested to increase the antioxidant (AO capacity of coffee brews. Herein, we have characterized the radical content and AO capacity of brews prepared from Coffea arabica beans sourced directly from an industrial roasting plant. In-tact beans exhibited electron paramagnetic resonance signals arising from Fe3+, Mn2+ and at least three distinct stable radicals as a function of roasting time, whose intensity changed upon grinding and ageing. In coffee brews, the roasting-induced radicals were harboured within the high molecular weight (> 3 kD melanoidin-containing fraction at a concentration of 15 nM and was associated with aromatic groups within the melanoidins. The low molecular weight (< 3 kD fraction exhibited the highest AO capacity using DPPH as an oxidant. The AO activity was not mediated by the stable radicals or by metal complexes within the brew. While other non-AO functions of the roasting-induced radical and metal complexes may be possible in vivo, we confirm that the in vitro antiradical activity of brewed coffee is dominated by low molecular weight phenolic compounds.

  12. A strategy for high-speed countercurrent chromatography purification of specific antioxidants from natural products based on on-line HPLC method with radical scavenging assay.

    Science.gov (United States)

    Inoue, Koichi; Baba, Erika; Hino, Tomoaki; Oka, Hisao

    2012-10-15

    We have proposed a novel and first strategy of high-speed countercurrent chromatography (HSCCC) purification for the efficient and effective discovery of antioxidant from natural product based on on-line HPLC method with radical scavenging assay. To achieve a strategy for HSCCC purification, the antioxidants in materials are identified by on-line HPLC with DPPH radical scavenging assay. Then, the optimal condition of target peaks would be investigated for the two-phase solvent system, and purified by HSCCC. In this study, the specific antioxidants in red cabbage, perilla and elderberry pigments were evaluated by on-line HPLC with DPPH radical scavenging assay, and purified by HSCCC technique. Specific antioxidants could be rapidly pinpointed in complex mixtures by on-line HPLC with DPPH radical scavenging assay. Then, the optimal two-phase solvent systems were investigated using these HPLC peaks. Finally, the purification of these nine antioxidants form three mixtures were performed by HSCCC. Using mass spectrometric analysis, these antioxidants were confirmed to cyanidin-based anthocyanin from red cabbage and elderberry pigments, and luteolin-based flavones from perrilla pigment. Due to the advantages derived from on-line HPLC with DPPH radical scavenging assay and HSCCC technique, a rapid, efficient and effective strategy has been developed for the discovery of antioxidants from natural products. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Strong antiferromagnetic coupling of spins in the (MDABCO+)(C60·-) salt with 3D close packing of the C60·- radical anions (MDABCO+: N-methyldiazabicyclooctanium cation).

    Science.gov (United States)

    Konarev, Dmitri V; Khasanov, Salavat S; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2014-06-01

    A new salt, (MDABCO(+))(C60(·-)) (1; MDABCO(+) = N-methyldiazabicyclooctanium cation), was obtained as single crystals. The crystal structure of 1 determined at 250 and 100 K showed 3D close packing of fullerenes with eight fullerene neighbors for each C60(·-). These neighbors are located at 10.01-10.11 Å center-to-center distances (250 K) and van der Waals interfullerene C⋅⋅⋅C contacts are formed with four fullerene neighbors arranged in the bc plane. Fullerene ordering observed below 160 K is accompanied by the appearance of one and a half independent C60(·-) and trebling of the unit cell along the b axis. Fullerenes are packed closer to each other at 100 K. As a result, fullerenes are located in the three-dimensional packing at 9.91-10.12 Å center-to-center distances and 18 short interfullerene C⋅⋅⋅C contacts are formed for each C60(·-). Although they are closed packed, fullerenes are not dimerized down to 1.9 K. Magnetic data indicate strong antiferromagnetic coupling of spins in the 70-300 K range with a Weiss temperature of Θ = -118 K. Magnetic susceptibility shows a round maximum at 46 K. Such behavior can be described well by the Heisenberg model for square two-dimensional antiferromagnetic coupling of spins with an exchange interaction of J/kB = -25.3 K. This magnetic coupling is one of the strongest observed for C60(·-) salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Ultrasound-assisted biosynthesis of CuO-NPs using brown alga Cystoseira trinodis: Characterization, photocatalytic AOP, DPPH scavenging and antibacterial investigations.

    Science.gov (United States)

    Gu, Haidong; Chen, Xiao; Chen, Feng; Zhou, Xing; Parsaee, Zohreh

    2018-03-01

    This contribution reports the biosynthesis of CuO NPs via ultrasound method using the Cystoseira trinodis extracts as an eco friendly and time saving process. The characterization of cupric oxide NPs was performed using XRD, FE-SEM, EDX, TEM, AFM, photoluminescence, UV-Vis, Raman and FT-IR spectroscopy investigations. SEM images show the spherical structure with the average crystallite size 6nm to 7.8nm of CuO. XRD analysis approved the formation of pure monoclinic crystallite structures of CuO NPs. These observations were confirmed by TEM analysis. The photocatalytic studies reveal the activity of the prepared CuO NPs as an efficient catalyst for the degradation of methylene blue (MB) in the presence of UV and Sunlight. CuO NPs under varying experimental parameters such as dye concentration, catalytic load, pH. The results of the in vitro biological screening effect of CuO NPs (zone of growth inhibition and minimal inhibitory concentrations) in comparison with cephalexin (as a standard compound) using the disc diffusion method was demonstrated the significant bactericidal activity against some bacteria strain including Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), and Streptococcus faecalis (S. faecalis). Furthermore, the Nps found to inhibit the activity of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals effectively. This study introduces a facile, green and low coast method for the synthesis of monoclinic CuO NPs with catalytic, antioxidant and antibacterial properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Radical theory of rings

    CERN Document Server

    Gardner, JW

    2003-01-01

    Radical Theory of Rings distills the most noteworthy present-day theoretical topics, gives a unified account of the classical structure theorems for rings, and deepens understanding of key aspects of ring theory via ring and radical constructions. Assimilating radical theory's evolution in the decades since the last major work on rings and radicals was published, the authors deal with some distinctive features of the radical theory of nonassociative rings, associative rings with involution, and near-rings. Written in clear algebraic terms by globally acknowledged authorities, the presentation

  16. Simultaneous quantification of ten constituents of Xanthoceras sorbifolia Bunge using UHPLC-MS methods and evaluation of their radical scavenging, DNA scission protective, and α-glucosidase inhibitory activities.

    Science.gov (United States)

    Zhang, Yu; Ma, Jian-Nan; Ma, Chun-Li; Qi, Zhi; Ma, Chao-Mei

    2015-11-01

    The present study was designed to investigate the bioactive constituents of Xanthoceras sorbifolia in terms of amounts and their antioxidant, DNA scission protection, and α-glucosidase inhibitory activities. Simultaneous quantification of 10 X. sorbifolia constituents was carried out by a newly established ultra-high performance liquid chromatography-quadrupole mass spectrometry method (UHPLC-MS). The antioxidant activities were evaluated by measuring DPPH radical scavenging and DNA scission protective activities. The α-glucosidase inhibitory activities were investigated by using an assay with α-glucosidase from Bacillus Stearothermophilus and disaccharidases from mouse intestine. We found that the wood of X. sorbifolia was rich in phenolic compounds with the contents of catechin, epicatechin, myricetin, and dihydromyricetin being 0.12-0.19, 1.94-2.16, 0.77-0.91, and 6.76-7.89 mg·g(-1), respectively. The four constituents strongly scavenged DPPH radicals (with EC50 being 4.2, 3.8 and 5.7 μg·mL(-1), respectively) and remarkably protected peroxyl radical-induced DNA strand scission (92.10%, 94.66%, 75.44% and 89.95% of protection, respectively, at a concentration of 10 μmol·L(-1)). A dimeric flavan 3-ol, epigallocatechin-(4β→8, 2β→O-7)-epicatechin potently inhibited α-glucosidase with an IC50 value being as low as 1.2 μg·mL(-1). The established UHPLC-MS method could serve as a quality control tool for X. sorbifolia. In conclusion, the high contents of antioxidant and α-glucosidase inhibitory constituents in X. sorbifolia support its use as complementation of other therapeutic agents for metabolic disorders, such as diabetes and hypertension. Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  17. Examining food additives and spices for their anti-oxidant ability to counteract oxidative damage due to chronic exposure to free radicals from environmental pollutants

    Science.gov (United States)

    Martinez, Raul A., III

    The main objective of this work was to examine food additives and spices (from the Apiaceae family) to determine their antioxidant properties to counteract oxidative stress (damage) caused by Environmental pollutants. Environmental pollutants generate Reactive Oxygen species and Reactive Nitrogen species. Star anise essential oil showed lower antioxidant activity than extracts using DPPH scavenging. Dill Seed -- Anethum Graveolens -the monoterpene components of dill showed to activate the enzyme glutathione-S-transferase , which helped attach the antioxidant molecule glutathione to oxidized molecules that would otherwise do damage in the body. The antioxidant activity of extracts of dill was comparable with ascorbic acid, alpha-tocopherol, and quercetin in in-vitro systems. Black Cumin -- Nigella Sativa: was evaluated the method 1,1-diphenyl2-picrylhhydrazyl (DPPH) radical scavenging activity. Positive correlations were found between the total phenolic content in the black cumin extracts and their antioxidant activities. Caraway -- Carum Carvi: The antioxidant activity was evaluated by the scavenging effects of 1,1'-diphenyl-2-picrylhydrazyl (DPPH). Caraway showed strong antioxidant activity. Cumin -- Cuminum Cyminum - the major polyphenolic were extracted and separated by HPTLC. The antioxidant activity of the cumin extract was tested on 1,1'-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging. Coriander -- Coriandrum Sativum - the antioxidant and free-radical-scavenging property of the seeds was studied and also investigated whether the administration of seeds curtails oxidative stress. Coriander seed powder not only inhibited the process of Peroxidative damage, but also significantly reactivated the antioxidant enzymes and antioxidant levels. The seeds also showed scavenging activity against superoxides and hydroxyl radicals. The total polyphenolic content of the seeds was found to be 12.2 galic acid equivalents (GAE)/g while the total flavonoid content

  18. [Lavoisier and radicals].

    Science.gov (United States)

    Lafont, Olivier

    2007-01-01

    Lavoisier and his co-workers (Guyton de Morveau, Bertholet, Fourcroy) considered that acids were constituted of oxygen and of something else that they called radicals. These radicals were known in some cases, i.e. nitrogen for nitrous acid, carbon for carbonic acid, phosphorus for phosphoric acid. In the case of sulfur, the sulfuric radical could be associated with different quantities of oxigen leading to sulfuric or sulfurous acids. In other cases radicals remained unknown at the time i.e. muriatic radical for muriatic acid, or benzoyl radical for benzoic acid. It is interesting to notice that Lavoisier evoked the case of compound radicals constituted of different substances such as carbon and hydrogen.

  19. Development of an HPLC post-column antioxidant assay for Solidago canadensis radical scavengers.

    Science.gov (United States)

    Marksa, Mindaugas; Radušienė, Jolita; Jakštas, Valdas; Ivanauskas, Liudas; Marksienė, Rūta

    2016-01-01

    The aim of this work was to modify and validate the post-column high-performance liquid chromatography (HPLC)-ABTS and DPPH methods for evaluating the antioxidant activity of the methanolic extracts of Solidago canadensis (Canadian goldenrod) leaves and flowers. Separation of the analytes was performed via the HPLC-PDA method on a YMC analytical column using a gradient elution program. Three compounds with antioxidant properties - chlorogenic acid, rutin and isoquercitrin - and two unidentified antioxidants were established. The research showed that the coil temperature regimes and loop length combinations influence the optimised post-column assay method for detecting the antioxidant activity of goldenrod radical scavengers. Investigations established that the temperature in the reaction coil was a substantial factor contributing to the signal strength of the analytes after reacting with the DPPH and ABTS radicals.

  20. Evaluation of the free radical scavenging activity and radioprotective efficacy of Grewia asiatica fruit

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Krishna V; Sisodia, Rashmi [Radiation Biology Laboratory, Department of Zoology, University of Rajasthan, Jaipur, Rajasthan-302055 (India)], E-mail: rashsisodia@yahoo.co.in

    2009-09-01

    The radioprotective effect of Grewia asiatica fruit (GAE) which contains anthocyanin-type cyanidin 3-glucoside, vitamins C and A, minerals, carotenes and dietary fibre was studied. For the study Swiss albino mice were divided into five groups: (1) control (vehicle treated); (2) GAE treated (700 mg kg{sup -1} day{sup -1} for 15 days); (3) irradiated (5 Gy); (4) GAE+irradiated and (5) irradiated+GAE treated. The irradiation of animals resulted in a significant elevation of lipid peroxidation in terms of thiobarbituric acid reactive substances (TBARS) content and depletion in glutathione (GSH) and protein levels at all intervals studied, namely 1-30 days, in comparison to the control group. Treatment of mice with GAE before and after irradiation caused a significant depletion in TBARS content followed by a significant elevation in GSH and protein concentration in the intestine and testis of mice at all post-irradiation autopsy intervals in comparison to irradiated mice. Significant protection of DNA and RNA in testis was also noticed. GAE was found to have strong radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH{sup *}) and O{sub 2}{sup -} assays and also showed in vitro radioprotective activity in protein carbonyl assay in a dose-dependent manner. The above results prove the radioprotective efficacy of GAE.

  1. Contemporary Radical Prostatectomy

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2011-01-01

    Full Text Available Purpose. Patients diagnosed with clinically localized prostate cancer have more surgical treatment options than in the past. This paper focuses on the procedures' oncological or functional outcomes and perioperative morbidities of radical retropubic prostatectomy, radical perineal prostatectomy, and robotic-assisted laparoscopic radical prostatectomy. Materials and Methods. A MEDLINE/PubMed search of the literature on radical prostatectomy and other new management options was performed. Results. Compared to the open procedures, robotic-assisted radical prostatectomy has no confirmed significant difference in most literatures besides less blood loss and blood transfusion. Nerve sparing is a safe means of preserving potency on well-selected patients undergoing radical prostatectomy. Positive surgical margin rates of radical prostatectomy affect the recurrence and survival of prostate cancer. The urinary and sexual function outcomes have been vastly improved. Neoadjuvant treatment only affects the rate of positive surgical margin. Adjuvant therapy can delay and reduce the risk of recurrence and improve the survival of the high risk prostate cancer. Conclusions. For the majority of patients with organ-confined prostate cancer, radical prostatectomy remains a most effective approach. Radical perineal prostatectomy remains a viable approach for patients with morbid obesity, prior pelvic surgery, or prior pelvic radiation. Robot-assisted laparoscopic prostatectomy (RALP has become popular among surgeons but has not yet become the firmly established standard of care. Long-term data have confirmed the efficacy of radical retropubic prostatectomy with disease control rates and cancer-specific survival rates.

  2. Free radical scavenging activity and lipid peroxidation inhibition of Hypericum helianthemoides (spach Boiss

    Directory of Open Access Journals (Sweden)

    Soheila Moein

    2015-06-01

    Full Text Available Antioxidants are compounds that obstruct the oxidation of macromolecules in the body. In general, there are two categories of antioxidants, natural and synthetic. Recently, interest has been increased considerably for obtaining new natural antioxidants. In this study, the scavenging of free radicals such as DPPH, NO and OH by Hypericum helianthemoides extract was evaluated. Also, the antioxidant properties of this extract were evaluated by FRAP, FTC methods and determination phenolic compounds. The plant was collected from north of Fars Province and plant extraction was obtained using ethanol. In DPPH radical scavenging, different concentrations of the Hypericum extract were added to DPPH radical. In hydroxyl radical scavenging, Fenton reaction mixture, TCA and TBA were mixed with Hypericum extract. In nitric radical scavenging, nitropruside was mixed with Hypericum extract and then sulphanilic acid, naphthylene diamine were added. In determination of phenolic compounds, Folin-ciocalteu and sodium carbonate were added to Hypericum extract. In DPPH radical scavenging, the IC50 of Hypericum extract (309.35±6.5μg/ml was higher than the antioxidant standards, BHT (IC50=81.9±2.6 μg/ml and quercetin (IC50=60.04±6.48 μg/ml. The highest scavenging of hydroxyl radicals was observed in Hypericum extract (70.3±0.8%, 125 μg/ml. In gallic acid it was (73.8±3.3%. In 200 μg/ml of Hypericum extract scavenged NO radical (85.2±2.7%. In FRAP method, the IC50 of this extract was 109.7±10.5 μg/ml. In FTC method, the inhibition of lipid peroxidation by Hypericum extract, BHT and ascorbic acid were 59.2±2.2, 66.9±0.15, 64.06±0.02 respectively. Total phenol of the plant extract was 3±0.4 mg/g.

  3. Antioxidant markers based TLC-DPPH differentiation on four commercialized botanical sources of Shankhpushpi (A Medhya Rasayana): A preliminary assessment.

    Science.gov (United States)

    Sethiya, Neeraj K; Raja, M K Mohan Maruga; Mishra, Shri Hari

    2013-01-01

    Shankhpushpi is a cognition boosting traditional ayurvedic brain supplement. Convolvulus pluricaulis (Convolvulaceae), Evolvulus alsinoides (Convolvulaceae), Clitoria ternatea (Papilionaceae), and Canscora decussata (Gentianaceae) are botanical claimants of Shankhpushpi. This investigation is to focus the identification of the compound based on biological marker differentiation of four botanical claimants of Shankhpushpi for their antioxidant evaluation on thin layer chromatography (TLC) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. A rapid TLC-DPPH method was developed to identify and differentiate four botanical claimants of Shankhpushpi in terms of presence of β-carotene, rutin, scopoletin, chlorogenic acid, and mangiferin. C. pluricaulis shows presence of scopoletin; E. alsinoides shows presence of β-carotene, scopoletin, and chlorogenic acid; C. ternatea shows presence of β-carotene, scopoletin, and rutin; and C. decussata shows presence of β-carotene, scopoletin, and mangiferin. The order, they followed, based on their antioxidant potential is β-carotene < mangiferin < rutin < scopoletin < chlorogenic acid. Antioxidants are attributed for their beneficial role in age-related cognition decline. The proposed method provides an edge in terms of identification and quantification of antioxidant constituents in a multi-component system. This method may also provide application for identification of correct plant sources used in the name of Shankhpushpi in marketed ayurvedic formulation, food supplement, and extracts.

  4. Antioxidant markers based TLC-DPPH differentiation on four commercialized botanical sources of Shankhpushpi (A Medhya Rasayana: A preliminary assessment

    Directory of Open Access Journals (Sweden)

    Neeraj K Sethiya

    2013-01-01

    Full Text Available Shankhpushpi is a cognition boosting traditional ayurvedic brain supplement. Convolvulus pluricaulis (Convolvulaceae, Evolvulus alsinoides (Convolvulaceae, Clitoria ternatea (Papilionaceae, and Canscora decussata (Gentianaceae are botanical claimants of Shankhpushpi. This investigation is to focus the identification of the compound based on biological marker differentiation of four botanical claimants of Shankhpushpi for their antioxidant evaluation on thin layer chromatography (TLC by 2,2-diphenyl-1-picrylhydrazyl (DPPH method. A rapid TLC-DPPH method was developed to identify and differentiate four botanical claimants of Shankhpushpi in terms of presence of β-carotene, rutin, scopoletin, chlorogenic acid, and mangiferin. C. pluricaulis shows presence of scopoletin; E. alsinoides shows presence of β-carotene, scopoletin, and chlorogenic acid; C. ternatea shows presence of β-carotene, scopoletin, and rutin; and C. decussata shows presence of β-carotene, scopoletin, and mangiferin. The order, they followed, based on their antioxidant potential is β-carotene < mangiferin < rutin < scopoletin < chlorogenic acid. Antioxidants are attributed for their beneficial role in age-related cognition decline. The proposed method provides an edge in terms of identification and quantification of antioxidant constituents in a multi-component system. This method may also provide application for identification of correct plant sources used in the name of Shankhpushpi in marketed ayurvedic formulation, food supplement, and extracts.

  5. Investigation of the effect of chamazulene on lipid peroxidation and free radical processes.

    Science.gov (United States)

    Rekka, E A; Kourounakis, A P; Kourounakis, P N

    1996-06-01

    Oxygen toxicity and related free radical reactions are implicated in numerous pathophysiological conditions, like atherosclerosis, inflammation, gastric ulceration, neuronal degeneration, tumour promotion. The flowers of Matricaria chamomilla, Asteraceae, have been used therapeutically for conditions in which oxidative stress is supposed to be implicated. We considered interesting to investigate the effect of Chamazulene, the active substance of chamomile, on free radical processes. Membrane lipid peroxidation was induced by Fe2+/ascorbate and assessed as the 2-thiobarbituric acid reactive material. The hydroxyl radical scavenging activity was studied as the competition of Chamazulene with DMSO for HO. generated by Fe3+/ascorbate. Finally, the interaction of Chamazulene with the N-centered stable free radical DPPH was estimated photometrically (517 nm). It was found that Chamazulene inhibited lipid peroxidation in a concentration and time dependent manner presenting an IC50 of 18 microM after 45 min incubation. It could also inhibit the autoxidation of DMSO (33 mM) by 76% at 25 mM, and had a weak capacity to interact with DPPH. In conclusion, Chamazulene presents interesting properties concerning radical processes.

  6. Orgasm after radical prostatectomy

    NARCIS (Netherlands)

    Koeman, M; VanDriel, MF; Schultz, WCMW; Mensink, HJA

    Objective To evaluate the ability to obtain and the quality of orgasm after radical prostatectomy, Patients and methods The orgasms experienced after undergoing radical prostatectomy were evaluated in 20 men (median age 65 years, range 56-76) using a semi-structured interview and a self-administered

  7. Muonium and muonic radicals

    International Nuclear Information System (INIS)

    Burkhard, P.; Fischer, H.; Roduner, E.; Strub, W.; Geeson, D.; Symons, M.C.R.

    1985-01-01

    An energetic positive muon which is injected in a liquid sample of substrate molecules (S) creates an ionization track consisting of substrate cations (S + ) and electrons. Near the end of this track the muon may combine with an electron to form muonium (Mu) which is observable in inert liquids, but which reacts by addition to form a radical. Alternatively, the electron can add to S to form S - , which then combines with the muon to form the radical. Furthermore, instead of ending up in Mu or in a radical the muon may stay in a diamagnetic environment as a solvated muon, or as a muon substituting a proton in a molecule. Of interest in these schemes are the mechanisms and rates of formation of muonated radicals and in particular the rate constants for their reactions to products. Investigations are based on the observation of Mu and the radical by means of the μSR technique in transverse magnetic fields. (Auth.)

  8. Monocyte-macrophage membrane possesses free radicals scavenging activity: stimulation by polyphenols or by paraoxonase 1 (PON1).

    Science.gov (United States)

    Rosenblat, M; Elias, A; Volkova, N; Aviram, M

    2013-04-01

    In the current study, we analysed free radicals scavenging activity of monocytes-macrophages in the absence or presence of antioxidants such as polyphenols or paraoxonase 1 (PON1). THP-1 human monocytic cell line, murine J774A.1 macrophages, as well as human primary monocytes have the capability to scavenge free radicals, as measured by the 1-diphenyl-2-picryl-hydrazyl (DPPH) assay. This effect (which could be attributed to the cell's membrane) was cell number and incubation time dependent. Upon incubation of J774A.1 macrophages with acetylated LDL (Ac-LDL), with VLDL, or with the radical generator, AAPH, the cells' lipid peroxides content, and paraoxonase 2 (PON2) activity were significantly increased. While non-treated cells decreased DPPH absorbance by 65%, the Ac-LDL-, VLDL- or AAPH-treated cells, decreased it by only 33%, 30%, or 45%, respectively. We next analysed the effect of J774A.1 macrophage enrichment with antioxidants, such as polyphenols or PON1 on the cells' free radicals scavenging activity. Non-treated cells decreased DPPH absorbance by 50%, whereas vitamin E-, punicalagin- or PJ-treated cells significantly further decreased it, by 75%. Similarly, in PON1-treated cells DPPH absorbance was further decreased by 63%, in association with 23% increment in PON1 catalytic activity. In cells under oxidative stress [treated with AAPH-, or with oxidized LDL], PON1 activity was decreased by 31% or 40%, as compared to the activity observed in PON1 incubated with non-treated cells. We conclude that monocytes-macrophages possess free radicals scavenging activity, which is decreased under atherogenic conditions, and increased upon cell enrichment with potent antioxidants such as nutritional polyphenols, or PON1.

  9. Covalently Bound Nitroxyl Radicals in an Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Barbara K.; Braunecker, Wade A.; Bobela, David C.; Nanayakkara, Sanjini U.; Reid, Obadiah G.; Johnson, Justin C.

    2016-09-15

    A series of covalent organic framework (COF) structures is synthesized that possesses a tunable density of covalently bound nitroxyl radicals within the COF pores. The highest density of organic radicals produces an electron paramagnetic resonance (EPR) signal that suggests the majority of radicals strongly interact with other radicals, whereas for smaller loadings the EPR signals indicate the radicals are primarily isolated but with restricted motion. The dielectric loss as determined from microwave absorption of the framework structures compared with an amorphous control suggests that free motion of the radicals is inhibited when more than 25% of available sites are occupied. The ability to tune the mode of radical interactions and the subsequent effect on redox, electrical, and optical characteristics in a porous framework may lead to a class of structures with properties ideal for photoelectrochemistry or energy storage.

  10. Carbohydrase inhibition and anti-cancerous and free radical scavenging properties along with DNA and protein protection ability of methanolic root extracts of Rumex crispus.

    Science.gov (United States)

    Shiwani, Supriya; Singh, Naresh Kumar; Wang, Myeong Hyeon

    2012-10-01

    The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for 60℃ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content (211 µg/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC(50) = 42.86 (absolute methanol) and 36.91 µg/mL (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in H(2)O(2)/Fe(3+)/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at 400 µg/mL was observed to be highest (10.2% ± 1.03). Moreover, methanolic RERC inhibited α-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.

  11. Environmentally persistent free radicals (EPFRs)-2. Are free hydroxyl radicals generated in aqueous solutions?

    Science.gov (United States)

    Khachatryan, Lavrent; Dellinger, Barry

    2011-11-01

    A chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed to measure the production of hydroxyl radical (·OH) in aqueous suspensions of 5% Cu(II)O/silica (3.9% Cu) particles containing environmentally persistent free radicals (EPFRs) of 2-monochlorophenol (2-MCP). The results indicate: (1) a significant differences in accumulated DMPO-OH adducts between EPFR containing particles and non-EPFR control samples, (2) a strong correlation between the concentration of DMPO-OH adducts and EPFRs per gram of particles, and (3) a slow, constant growth of DMPO-OH concentration over a period of days in solution containing 50 μg/mL EPFRs particles + DMPO (150 mM) + reagent balanced by 200 μL phosphate buffered (pH = 7.4) saline. However, failure to form secondary radicals using standard scavengers, such as ethanol, dimethylsulfoxide, sodium formate, and sodium azide, suggests free hydroxyl radicals may not have been generated in solution. This suggests surface-bound, rather than free, hydroxyl radicals were generated by a surface catalyzed-redox cycle involving both the EPFRs and Cu(II)O. Toxicological studies clearly indicate these bound free radicals promote various types of cardiovascular and pulmonary disease normally attributed to unbound free radicals; however, the exact chemical mechanism deserves further study in light of the implication of formation of bound, rather than free, hydroxyl radicals.

  12. DFT and ENDOR Study of Bixin Radical Cations and Neutral Radicals on Silica-Alumina.

    Science.gov (United States)

    Tay-Agbozo, Sefadzi S; Krzyaniak, Matthew D; Bowman, Michael K; Street, Shane; Kispert, Lowell D

    2015-06-18

    Bixin, a carotenoid found in annatto (Bixa orellana), is unique among natural carotenoids by being water-soluble. We stabilized free radicals from bixin on the surface of silica-alumina (Si-Al) and characterized them by pulsed electron-nuclear double resonance (ENDOR). DFT calculations of unpaired electron spin distribution for various bixin radicals predict the EPR hyperfine couplings. Least-square fitting of experimental ENDOR spectra by spectra calculated from DFT hyperfine couplings characterized the radicals trapped on Si-Al. DFT predicts that the trans bixin radical cation is more stable than the cis bixin radical cation by 1.26 kcal/mol. This small energy difference is consistent with the 26% trans and 23% cis radical cations in the ENDOR spectrum. The remainder of the ENDOR spectrum is due to several neutral radicals formed by loss of a H(+) ion from the 9, 9', 13, or 13' methyl group, a common occurrence in all water-insoluble carotenoids previously studied. Although carboxyl groups of bixin strongly affect its solubility relative to other natural carotenoids, they do not alter properties of its free radicals based on DFT calculations and EPR measurements which remain similar to typical water-insoluble carotenoids.

  13. Synthesis of Benzofuran-2-One Derivatives and Evaluation of Their Antioxidant Capacity by Comparing DPPH Assay and Cyclic Voltammetry

    Directory of Open Access Journals (Sweden)

    Martina Miceli

    2018-03-01

    Full Text Available The present work aimed to synthesise promising antioxidant compounds as a valuable alternative to the currently expensive and easily degradable molecules that are employed as stabilizers in industrial preparation. Taking into account our experience concerning domino Friedel-Crafts/lactonization reactions, we successfully improved and extended the previously reported methodology toward the synthesis of 3,3-disubstituted-3H-benzofuran-2-one derivatives 9–20 starting from polyphenols 1–6 as substrates and either diethylketomalonate (7 or 3,3,3-trifluoromethyl pyruvate (8 as electrophilic counterpart. The antioxidant capacity of the most stable compounds (9–11 and 15–20 was evaluated by both DPPH assay and Cyclic Voltammetry analyses performed in alcoholic media (methanol as well as in aprotic solvent (acetonitrile. By comparing the recorded experimental data, a remarkable activity can be attributed to few of the tested lactones.

  14. Salvage robotic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Samuel D Kaffenberger

    2014-01-01

    Full Text Available Failure of non-surgical primary treatment for localized prostate cancer is a common occurrence, with rates of disease recurrence ranging from 20% to 60%. In a large proportion of patients, disease recurrence is clinically localized and therefore potentially curable. Unfortunately, due to the complex and potentially morbid nature of salvage treatment, radical salvage surgery is uncommonly performed. In an attempt to decrease the morbidity of salvage therapy without sacrificing oncologic efficacy, a number of experienced centers have utilized robotic assistance to perform minimally invasive salvage radical prostatectomy. Herein, we critically evaluate the existing literature on salvage robotic radical prostatectomy with a focus on patient selection, perioperative complications and functional and early oncologic outcomes. These results are compared with contemporary and historical open salvage radical prostatectomy series and supplemented with insights we have gained from our experience with salvage robotic radical prostatectomy. The body of evidence by which conclusions regarding the efficacy and safety of robotic salvage radical prostatectomy can be drawn comprises fewer than 200 patients with limited follow-up. Preliminary results are promising and some outcomes have been favorable when compared with contemporary open salvage prostatectomy series. Advantages of the robotic platform in the performance of salvage radical prostatectomy include decreased blood loss, short length of stay and improved visualization. Greater experience is required to confirm the long-term oncologic efficacy and functional outcomes as well as the generalizability of results achieved at experienced centers.

  15. Radical's view of sciences

    International Nuclear Information System (INIS)

    Mittal, J.P.

    2004-01-01

    Full text: General concept in radiation biology is that free radicals are highly reactive and they can damage vital cellular molecules leading to injurious effects. However, in this talk, evidence will be presented through the techniques of electron paramagnetic resonance ( EPR ) and pulse radiolysis that free radicals can be highly selective in their reaction with the target molecules. In addition, attempts will be made to present a brief account of emerging scenario of free radical generation, identification and their involvement in radiation damage mechanisms in chemical and biological systems

  16. An Efficient Method for the Preparative Isolation and Purification of Flavonoid Glycosides and Caffeoylquinic Acid Derivatives from Leaves of Lonicera japonica Thunb. Using High Speed Counter-Current Chromatography (HSCCC and Prep-HPLC Guided by DPPH-HPLC Experiments

    Directory of Open Access Journals (Sweden)

    Daijie Wang

    2017-02-01

    Full Text Available In this work, the n-butanol extract from leaves of Lonicera japonica Thunb. (L. japonica was reacted with DPPH and subjected to a HPLC analysis for the guided screening antioxidants (DPPH-HPLC experiments. Then, nine antioxidants, including flavonoid glycosides and caffeoylquinic acid derivatives, were isolated and purified from leaves of L. japonica using high speed counter-current chromatography (HSCCC and prep-HPLC. The n-butanol extract was firstly isolated by HSCCC using methyl tert-butyl ether/n-butanol/acetonitrile/water (0.5% acetic acid (2:2:1:5, v/v, yielding five fractions F1, F2 (rhoifolin, F3 (luteoloside, F4 and F5 (collected from the column after the separation. The sub-fractions F1, F4 and F5 were successfully separated by prep-HPLC. Finally, nine compounds, including chlorogenic acid (1, lonicerin (2, rutin (3, rhoifolin (4, luteoloside (5, 3,4-Odicaffeoylquinic acid (6, hyperoside (7, 3,5-O-dicaffeoylquinic acid (8, and 4,5-O-dicaffeoylquinic acid (9 were obtained, respectively, with the purities over 94% as determined by HPLC. The structures were identified by electrospray ionization mass spectrometry (ESI-MS, 1H- and 13C-NMR. Antioxidant activities were tested, and the isolated compounds showed strong antioxidant activities.

  17. An Efficient Method for the Preparative Isolation and Purification of Flavonoid Glycosides and Caffeoylquinic Acid Derivatives from Leaves of Lonicera japonica Thunb. Using High Speed Counter-Current Chromatography (HSCCC) and Prep-HPLC Guided by DPPH-HPLC Experiments.

    Science.gov (United States)

    Wang, Daijie; Du, Ning; Wen, Lei; Zhu, Heng; Liu, Feng; Wang, Xiao; Du, Jinhua; Li, Shengbo

    2017-02-02

    In this work, the n-butanol extract from leaves of Lonicera japonica Thunb. (L. japonica) was reacted with DPPH and subjected to a HPLC analysis for the guided screening antioxidants (DPPH-HPLC experiments). Then, nine antioxidants, including flavonoid glycosides and caffeoylquinic acid derivatives, were isolated and purified from leaves of L. japonica using high speed counter-current chromatography (HSCCC) and prep-HPLC. The n-butanol extract was firstly isolated by HSCCC using methyl tert-butyl ether/n-butanol/acetonitrile/water (0.5% acetic acid) (2:2:1:5, v/v), yielding five fractions F1, F2 (rhoifolin), F3 (luteoloside), F4 and F5 (collected from the column after the separation). The sub-fractions F1, F4 and F5 were successfully separated by prep-HPLC. Finally, nine compounds, including chlorogenic acid (1), lonicerin (2), rutin (3), rhoifolin (4), luteoloside (5), 3,4-Odicaffeoylquinic acid (6), hyperoside (7), 3,5-O-dicaffeoylquinic acid (8), and 4,5-O-dicaffeoylquinic acid (9) were obtained, respectively, with the purities over 94% as determined by HPLC. The structures were identified by electrospray ionization mass spectrometry (ESI-MS), 1H- and 13C-NMR. Antioxidant activities were tested, and the isolated compounds showed strong antioxidant activities.

  18. Homegrown religious radicalization

    DEFF Research Database (Denmark)

    Khawaja, Iram

    It has been reported that a growing number of youngsters from Western Europe are engaging in conflicts motivated by religious and political conflicts in the Middle East. This paper explores the reasons behind this seemingly religious radicalization from the point of view of the youngsters...... and their families. Existing literature and ways of defining the social psychological process of radicalization will be discussed, and a theoretical framework based on a focus on (non-)belonging, Otherness and sense of community will be proposed. The framework will be utilized in an analysis of narratives from...... youngsters and parents of youngsters who have chosen a radicalized path in life. The paper will shed light on how the sense of and yearning for belonging and recognition have to be taken into account in our understanding of homegrown religious radicalization...

  19. Radical prostatectomy - discharge

    Science.gov (United States)

    ... to 6 months. You will learn exercises (called Kegel exercises) that strengthen the muscles in your pelvis. ... Radical prostatectomy Retrograde ejaculation Urinary incontinence Patient Instructions Kegel exercises - self-care Suprapubic catheter care Urinary catheters - ...

  20. Moderate and Radical Islam

    National Research Council Canada - National Science Library

    Rabasa, Angel

    2005-01-01

    This report presents the statement of Angel Rabasa, PhD, Senior Policy Analyst, The RAND Corporation, to the Committee on Armed Services, Defense Review Terrorism and Radical Islam Gap Panel, United...

  1. Free radical scavenging potential and HPTLC analysis of Indigofera tinctoria linn (Fabaceae

    Directory of Open Access Journals (Sweden)

    Sakthivel Srinivasan

    2016-04-01

    Full Text Available The objective of this study was to evaluate the free radical scavenging potential and high performance thin layer chromatography (HPTLC fingerprinting of Indigofera tinctoria (I. tinctoria. Phytochemical analysis was carried out using standard methods, and free radical scavenging activity of the plant was determined using 2,2-diphenyl-1-picrylhydrazy (DPPH, nitric oxide (NO and superoxide anion (O2− radical scavenging capacities. HPTLC plate was kept in CAMAG TLC Scanner 3 and the Rf values at fingerprint data were recorded by WINCATS software. Aqueous extract of I. tinctoria reliably showed the total phenolics (267.2±2.42 mg/g, flavonoids (75.43±3.36 mg/g and antioxidants (349.11±8.04 mg/g. The extract was found to have DPPH (52.08%, NO (23.12% and O2− (26.79% scavenging activities at the concentration of 250 μg/mL and the results were statistically significant compared with ascorbic acid standard (p<0.05. HPTLC results confirmed that the extract contained several potential active components such as phenols, flavonoids, saponins and terpenoids as the slides revealed multi-colored bands of varying intensities. This study confirmed that the plant had multipotential antioxidant and free radicals scavenging activities.

  2. Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

    Directory of Open Access Journals (Sweden)

    Suvankar Das

    2018-01-01

    Full Text Available Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH and the anion radical superoxide (·O2−. The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine 10. In general, U251, MCF7, NCI/ADR-RES, NCI-H460 and HT29 cells were least sensitive to the tested compounds and all compounds were considerably more toxic to the studied cancer cell lines than to the normal cell line HaCaT. The binding mode of the compounds and ctDNA was preferably via intercalation. In addition, these results were confirmed based on theoretical studies. Finally, a linear and exponential correlation between interaction constant (Kb and GI50 for several human cancer cell was observed.

  3. 1,1-Diphenyl-2-picrylhydrazyl radical scavenging activity and tyrosinase inhibitory effects of constituents of sugarcane molasses.

    Science.gov (United States)

    Takara, Kensaku; Otsuka, Keiko; Wada, Koji; Iwasaki, Hironori; Yamashita, Masatsugu

    2007-01-01

    In the course of our work into the use of cane by-products, we have studied the isolation and structural determination of bioactive compounds in sugarcane molasses. In this study, three stereo isomers of syringyl glycerol 3'-O-beta-D-glucopyranoside, three stereo isomers of guaiacyl glycerol 3'-O-beta-D-glucopyranoside, a syringyl glycerol 2'-O-beta-D-glucopyranoside, tachioside and a 2,3-dihydro-3,5-dihydroxy-6-methyl-4-(H)-pyran-4-one (DDMP) were isolated from the 25% methanol eluate by Amberlite XAD-2 column chromatography of sugarcane molasses. The structures of these compounds were determined on the basis of spectroscopic evidence. These isolated compounds were examined for their scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical species, and for their inhibitory activity against mushroom tyrosinase. All of the isolated compounds showed DPPH radical scavenging activity, while DDMP and tachioside showed mushroom tyrosinase inhibitory activity.

  4. Radical kinetics and characterization of the free radicals in gamma irradiated red pepper

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, M. E-mail: polat@hacettepe.edu.tr; Polat, M

    2001-12-01

    Kinetic behaviors and characterization of the natural and {gamma}-induced radicals in irradiated red pepper have been investigated by electron spin resonance (ESR) spectroscopy to explore the possibility of using this technique in detecting irradiated red pepper and to evaluate the eventual dosimetric features of this widely used food. Unirradiated samples exhibited a single resonance line centered at g=2.0050{+-}0.0005. Photo-exposure of the samples was found to increase the signal intensity. An increase in temperature created a drastic decrease in the concentration of natural radicals responsible for the single resonance line. Irradiation was observed to induce increases in the intensity of single resonance line (signal I) and a radiation specific doublet and/or triplet (signal II) also centered at g=2.0050 but detectable only at high spectrometer gains. The intensities of both signals increased with increasing radiation dose. The signals I and II were found to decay with different rates depending on the temperature. The results of a fitting procedure applied to the experimental signal decay curves and those obtained from room temperature spectra simulation calculations were used together to determine radical species and their spectral characteristics giving rise to the observed experimental spectra. Four radical species, three carbohydrate and one semiquinone radical assigned as radicals A, B, C and D, respectively, were found to best explain the experimental results. All the radicals show large g and hyperfine splitting anisotropies varying between g=2.0028-2.0062 and 1.07-2.58 mT, respectively. The half lives of the radicals were found to depend strongly on temperature. The activation energy calculated using temperature dependent half-life data were the highest for radical A (33.68 kcal/mol) and smallest for radical C (11.83 kcal/mol)

  5. Assessment of free-radical scavenging activity of Gypsophila pilulifera: assay-guided isolation of verbascoside as the main active component

    Directory of Open Access Journals (Sweden)

    Navdeep K. Chima

    Full Text Available Gypsophila pilulifera, Boiss & Heldr, Caryophyllaceae, is a perennial medicinal herb that grows in the southwestern region of Turkey. Except for only one report on the isolation of cytotoxic saponins from the underground parts of G. pilulifera, there are no published thorough phytochemical or bioactivity studies on this species. In the present study, the free-radical scavenging activity of extracts and fractions of the stems of G. pilulifera was evaluated, using a slightly modified and more precise version of the 2,2-diphenyl-1-picrylhydrazyl (DPPH assay, reported here for the first time. The DPPH assay-guided HPLC-PDA-purification of the active solid-phase extraction fraction (50% methanol in water of the methanolic extract exhibited verbascoside as the main free-radical scavenger present in this species. The structure of this active compound was resolved by spectroscopy, and the free-radical scavenging potential of verbascoside was determined.

  6. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  7. Rapid Screening and Preparative Isolation of Antioxidants from Alpinia officinarum Hance Using HSCCC Coupled with DPPH-HPLC Assay and Evaluation of Their Antioxidant Activities

    OpenAIRE

    Lei Fang; Hua Zhang; Jie Zhou; Yanling Geng; Xiao Wang

    2018-01-01

    An efficient method using high-speed counter-current chromatography (HSCCC) coupled with DPPH-HPLC assay has been developed for rapid screening and preparative isolation of antioxidants from ethyl acetate fraction of Alpinia officinarum Hance. Target-guided by DPPH-HPLC assay, two antioxidants, galangin and kaempferide, were targeted and further separated with purities of 99.3% and 98.5% by HSCCC using petroleum ether–ethyl acetate–methanol–water (0.8 : 1 : 1 : 0.8, v/v) as the solvent system...

  8. Changes in free-radical scavenging ability of kombucha tea during fermentation.

    Science.gov (United States)

    Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

    2008-07-01

    Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

  9. Laparoscopic radical trachelectomy.

    Science.gov (United States)

    Rendón, Gabriel J; Ramirez, Pedro T; Frumovitz, Michael; Schmeler, Kathleen M; Pareja, Rene

    2012-01-01

    The standard treatment for patients with early-stage cervical cancer has been radical hysterectomy. However, for women interested in future fertility, radical trachelectomy is now considered a safe and feasible option. The use of minimally invasive surgical techniques to perform this procedure has recently been reported. We report the first case of a laparoscopic radical trachelectomy performed in a developing country. The patient is a nulligravid, 30-y-old female with stage IB1 adenocarcinoma of the cervix who desired future fertility. She underwent a laparoscopic radical trachelectomy and bilateral pelvic lymph node dissection. The operative time was 340 min, and the estimated blood loss was 100mL. There were no intraoperative or postoperative complications. The final pathology showed no evidence of residual disease, and all pelvic lymph nodes were negative. At 20 mo of follow-up, the patient is having regular menses but has not yet attempted to become pregnant. There is no evidence of recurrence. Laparoscopic radical trachelectomy with pelvic lymphadenectomy in a young woman who desires future fertility may also be an alternative technique in the treatment of early cervical cancer in developing countries.

  10. DPPH scavenging, PRAP activities and essential oil composition of edible Lathyrus ochrus L. (Cyprus Vetch, Luvana) from Cyprus.

    Science.gov (United States)

    Polatoğlu, Kaan; Arsal, Seniha; Demirci, Betül; Başer, Kemal Hüsnü Can

    2015-01-01

    The essential oil of the aerial parts of edible Lathyrus ochrus L. was investigated by simultaneous GC, GC/MS analyses under the same conditions. Trace amount of oil (0.01> mL) obtained by hydro distillation of 200 g fresh plants was trapped in 1 mL n-hexane. Twenty components were detected representing 91.55 ± 0.56 % of the oil. The main components were phytol 49.39 ± 0.44 %, hexadecanoic acid 20.64 ± 0.89 % and pentacosane 4.20 ± 0.09 %. Essential oil solution (1% oil: n-hexane) afforded similar DPPH scavenging activity (9.28 ± 1.30 %) when compared with positive controls α-tocopherol (9.74 ± 0.21 %) and BHT (7.79 ± 0.26 %) at the same concentrations. Antioxidant activity of the oil was determined using a new HPTLC-PRAP assay. The oil afforded two fold higher reducing activity of phosphomolybdenum complex (594.85 ± 5.14 AU) when compared with positive controls α- tocopherol (271.10 ± 2.86 AU) and BHT (210.53 ± 1.81 AU) at the same concentration.

  11. Phytochemical constituents and in vitro radical scavenging activity of different Aloe species.

    Science.gov (United States)

    Lucini, Luigi; Pellizzoni, Marco; Pellegrino, Roberto; Molinari, Gian Pietro; Colla, Giuseppe

    2015-03-01

    The phytochemical profile of Aloe barbadensis Mill. and Aloe arborescens Mill. was investigated using colorimetric assays, triple quadrupole and time-of-flight mass spectrometry, focusing on phenolic secondary metabolites in the different leaf portions. Hydroxycinnamic acids, several characteristic anthrones and chromones, the phenolic dimer feralolide and flavonoids such as flavones and isoflavones were identified. The stable radical DPPH test and the ORAC assay were then used to determine the in vitro radical scavenging. The outer green rind was the most active, while the inner parenchyma was much less effective. The 5-methylchromones aloesin, aloeresin A and aloesone were the most active among the pure secondary metabolites tested. The results suggest that several compounds are likely to contribute to the overall radical scavenging activity, and indicate that leaf portion must be taken into account when the plant is used for its antioxidant properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Gangs, Terrorism, and Radicalization

    Directory of Open Access Journals (Sweden)

    Scott Decker

    2011-01-01

    Full Text Available What can street gangs tell us about radicalization and extremist groups? At first glance, these two groups seem to push the boundaries of comparison. In this article, we examine the important similarities and differences across criminal, deviant, and extremist groups. Drawing from research on street gangs, this article explores issues such as levels of explanation,organizational structure, group process, and the increasingly important role of technology and the Internet in the context of radicalization. There are points of convergence across these groups, but it is important to understand the differences between these groups. This review finds little evidence to support the contention that American street gangs are becoming increasingly radicalized. This conclusion is based largely on organizational differences between gangs and terror groups.

  13. Sexuality Following Radical Prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Serefoglu, Ege C; Albersen, Maarten

    2017-01-01

    INTRODUCTION: Radical prostatectomies can result in urinary incontinence and sexual dysfunction. Traditionally, these issues have been studied separately, and the sexual problem that has received the most focus has been erectile dysfunction. AIM: To summarize the literature on sexually related side...... effects and their consequences after radical prostatectomy and focus on the occurrence and management of problems beyond erectile dysfunction. METHODS: The literature on sexuality after radical prostatectomy was reviewed through a Medline search. Original research using quantitative and qualitative...... methodologies was considered. Priority was given to studies exploring aspects of sexuality other than erectile function. MAIN OUTCOME MEASURES: The prevalence, predictive factors, and management of post-prostatectomy sexual problems beyond erectile dysfunction. RESULTS: Most patients will develop urinary...

  14. Radical dematerialization and degrowth

    Science.gov (United States)

    Kallis, Giorgos

    2017-05-01

    The emission targets agreed in Paris require a radical reduction of material extraction, use and disposal. The core claim of this article is that a radical dematerialization can only be part and parcel of degrowth. Given that capitalist economies are designed to grow, this raises the question of whether, and under what circumstances, the inevitable `degrowth' can become socially sustainable. Three economic policies are discussed in this direction: work-sharing, green taxes and public money. This article is part of the themed issue 'Material demand reduction'.

  15. Homegrown religious radicalization

    DEFF Research Database (Denmark)

    Khawaja, Iram

    and their families. Existing literature and ways of thinking about the social psychological process of radicalization will be reviewed, such as social identity theory and transformative learning theory, and a theoretical framework based on a focus on belonging, recognition and the sense of community will be proposed....... The framework will be utilized in an analysis of narratives from youngsters and parents of youngsters who have chosen a radicalized path in life. The paper will shed light on how the sense of and yearning for belonging and recognition have to be taken into account in our understanding of homegrown religious...

  16. Muon substituted free radicals

    International Nuclear Information System (INIS)

    Burkhard, P.; Fischer, H.; Roduner, E.; Strub, W.; Gygax, F.N.; Brinkman, G.A.; Louwrier, P.W.F.; McKenna, D.; Ramos, M.; Webster, B.C.

    1984-01-01

    Spin polarized energetic positive muons are injected as magnetic probes into unsaturated organic liquids. They are implemented via fast chemical processes ( -10 s) in various molecules. Of particular interest among these are muonium substituted free radicals. The technique allows determination of accurate rate coefficients for fast chemical reactions of radicals. Furthermore, radiochemical processes occuring in picoseconds after injection of the muon are studied. Of fundamental interest are also the structural and dynamical implications of substituting a proton by a muon, or in other terms, a hydrogen atom by a muonium atom. Selected examples for each of these three types of experiments are given. (Auth.)

  17. Key role of chemical hardness to compare 2,2-diphenyl-1-picrylhydrazyl radical scavenging power of flavone and flavonol O-glycoside and C-glycoside derivatives.

    Science.gov (United States)

    Waki, Tsukasa; Nakanishi, Ikuo; Matsumoto, Ken-ichiro; Kitajima, Junichi; Chikuma, Toshiyuki; Kobayashi, Shigeki

    2012-01-01

    The antioxidant activities of flavonoids and their glycosides were measured with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH radical, DPPH(·)) scavenging method. The results show that free hydroxyl flavonoids are not necessarily more active than O-glycoside. Quercetin and kaempferol showed higher activity than apigenin. The C- and O-glycosides of flavonoids generally showed higher radical scavenging activity than aglycones; however, kaempferol C3-O-glycoside (astragalin) showed higher activity than kaempferol. In the radical scavenging activity of flavonoids, it was expected that OH substitutions at C3 and C5 and catechol substitution at C2 of B ring and intramolecular hydrogen bonding between OH at C5 and ketone at C3 would increase the activity; however, the reasons have yet to be clarified. We here show that the radical scavenging activities of flavonoids are controlled by their absolute hardness (η) and absolute electronegativity (χ) as a electronic state. Kaempferol and quercetin provide high radical scavenging activity since (i) OH substitutions at C3 and C5 strikingly decrease η of flavones, (ii) OH substitutions at C3 and C7 decrease χ and η of flavones, and (iii) phenol or o-catechol substitution at C2 of B ring decrease χ of flavones. The coordinate r(χ, η) as the electron state must be small to increase the radical scavenging activity of flavonoids. The results show that chemically soft kaempferol and quercetin have higher DPPH radical scavenging activity than chemically hard genistein and daidzein.

  18. The Synthesis and Evaluation of Novel Hydroxyl Substituted Chalcone Analogs with in Vitro Anti-Free Radicals Pharmacological Activity and in Vivo Anti-Oxidation Activity in a Free Radical-Injury Alzheimer’s Model

    Directory of Open Access Journals (Sweden)

    Ying Pan

    2013-01-01

    Full Text Available Alzheimer’s disease (AD pathogenesis involves an imbalance between free radical formation and destruction. In order to obtain a novel preclinical anti-AD drug candidate, we synthesized a series of novel hydroxyl chalcone analogs which possessed anti-free radical activity, and screened their effects on scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH and OH free radicals in vitro. Compound C7, 4,2'-dihydroxy-3,5-dimethoxychalcone was found to have potent activity in these anti-free radical activity tests. Further research revealed that C7 could elevate glutathione peroxidase (GSH-PX and super oxide dismutase (SOD levels and lower malonaldehyde (MDA level in vivo in the Alzheimer’s model. The indication of C7’s effect on AD needs further study.

  19. Substrate radical intermediates in soluble methane monooxygenase

    International Nuclear Information System (INIS)

    Liu Aimin; Jin Yi; Zhang Jingyan; Brazeau, Brian J.; Lipscomb, John D.

    2005-01-01

    EPR spin-trapping experiments were carried out using the three-component soluble methane monooxygenase (MMO). Spin-traps 5,5-dimethyl-1-pyrroline N-oxide (DMPO), α-4-pyridyl-1-oxide N-tert-butylnitrone (POBN), and nitrosobenzene (NOB) were used to investigate the possible formation of substrate radical intermediates during catalysis. In contrast to a previous report, the NADH-coupled oxidations of various substrates did not produce any trapped radical species when DMPO or POBN was present. However, radicals were detected by these traps when only the MMO reductase component and NADH were present. DMPO and POBN were found to be weak inhibitors of the MMO reaction. In contrast, NOB is a strong inhibitor for the MMO-catalyzed nitrobenzene oxidation reaction. When NOB was used as a spin-trap in the complete MMO system with or without substrate, EPR signals from an NOB radical were detected. We propose that a molecule of NOB acts simultaneously as a substrate and a spin-trap for MMO, yielding the long-lived radical and supporting a stepwise mechanism for MMO

  20. Violent Radicalization in Europe

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja

    2010-01-01

    and foiled plots inspired by militant Islamism have grabbed European and American headlines. This article identifies and discusses empirical studies of radicalization and points to the strengths as well as the weaknesses characterizing these studies. The aim is to take stock of the current state of research...

  1. Gnosticism and Radical Feminism

    DEFF Research Database (Denmark)

    Cahana, Jonathan

    2016-01-01

    and place demand an explanation; my attempt to do so also takes into account the important differences between the gnostic and the radical feminist postures, notably the latter belief in progress and the former nostalgia for an ungendered era. Both the similarities and the differences, however, may offer...

  2. Counter radicalization development assistance

    OpenAIRE

    van Hippel, Karin

    2006-01-01

    The paper reviews current research and practice and recommends strategies for development agencies working in the Arab and Muslim world. It builds on the basic assumption that the realization of the Millennium Development Goals will be vital to reduce support for terrorism in the long term. Within this overall framework, emphasis is placed on particular programs that could be specifically applied to counter radicalization.

  3. Electromeric rhodium radical complexes

    NARCIS (Netherlands)

    Puschmann, F.F.; Harmer, J.; Stein, D.; Rüegger, H.; de Bruin, B.; Grützmacher, H.

    2010-01-01

    Radical changes: One single P-Rh-P angle determines whether the odd electron in the paramagnetic complex [Rh(trop2PPh)(PPh3)] is delocalized over the whole molecule (see picture, blue) or is localized on the P—Rh unit (red). The two energetically almost degenerate electromers exist in a fast

  4. Radical Behaviorist Epistemology.

    Science.gov (United States)

    Zuriff, G. E.

    1980-01-01

    Various epistemological positions attributed to radical behaviorism are reviewed, and their problems are discussed. It is suggested that these problems may be resolved by interpreting the criterion of truth generated by a science of behavior as logically analagous to the set of ethical values generated by that science. (Author/DB)

  5. Influence of Free Radicals on the Intrinsic MRI Relaxation Properties.

    Science.gov (United States)

    Tain, Rong-Wen; Scotti, Alessandro M; Li, Weiguo; Zhou, Xiaohong Joe; Cai, Kejia

    2017-01-01

    Free radicals are critical contributors in various conditions including normal aging, Alzheimer's disease, cancer, and diabetes. Currently there is no non-invasive approach to image tissue free radicals based on endogenous contrast due to their extremely short lifetimes and low in vivo concentrations. In this study we aim at characterizing the influence of free radicals on the MRI relaxation properties. Phantoms containing free radicals were created by treating egg white with various H 2 O 2 concentrations and scanned on a 9.4 T MRI scanner at room temperature. T 1 and T 2 relaxation maps were generated from data acquired with an inversion recovery sequence with varied inversion times and a multi-echo spin echo sequence with varied echo times (TEs), respectively. Results demonstrated that free radicals express a strong shortening effect on T 1 , which was proportional to the H 2 O 2 concentration, and a relatively small reduction in T 2 (free radicals was estimated to be in the pM range that is within the physiological range of in vivo free radical expression. In conclusion, the free radicals show a strong paramagnetic effect that may be utilized as an endogenous MRI contrast for its non-invasive in vivo imaging.

  6. Antioxidant capacities of mannans and glucans are related to their susceptibility of free radical degradation.

    Science.gov (United States)

    Machová, Eva; Bystrický, Slavomír

    2013-10-01

    Microbial and plant polysaccharides in nature are frequently exposed to oxidative burst. They may act as antioxidants buffering the radical attack. This paper presents antioxidant properties of prepared yeast mannans, commercial β-glucans as well as the chemically prepared carboxymethylated β-glucan (CM-glucan). The hydroxyl radical antioxidant assay and the DPPH radical-scavenging assay were used. Yeast mannans and β-glucans (1.6 mg mL(-1)) showed antioxidant capacities against OH(·) up to 14.1%, while CM-glucan was significantly higher antioxidant (65.4%). In the DPPH(·) assay, the antioxidant capacities of yeast mannans and β-glucans (1.0 mg mL(-1)) were lower and reached up to ~6.5%. All polysaccharides tested were effectively degraded by OH(·) and the presence of salicylate considerably inhibited their degradation. Measure of Fe(2+) chelation revealed less than 13.1% effectivity for all polysaccharides. In all antioxidant and degradation experiments the yeast mannans showed very similar results to commercial β-glucans. The antioxidant capacities of polysaccharides may be assessed by simple HPLC monitoring. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Radical-scavenging compounds from olive tree (Olea europaea L.) wood.

    Science.gov (United States)

    Pérez-Bonilla, Mercedes; Salido, Sofía; van Beek, Teris A; Altarejos, Joaquín

    2014-01-08

    The purpose of this study was to complete knowledge on the chemical composition and radical-scavenging activity of olive tree wood. Two new monoterpene glycosides, (-)-oleuropeic acid 6'-O-α-D-glucopyranosyl ester (6a) and (-)-perillic acid 1'-O-β-D-primeverosyl ester (8), together with the known compounds (-)-oleuropeic acid (1), (-)-olivil (2), the aldehydic form of oleuropein aglycone (3), (+)-1-hydroxypinoresinol 1-O-β-D-glucopyranoside (4), (-)-oleuropeic acid 1'-O-β-D-glucopyranosyl ester (5), (-)-oleuropeic acid 6'-O-β-D-glucopyranosyl ester (6b), and (-)-olivil 4-O-β-D-glucopyranoside (7) were isolated from an ethyl acetate extract. The radical scavengers found (2-4 and 7) were detected and isolated with the help of the online HPLC-DAD-DPPH/ABTS technique. Compounds 2-4 and 7 displayed a higher antioxidative effect against the free radical DPPH than the reference BHT and lower than hydroxytyrosol, whereas compounds 1, 5, 6a, 6b, and 8 showed no activity.

  8. Phytochemical composition and radical scavenging activities of watermelon (Citrullus lanatus seed constituents

    Directory of Open Access Journals (Sweden)

    O. L. Otutu

    2016-01-01

    Full Text Available It is a known fact that antioxidant phytochemicals in foods have many health benefits including prevention of various diseases associated with oxidative stress such as cancer, cardiovascular disease, neuro-degeneration and diabetes. Watermelon seed constituents (whole meal, shelled and shells flours were evaluated for phytochemical components and in vitro antioxidant activity to determine the potential practical applications in food and other related areas. Antioxidant activity was investigated by measuring its DPPH (2,2-diphenyl-2-picryl hydrazyl and ABTS (2, 2’-azinobis-3-ethylbenzothiozoline- 6-sulphonic acid radical scavenging ability as well as FRAP method (ferric reducing power. Quantitative estimation of the constituents showed cardiac glycosides (9.94-14.35 mg/g and saponins (11.62-32.48 mg/g as the most concentrated phytochemicals in the constituents, while alkaloids (47.2-95.8 mg/g, total phenol (5.63-8.40 mg GAE/g, flavonoids 3.51-7.76 mg QE/g. A positive radical scavenging ability of the constituents against ABTS and DPPH free radicals ranged from 0.02 to 0.04 mg Trolox equivalent /g seed flour and 39.89 to 61.11 mg ascorbic acid equivalent /g seed flour respectively. There was a considerable ferric reducing power and higher activity was observed in whole meal than shelled seeds and shells. The significant antioxidant capacities of the seed constituents underline the potential source of natural antioxidants and bioactive compounds for therapeutic purposes.

  9. Phytochemical screening, free radical scavenging, antioxidant activity and phenolic content of Dodonaea viscosa

    Directory of Open Access Journals (Sweden)

    Riaz Tauheeda

    2012-01-01

    Full Text Available The purpose of this study was to evaluate the antioxidant potential of Dodonaea viscosa Jacq. Methanolic extract of the plant was dissolved in distilled water and partitioned with n-hexane, chloroform, ethyl acetate and nbutanol sequentially. Phytochemical screening showed presence of phenolics, flavonoides and cardiac glycosides in large amount in chloroform, ethyl acetate and n-butanol fraction. The antioxidant potential of all these fractions and remaining aqueous fraction was evaluated by four methods: 1,1-Diphenyl-2-picrylhydrazyl (DPPH free radical scavenging activity, total antioxidant activity, Ferric Reducing Antioxidant Power (FRAP assay and ferric thiocyanate assay along with determination of their total phenolics. The results revealed that ethyl acetate soluble fraction exhibited highest percent inhibition of DPPH radical as compared to other fractions. It showed 81.14 ± 1.38% inhibition of DPPH radical at a concentration of 60 μg/ml. The IC50 of this fraction was found to be 33.95 ± 0.58 μg/ml, relative to butylated hydroxytoluene (BHT, having IC50 of 12.54 ± 0.89 μg/mL. It also showed highest FRAP value (380.53 ± 0.74 μM of trolox equivalents as well as highest total phenolic contents (208.58 ± 1.83 GAE μg/g and highest value of inhibition of lipid peroxidation (58.11 ± 1.49% at concentration of 500 μg/ml as compared to the other studied fractions. The chloroform fraction showed highest total antioxidant activity i.e.1.078 ± 0.59 (eq. to BHT.

  10. Radical Change by Entrepreneurial Design

    National Research Council Canada - National Science Library

    Roberts, Nancy C

    1998-01-01

    This article offers a conceptual framework to understand radical change. It opens with a typology that defines change in terms of its pace and scope, and defines radical change as the swift transformation of an entire system...

  11. Evaluation of free radical scavenging and anti-oxidative capacity of polydatin-nanostructured lipid carriers

    Science.gov (United States)

    Meng, Xiang-Ping; Shi, Fan; Li, Hai-Jie; Yin, Li-De; Wang, Yi-Fei; Wang, Zhi-ping; Chen, Tong-sheng

    2016-10-01

    Cellular damage induced by free-radicals like reactive oxygen species has been implicated in several diseases. 2, 2-azobis(2-amidino-propane) dihydrochloride(AAPH) generates two potent ROS capable of inducing lipid peroxidation: alkoxy radical(RO-) and peroxy radical (ROO-). These radicals are similar to those that are physiologically active and thus might initiate a cascade of intracellular toxic events leading to oxidation, lipid peroxidation, DNA damage and subsequent cell death. Hence naturally anti-oxidant play a vital role in combating these conditions. In this study, polydatin loaded nanostructured lipid carriers (Pol-NLC) was prepared by hot melting and then high pressure homogenization technique. The effects of Pol-NLC on free radical scavenging and anti-oxidative capacity is investigated. The particle size and zeta potential of Pol-NLC were 113.9 +/- 1.1 nm and -16.3 1 +/- 0.27 mV, respectively. By free radical scavenging assays, the IC50 value of Pol-NLC were 28.71, 9.83 μg/mL with DPPH, ABTS assay respectively, and 0.143 mg ferrous sulfate/1 mg Pol-NLC with FRAP assay. These results indicated that the antioxidant properties of Pol-NLC hold great potential used as an alternative to more toxic synthetic anti-oxidants as an additive in food, cosmetic and pharmaceutical preparations for the oxidative diseases treatment.

  12. Radical Welfare State Retrenchment: A Comparative Analysis

    DEFF Research Database (Denmark)

    Starke, Peter

    In this study, Peter Starke confronts one of the most fiercely contested issues in current political debates: how is the retrenchment of the welfare state possible when popular support for it remains strong throughout the OECD world? Traditionally, challenges to the welfare state were seen...... with Sweden and Germany, Starke argues that radical retrenchment is not the result of historical accident or political will but that it is due to a particular constellation of partisan and institutional factors....

  13. Free radical scavenging activity-guided isolation of a diterpenoid from Plectranthus punuctatus.

    Science.gov (United States)

    Kebede, Wossen; Bisrat, Daniel; Asres, Kaleab

    2011-09-01

    Free radical scavenging activity-guided investigation of the acetone extract of Plectranthus punuctatus (L'Her) (Lamiaceae) resulted in the isolation of a novel diterpenoid 3,11,12,14,19-pentahydroxy-5,8,11,13-abietatraen-7-pyran[4,6]-16-dione whose structure was elucidated based on spectral evidence. The isolated compound showed a significant antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and deoxyribose degradation assays with IC50 values of 9.65 microg/mL and 5.25 microg/mL, respectively.

  14. LC/PDA/ESI-MS Profiling and Radical Scavenging Activity of Anthocyanins in Various Berries

    Directory of Open Access Journals (Sweden)

    Jun-ichiro Nakajima

    2004-01-01

    Full Text Available Anthocyanin extracts of two blueberries, Vaccinium myrtillus (bilberry and Vaccinium ashei (rabbiteye blueberry, and of three other berries, Ribes nigrum (black currant, Aronia melanocarpa (chokeberry, and Sambucus nigra (elderberry, were analyzed by high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization - mass spectrometry (LC/PDA/ESI-MS. Both bilberry and rabbiteye blueberry contained 15 identical anthocyanins with different distribution patterns. Black currant, chokeberry, and elderberry contained 6, 4, and 4 kinds of anthocyanins, respectively. The radical scavenging activities of these berry extracts were analyzed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH. All these extracts showed potent antiradical activities.

  15. Antioxidant Composition of a Selection of Italian Red Wines and Their Corresponding Free-Radical Scavenging Ability

    Directory of Open Access Journals (Sweden)

    Claudio Cassino

    2016-01-01

    Full Text Available This study correlates the antioxidant composition profiles and the overall antioxidant capacities of 36 Italian red wine samples. The samples were fully characterized by chromatographic and spectrophotometric techniques. The overall antioxidant capacity was determined by titrating a solution of the semistable free radical DPPH (1,1-diphenyl-2-picrylhydrazyl with each wine sample followed by Electron Paramagnetic Resonance (EPR spectroscopy and then measuring the resulting decrease in DPPH-signal. The antioxidant activities of the samples were expressed as (+-catechin equivalents and related to their antioxidant composition profiles. Samples with a high polyphenol content showed a high DPPH scavenging ability as well. Seven well-defined groups, mainly constituted by wines coming from the same cultivar, were evidenced by PCA analysis. Alcohol content and pH did not influence the wine DPPH scavenging ability. The most important variables contributing to the wines’ antioxidant power are total flavonoid, total phenol, and proanthocyanidin indices together with fertaric acid, trans-caftaric acid, trans-coutaric acid, and both quercetin glucoside and quercetin glucuronide. EPR is demonstrated to be faster than the other analytical methods (spectrophotometric and chromatographic analyses to determine the wine overall antioxidant activity.

  16. Site reactivity in the free radicals induced damage to leucine residues: a theoretical study.

    Science.gov (United States)

    Medina, M E; Galano, A; Alvarez-Idaboy, J R

    2015-02-21

    Several recent computational studies have tried to explain the observed selectivity in radical damage to proteins. In this work we use Density Functional Theory and Transition State Theory including tunnelling corrections, reaction path degeneracy, the effect of diffusion, and the role of free radicals to get further insights into this important topic. The reaction between a leucine derivative and free radicals of biological significance, in aqueous and lipid media, has been investigated. Both thermochemical and kinetic analyses, in both hydrophilic and hydrophobic environments, have been carried out. DPPH, ˙OOH, ˙OOCH3, ˙OOCH2Cl, ˙OOCHCl2 and ˙OOCHCH2 radicals do not react with the target molecule. The reactions are proposed to be kinetically controlled. The leucine gamma site was the most reactive for the reactions with ˙N3, ˙OOCCl3, ˙OCH3, ˙OCH2Cl, and ˙OCHCl2 radicals, with rate constants equal to 1.97 × 10(5), 3.24 × 10(4), 6.68 × 10(5), 5.98 × 10(6) and 8.87 × 10(8) M(-1) s(-1), respectively, in aqueous solution. The ˙Cl, ˙OH and ˙OCCl3 radicals react with leucine at the beta, gamma, and delta positions at rates close to the diffusion limit with the alpha position which is the slowest path and the most thermodynamically favored. The presented results confirm that the Bell-Evans-Polanyi principle does not apply for the reactions between amino acid residues and free radicals. Regarding the influence of the environment on the reactivity of the studied series of free radicals towards leucine residues, it is concluded that hydrophilic media slightly lower the reactivity of the studied radicals, compared to hydrophobic ones, albeit the trends in reactivity are very similar.

  17. Free radical explosive composition

    Science.gov (United States)

    Walker, Franklin E.; Wasley, Richard J.

    1979-01-01

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a getter additive comprising a compound or mixture of compounds capable of capturing or deactivating free radicals or ions under mechanical or electrical shock conditions and which is not an explosive. Exemplary getter additives are isocyanates, olefins and iodine.

  18. Determination of Radical Scavenging Activity and Total Phenols of Wine and Spices: A Randomized Study.

    Science.gov (United States)

    Lugemwa, Fulgentius Nelson; Snyder, Amanda L; Shaikh, Koonj

    2013-07-25

    Thirty eight bottles of red wine (Carbanet Sauvignon) were randomly selected based on vintage, region, price, and age (number of months in a barrel). The total phenolic content of each wine was determined using Folin-Ciocalteau assay. The radical scavenging activity was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Apart from a few bottles that exhibited above average radical scavenging activity and phenolic content, there was no good correlation of those two quantities with region, price or vintage. The average phenolic amount was 2874 mg/L. The lowest phenolic content was found to be 1648 mg/L for an eight dollar wine. Wine with the highest amount of phenol of 4495 mg/L was a 2007, nine dollar bottle from South America. High amount of phenols did not translate into high radical scavenging activity. Barrel-aging did not increase the amount of phenols or the radical scavenging activity of wine. In order to discover new and potent sources of antioxidants from plants, the following spices were studied: ginger, cilantro, cumin, anise, linden, eucalyptus, marjoram, oregano, sage, thyme and rosemary. Whole spices were crushed and extracted for 96 h at room temperature using a combination of ethyl acetate, ethyl alcohol and water in the ratio of 4.5:4.5:1 (v/v/v). The radical scavenging activity of extracts was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. The total phenolic content of each spice was also determined using the Folin-Ciocalteau assay. Eucalyptus was found to be the most potent antioxidant with an LC50 of 324.1 mg of phenol/L, followed by marjoram with an LC50 of 407.5 mg of phenol/L, and rosemary with an LC50 of 414.0 mg/L. The least potent antioxidants were ginger and cilantro with LC50 of 7604 mg/L of phenol and 7876 mg of phenol/L, respectively.

  19. Analysis of phenolic compounds and radical scavenging activity of Echinacea spp.

    Science.gov (United States)

    Pellati, Federica; Benvenuti, Stefania; Magro, Lara; Melegari, Michele; Soragni, Fabrizia

    2004-04-16

    The aim of this study was to set up and validate an RP-LC method with DAD-detection to quantify caffeic acid derivatives in various Echinacea spp. Samples were extracted with 80% methanol. The analyses were carried out on a Lichrospher RP-18 column (125 mm x 4 mm i.d., 5 microm), with a mobile phase gradient, which increases the acetonitrile level in a phosphoric acid solution (0.1%). The flow rate was 1.5 ml/min. Detection was set at 330 nm. This method allowed the identification and quantification of caftaric acid, chlorogenic acid, caffeic acid, cynarin, echinacoside and cichoric acid in Echinacea roots and derivatives. The total phenolic content was 10.49 mg/g for E. angustifolia, 17.83 mg/g for E. pallida and 23.23 mg/g for E. purpurea. Among Echinacea commercial herbal medicines, a certain variability in the concentrations of phenolic compounds was observed. The radical scavenging activity of Echinacea methanolic extracts was evaluated in vitro with a spectrophotometric method based on the reduction of an alcoholic 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical solution at 517 nm in the presence of a hydrogen donating antioxidant. As for pure compounds, echinacoside had the highest capacity to quench DPPH* radicals (EC50 = 6.6 microM), while caftaric acid had the lowest (EC50 = 20.5 microM). The average EC50 values for E. purpurea, E. pallida and E. angustifolia were 134, 167 and 231 microg/ml, respectively. The radical scavenging activity of Echinacea root extracts reflected their phenolic composition. The results indicate that Echinacea roots and derivatives are a good source of natural antioxidants and could be used to prevent free-radical-induced deleterious effects.

  20. Radical distinction : Support for radical left and radical right parties in Europe

    NARCIS (Netherlands)

    Rooduijn, Matthijs; Burgoon, Brian; van Elsas, Erika J.; van de Werfhorst, Herman G.

    2017-01-01

    Support for radical parties on both the left and right is on the rise, fueling intuition that both radicalisms have similar underpinnings. Indeed, existing studies show that radical left and right voters have overlapping positions and preferences. In this article, however, we focus on the

  1. Evaluation of antitumor, immunomodulatory and free radical scavenging effects of a new herbal prescription seaweed complex preparation

    Science.gov (United States)

    Liu, Xin; Shao, Changlun; Kong, Wenwen; Fang, Yuchun; Wang, Changyun

    2013-09-01

    Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs, and it has been used for treatment of lung cancer, liver cancer and digestive cancer. However, little information is available about the pharmacodynamic basis. The antitumor, immunomodulatory and free radical scavenging effects of SCP were evaluated in this study. Transplanted tumor in vivo method was used to determine the antitumor effect. The effects on splenocyte proliferation and phagocytosis of macrophages in tumor-bearing mice were measured by the MTT method and the phagocytizing cock red blood cell (CRBC) method respectively. The scavenging activities of SCP on DPPH and hydroxyl radicals in vitro were investigated. It was found that the medium-dose and high-dose of SCP could significantly inhibit the growth of transplanted hepatic tumor of murine hepatocarcinoma cell line H22, and promote proliferation of splenocytes and phagocytosis of macrophages. SCP possessed noticeable scavenging activities on DPPH and hydroxyl radicals. The antitumor effects of SCP might be achieved by improving immune system and scavenging free radicals, which is in accordance with the viewpoint of traditional Chinese medicine in promoting the body resistance and eliminating pathogenic factors for cancer treatment.

  2. Excellent combination of HPLC-RSD-DAD-ESI/MS and HSCCC experiments to screen and identify radical scavengers from Neo-Taraxacum siphonanthun

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xinyu; Shi, Shuyun; Zhang, Yuping; Chen, Xiaoqing, E-mail: jiangxinyu@mail.csu.edu.c [Central South University, Changsha (China). School of Chemistry and Chemical Engineering

    2010-07-01

    Our previous research found that the crude extract of Neo-T. siphonanthun exhibited an effective DPPH (1,1-diphenyl-2-picryhydrazyl) radical scavenging activity. In this study an online rapid screening method, high-performance liquid chromatography-radical scavenging detection-diode array detector-electrospray ionization mass spectrometry (HPLC-RSD- DAD-ESI/MS) system, was developed for screening individual antioxidants from the most active fraction. Accordingly, three isomeric derivatives were detected. The target active compounds were isolated by highspeed counter-current chromatography (HSCCC) with the purity over 99%, and were identified as luteolin-3'-O-{beta}-D-glucopyranoside (1), luteolin-7-O-{beta}-D-glucopyranoside (2) and luteolin-4'- O-{beta}-D-glucopyranoside (3) by analysis of its off-line nuclear magnetic resonance (NMR) spectra. Antioxidant activity of three compounds was assessed by off-line DPPH assay, and all of them showed potent activity. (author)

  3. Phenolic profile and free radical-scavenging activity of Cabernet Sauvignon wines of different geographical origins from the Balkan region.

    Science.gov (United States)

    Radovanović, Blaga C; Radovanović, Aleksandra N; Souquet, Jean-Marc

    2010-11-01

    The phenolic profile, determined by the relative proportions of different phenolic compounds, is characteristic for each grape variety and its corresponding wine. The aim of this study was to determine the phenolic and hydroxycinnamate acid, flavan-3-ol and flavonol contents and free radical-scavenging activity of single-cultivar (Cabernet Sauvignon) wines from selected Balkan vineyard regions by spectrophotometric methods and high-performance liquid chromatography with photodiode array and fluorescence detection. The contents of phenolic compounds varied depending on the agroclimatic factors and oenological practices of the vineyard region. The antioxidant activity of wine samples was estimated by their ability to scavenge the stable 2,2'-diphenyl-1-picrylhydrazyl free radical (DPPH). All wines showed high DPPH-scavenging activity (70.03-83.53%, mean 73.76%). Significant correlations between catechin (R(2) = 0.8504) and quercetin (R(2) = 0.8488) concentrations and DPPH-scavenging ability of the wines were found. The concentrations of the main components catechin and quercetin can be used as biochemical markers for the authentication of red grape cultivars and their corresponding single-cultivar wines. 2010 Society of Chemical Industry

  4. Phenolic Contents and Antioxidant Potential of Crataegus Fruits Grown in Tunisia as Determined by DPPH, FRAP, and β-Carotene/Linoleic Acid Assay

    Directory of Open Access Journals (Sweden)

    Farouk Mraihi

    2013-01-01

    Full Text Available Crataegus fruit is one of most important fruits in Tunisian flora. Some fruits of this genus are edible. This study was undertaken in order to examine the benefits of these fruits in human health and their composition of antioxidants including total polyphenol, flavonoids, proanthocyanidins content, and total anthocyanins. The antioxidative properties of the ultrasonic methanolic extract were assessed by different in vitro methods such as the FRAP, DPPH, and β-carotene/linoleic acid assay. We concluded that peel fraction of red fruits possessed relatively high antioxidant activity and might be a rich source of natural antioxidants in comparison with the pulp and seed fruit extract. The results also showed that hawthorn yellow fruit presents lower amounts of phenolic content, absence of anthocyanins, and less antioxidant capacity. Most of peel and seed fractions were stronger than the pulp fractions in antioxidant activity based on their DPPH IC50, FRAP values, and results of β-carotene/linoleic acid. The total phenolic compounds contents were also highly correlated with the DPPH method and the FRAP assay.

  5. Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L.), J. oxycedrus (L.), J. phoenicea (L.) and Tetraclinis articulata (L.)

    OpenAIRE

    El Jemli, Meryem; Kamal, Rabie; Marmouzi, Ilias; Zerrouki, Asmae; Cherrah, Yahia; Alaoui, Katim

    2016-01-01

    Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic ...

  6. Catalysis of Radical Reactions: A Radical Chemistry Perspective.

    Science.gov (United States)

    Studer, Armido; Curran, Dennis P

    2016-01-04

    The area of catalysis of radical reactions has recently flourished. Various reaction conditions have been discovered and explained in terms of catalytic cycles. These cycles rarely stand alone as unique paths from substrates to products. Instead, most radical reactions have innate chains which form products without any catalyst. How do we know if a species added in "catalytic amounts" is a catalyst, an initiator, or something else? Herein we critically address both catalyst-free and catalytic radical reactions through the lens of radical chemistry. Basic principles of kinetics and thermodynamics are used to address problems of initiation, propagation, and inhibition of radical chains. The catalysis of radical reactions differs from other areas of catalysis. Whereas efficient innate chain reactions are difficult to catalyze because individual steps are fast, both inefficient chain processes and non-chain processes afford diverse opportunities for catalysis, as illustrated with selected examples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The role of melanin as protector against free radicals in skin and its role as free radical indicator in hair

    Science.gov (United States)

    Herrling, Thomas; Jung, Katinka; Fuchs, Jürgen

    2008-05-01

    Throughout the body, melanin is a homogenous biological polymer containing a population of intrinsic, semiquinone-like radicals. Additional extrinsic free radicals are reversibly photo-generated by UV and visible light. Melanin photochemistry, particularly the formation and decay of extrinsic radicals, has been the subject of numerous electron spin resonance (ESR) spectroscopy studies. Several melanin monomers exist, and the predominant monomer in a melanin polymer depends on its location within an organism. In skin and hair, melanin differs in content of eumelanin or pheomelanin. Its bioradical character and its susceptibility to UV irradiation makes melanin an excellent indicator for UV-related processes in both skin and hair. The existence of melanin in skin is strongly correlated with the prevention against free radicals/ROS generated by UV radiation. Especially in the skin melanin (mainly eumelanin) ensures the only natural UV protection by eliminating the generated free radicals/ROS. Melanin in hair can be used as a free radical detector for evaluating the efficacy of hair care products. The aim of this study was to investigate the suitability of melanin as protector of skin against UV generated free radicals and as free radical indicator in hair.

  8. Manipulating radicals: Using cobalt to steer radical reactions

    OpenAIRE

    Chirilă, A.

    2017-01-01

    This thesis describes research aimed at understanding and exploiting metallo-radical reactivity and explores reactions mediated by square planar, low-spin cobalt(II) complexes. A primary goal was to uncover novel reactivity of discrete cobalt(III)-bound carbene radicals generated upon reaction of the cobalt(II) catalysts with carbene precursors. Another important goal was to replace cobalt(II)-porphyrin catalysts with cheaper and easier to prepare metallo-radical analogues. Therefore the cata...

  9. Polyphenolic Compounds and Free Radical Scavenging Activity in Eight Lamiaceae Herbs of Manipur

    Directory of Open Access Journals (Sweden)

    Sandhyarani Devi KHOMDRAM

    2011-05-01

    Full Text Available Eight plants of Lamiaceae under subfamily Nepetoideae found in Manipur, India were selected for estimation of their polyphenolic compounds and free radical scavenging activity which is expressed on dry weight basis. In this present study, the total phenol and flavonoid contents as well as the free radical scavenging activity were studied using spectrophotometric method. The total phenol content was determined based on Folin-Ciocalteau reagent, flavonoid was determined by aluminium chloride spectrophotometric method and tannin by Folin Dennis Method. The free radical scavenging activity was determined by using DPPH radical which is expressed as IC50 (μg/ml. The total phenolic content varied from 21.39±0.927 to 46.28±0.543 mg/g, flavonoids content in the selected samples varied from 13.30±0.684 to 26.03±0.217 mg/g and tannin content varied from 8.72±0.160 to 17.04±0.206 mg/g. The free radical scavenging activity among the selected samples varied from 11.67±0.221 to 38.29±0.532 μg/ml. The correlation between the free radical scavenging activity with total phenol content (R2=0.511, with flavonoids (R2=0.241 and with tannin (R2=0.690 was calculated and maximum correlation value was found between tannin content and the free radical scavenging activity of the plant samples. The result supports that tannins were more responsible for free radical scavenging activity in the presently selected plants.

  10. Composition of Essential Oil, Radical Scavenging and Antibacterial Properties of Interspecific Hybrid Thymus × oblongifolius Opiz

    Directory of Open Access Journals (Sweden)

    Kristina Lo žienė

    2012-01-01

    Full Text Available Radical scavenging and antibacterial properties of thyme extracts isolated from the two different Thymus × oblongifolius Opiz samples (TO1 and TO2 were studied. The oil of the TO1 was constituted mainly of hydrocarbon terpenes (83.4%, while the oil of the TO2 was composed mainly of oxygenated compounds with a -terpenyl acetate (37.9% being the major one. The extracts isolated with hexane, acetone and ethanol from the whole and deodorized herb were tested for their radical scavenging capacity (RSC in the model reaction systems containing stable radical DPPH • and cation radical ABTS •+. The extracts isolated with ethanol from undeodorized herb possessed the strongest RSC, while hexane extracts were not active. Undeodorized acetone extracts of the TO1 possessed higher RSC than those of the TO2, while undeodorized ethanol extracts of the TO2 were stronger radical scavengers than similar extracts of the TO1. The antibacterial activity of the extracts tested by using seven food pathogenic species depended on the species, extract concentration and extract type. Bacillus cereus, Staphylococcus aureus and St. epidermidis were more sensitive to plant extracts than Micrococcus luteus, Esherichia coli, Salmonella typhimurium and Enterobacter aerogenes.

  11. EPR study of free radicals in bread

    Science.gov (United States)

    Yordanov, Nicola D.; Mladenova, Ralitsa

    2004-05-01

    The features of the recorded EPR spectra of paramagnetic species formed in bread and rusk are reported. The appearance of free radicals in them is only connected with their thermal treatment since the starting materials (flour and grains) exhibit very weak EPR signal. The obtained EPR spectra are complex and indicate that: (i) the relative number of paramagnetic species depends on the temperature and treating time of the raw product; (ii) the g-values are strongly temperature dependent with a tendency to coincide at t≥220 °C. Because of the relatively low (150-220 °C) temperature of thermal treatment, the studied free radicals can be assumed to appear in the course of the browning (Maillard) reaction and not to the carbonization of the material.

  12. Radical Scavenging Activity of the Essential Oil of Silver Fir (Abies alba).

    Science.gov (United States)

    Yang, Seun-Ah; Jeon, Sang-Kyung; Lee, Eun-Jung; Im, Nam-Kyung; Jhee, Kwang-Hwan; Lee, Sam-Pin; Lee, In-Seon

    2009-05-01

    The essential oil of silver fir (Abies alba) is known to help respiratory system and have easing and soothing effect for muscle. In the present study, we investigated the chemical composition, cytotoxicity and its biological activities of silver fir (Abies alba) essential oil. The composition of the oil was analyzed by GC-MS and bornyl acetate (30.31%), camphene (19.81%), 3-carene (13.85%), tricyclene (12.90%), dl-limonene (7.50%), alpha-pinene (2.87%), caryophyllene (2.18%), beta-phellandrene (2.13%), borneol (1.74%), bicyclo[2.2.1]hept-2-ene,2,3-dimethyl (1.64%) and alpha-terpinene (1.24%) were the major components in the oil. The results tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that the oil showed no cytotoxic effect, at concentrations of 1 and 5%, for as long as 24 and 3 h, respectively. The antiradical capacity was evaluated by measuring the scavenging activity of the essential oil on the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals. The oil was able to reduce the both radicals dose-dependently, and the concentration required for 50% reduction (RC(50)) against DPPH radicals (2.7 +/- 0.63%) was lower than ABTS radicals (8.5 +/- 0.27%). The antibacterial activity of the oil was also evaluated using disc diffusion method against Staphylococcus aureus, Streptococcus mutans, Listeria monocytogenes, Acinetobacter baumannii, Escherichia coli, and Vibrio parahaemolyticcus. The oil exhibited no antibacterial activity against all the bacterial strains tested except S. aureus of mild activity.

  13. Screening and Identifying Antioxidative Components in Ginkgo biloba Pollen by DPPH-HPLC-PAD Coupled with HPLC-ESI-MS2.

    Science.gov (United States)

    Qiu, Jiying; Chen, Xiangyan; Netrusov, A I; Zhou, Qingxin; Guo, Danyang; Liu, Xiaoyong; He, Hailun; Xin, Xue; Wang, Yifen; Chen, Leilei

    2017-01-01

    The Ginkgo biloba is one of ancient trees that exists from billions of years ago, its leaf and nut are used as herbs and foods in China, while so far its pollen does not have any application except pollination. In order to evaluate the antioxidant activity of Ginkgo biloba pollen, and rapidly screen its antioxidative components, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, total flavonoid, total phenol, and proanthocyanidin of Ginkgo biloba pollen were determined and compared with those of Ginkgo biloba leaf and nut, and the off-line DPPH-HPLC-PAD and HPLC-ESI-MS2 were applied for screening and identifying the antioxidant flavonoids in Ginkgo biloba pollen. The results showed that the DPPH scavenging ability of Ginkgo biloba pollen was much higher than Ginkgo biloba nut, but lower than Ginkgo biloba leaf, while the total content of flavonoid in Ginkgo biloba pollen was approximately 4.37 times higher than in Ginkgo biloba leaf. Further studies found that the major flavonol aglycone in Ginkgo biloba pollen was kaempferol, which accounted for 96.71% of the total aglycones (includes quercetin, kaempferol and isorhamnetin), and the main flavonoid components in Ginkgo biloba pollen were flavonoid glycosides. Finally, ten antioxidant peaks were screened and identified to be flavonoids (including kaempferol and nine flavonoid glycosides), so flavonoids were likely to be the main antioxidant components in GP, and among them, three novel kaempferol glycosides (peaks 1, 2, and 3) were found in Ginkgo biloba pollen for the first time, which had never been found in Ginkgo biloba.

  14. Free radicals and polarized targets

    Science.gov (United States)

    Bunyatova, E. I.

    2004-06-01

    Many free radicals were added to organic compounds in search of high proton and deuteron polarizations. Few found practical application. A short review is presented, and special attention is given to some stable nitroxyl radicals which have lately been admixed to organic compounds solid at room temperature, in particular to scintillators.

  15. Free radicals and polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Bunyatova, E.I. E-mail: bunyatel@nusun.jinr.ru

    2004-06-21

    Many free radicals were added to organic compounds in search of high proton and deuteron polarizations. Few found practical application. A short review is presented, and special attention is given to some stable nitroxyl radicals which have lately been admixed to organic compounds solid at room temperature, in particular to scintillators.

  16. Hydroxyl radical reactivity with diethylhydroxylamine

    International Nuclear Information System (INIS)

    Gorse, R.A. Jr.; Lii, R.R.; Saunders, B.B.

    1977-01-01

    Diethylhydroxylamine (DEHA) reacts with gas-phase hydroxyl radicals on every third collision, whereas the corresponding reaction in aqueous solution is considerably slower. The high gas-phase reactivity explains the predicted inhibitory effect of DEHA in atmospheric smog processes. Results from the studies in the aqueous phase are helpful in predicting the mechanism of the reaction of DEHA with hydroxyl radicals

  17. In vitro preparation and assessment of radical reducing peptide from Octopus aegina using digestive proteases.

    Science.gov (United States)

    Sudhakar, Sekar; Nazeer, Rasool Abdul

    2017-07-01

    Antioxidant peptides protect biological macromolecules against radical damages. The use of these peptides was evaluated using free radicals scavenging assays [2,2-diphenyl-1 picrylhydrazyl (DPPH) and hydroxyl] with the help of UV-visible and electron spin resonance (ESR) spectroscopy methods. The Octopus aegina mantle protein were tested upon hydrolysis using gastrointestinal enzymes up to 12 h, where pepsin hydrolysate exhibited superior properties (DPPH: 44.39±0.67% and hydroxyl: 38.84±1.07%) compared with trypsin and α-chymotrypsin. Consequently, the antioxidant activity of the purified hydrolysate increased on a successive purification, and the peptide sequence was determined to be 368.9 Da with Gly-Glu-Tyr amino acids. Tripeptide exerted free radical scavenging efficiency in DNA damage, lipid peroxidation and cellular destruction (MCF7 cells) under stress condition. The results obtained with octopus antioxidant peptide suggested its role as an adjunct in food and pharmaceutical industries. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  19. Calorimetric and spectroscopic properties of small globular proteins (bovine serum albumin, hemoglobin) after free radical generation

    International Nuclear Information System (INIS)

    Farkas, N.; Belagyi, J.; Lorinczy, D.

    2003-01-01

    Mild oxidation of -SH-containing proteins (serum albumin, hemoglobin) by Ce(IV)-ions in the presence of the spin trap phenyl-tert-butylnitrone (PBN) resulted in the appearance of strongly immobilized nitroxide free radicals which evidences the formation of thiyl radicals on the thiol site of the proteins. In hydroxyl free radical generating system a fraction of strongly immobilized nitroxide radicals was also detected in these proteins, which implies that the oxidation of a fraction of the thiol groups was also involved in the free radical reaction. According to the differential scanning calorimetry (DSC) experiments the melting processes of the proteins were calorimetrically irreversible, therefore the two-state kinetic model was used to evaluate the experiments. The results support the view that site-specific interaction of SH-containing proteins with hydroxyl and thiyl free radicals is able to modify the internal dynamics of proteins and affect the conformation of large molecules

  20. Free radical scavenging activity of a novel antioxidative peptide purified from hydrolysate of bullfrog skin, Rana catesbeiana Shaw.

    Science.gov (United States)

    Qian, Zhong-Ji; Jung, Won-Kyo; Kim, Se-Kwon

    2008-04-01

    In the present study, a peptide having antioxidant properties was isolated from bullfrog skin protein, Rana catesbeiana Shaw. Bullfrog skin protein was hydrolyzed using alcalase, neutrase, pepsin, papain, alpha-chymotrypsin and trypsin. Antioxidant activities of respective hydrolysates were evaluated using lipid peroxidation inhibition assay and direct free radical scavenging activity by using electron spin resonance (ESR) spectrometer. Among hydrolysates, alcalase derived hydrolysate exhibited the highest antioxidant activities than those of other enzyme hydrolysates. In order to purity a peptide having potent antioxidant properties, alcalase hydrolysate was separated using consecutive chromatographic methods on a Hiprep 16/10 DEAE FF anion exchange column, Superdex Peptide 10/300 GL gel filtration column and highan octadecylsilane (ODS) C18 reversed phase column. Finally, a potent antioxidative peptide was isolated and its sequence was identified to be LEELEEELEGCE (1487 Da) by Q-TOF ESI mass spectroscopy. This antioxidant peptide from bullfrog skin protein (APBSP) inhibited lipid peroxidation higher than that of alpha-tocopherol as positive control and efficiently quenched different sources of free radicals: DPPH radical (IC(50)=16.1 microM), hydroxyl radical (IC(50)=12.8 microM), superoxide radical (IC(50)=34.0 microM) and peroxyl radical (IC(50)=32.6 microM). Moreover, MTT assay showed that this peptide does not exert any cytotoxicity on human embryonic lung fibroblasts cell line (MRC-5).

  1. On the time behaviour of the concentration of pyrazinium radical cations in the early stage of the Maillard reaction

    Science.gov (United States)

    Stoesser, Reinhard; Klein, Jeannette; Peschke, Simone; Zehl, Andrea; Cämmerer, Bettina; Kroh, Lothar W.

    2007-08-01

    During the early stage of the Maillard reaction pyrazinium radical cations were detected by ESR within the reaction system D-glucose/glycine. The spectra were characterized by completely resolved hyperfine structure. The partial pressure of oxygen and the radical concentrations were measured directly in the reaction mixture by ESR using solutions of the spin probe TEMPOL and of DPPH, respectively. There are quantitative and qualitative relations of the actual concentration of the radical ions to the partial pressure of oxygen, the temperature-time regime and the mechanical mixing of the reaction system. These macroscopic parameters significantly affect both the induction period and the velocity of the time-dependent formation of free radicals. From in situ variations of p(O 2) and p(Ar) including the connected mixing effects caused by the passing the gases through the reaction mixture, steric and chemical effects of the stabilization of the radical ions were established. The determination of suitable and relevant conditions for stabilization and subsequent radical reactions contributes to the elucidation of the macroscopically known antioxidant activity of Maillard products.

  2. Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

    Energy Technology Data Exchange (ETDEWEB)

    Lespade, Laure, E-mail: l.lespade@ism.u-bordeaux1.fr

    2016-08-22

    Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH{sup ·} or ABTS{sup ·+} is explained. - Abstract: Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car–Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

  3. Radical-scavenging-linked antioxidant activities of extracts from black chokeberry and blueberry cultivated in Korea.

    Science.gov (United States)

    Hwang, Seok Joon; Yoon, Won Byong; Lee, Ok-Hwan; Cha, Seung Ju; Kim, Jong Dai

    2014-03-01

    The objective of this study was to investigate the radical-scavenging-linked antioxidant properties of the extracts from black chokeberry and blueberry cultivated in Korea. The 70% ethanol extracts were prepared from black chokeberry and blueberry, and evaluated for total phenolic content, total flavonoid content, total proanthocyanidin content, and antioxidative activities, using various in vitro assays, such as DPPH(2,2-diphenyl-1-picrylhydrazyl), ABTS(2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulphonic acid)) radical-scavenging activity, FRAP(ferric-reducing antioxidant power) and reducing power. The major phenolic compounds, including cyanidin-3-galactoside, cyanidin-3-arabinoside, neochlorogenic acid, procyanidin B1, were analysed by HPLC with a photodiode array detector. Results showed that total phenol, flavonoid and proanthocyanidin contents of black chokeberry extract were higher than those of blueberry extract. In addition, black chokeberry extract exhibited higher free radical-scavenging activity and reducing power than did blueberry extract. Cyanidin-3-galactoside was identified as a major phenolic compound, with considerable content in black chokeberry, that correlated with its higher antioxidant and radical-scavenging effects. These results suggest that black chokeberry extracts could be considered as a good source of natural antioxidants and functional food ingredients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

    International Nuclear Information System (INIS)

    Lespade, Laure

    2016-01-01

    Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH · or ABTS ·+ is explained. - Abstract: Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car–Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

  5. Chemical Constituents with Free-Radical-Scavenging Activities from the Stem of Microcos paniculata

    Directory of Open Access Journals (Sweden)

    Yu Chen

    2010-08-01

    Full Text Available The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate (ABTS and Co (II EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc extract showed the highest free-radical-scavenging activity compared with the other three (n-BuOH, water and petroleum ether extracts. Free-radical-scavenging assay-guided chromatographic separation of the EtOAc extract, using a normal-phase and reverse-phase silica gel column chromatography yielded five compounds: a new triterpene named methyl 3b-O-p-hydroxy-E-cinnamoyloxy-2a,23-dihydroxyolean-12-en-28-oate (1, whose spectral data are presented for the first time, together with four known compounds, epicatechin (2, 3-trans-feruloyl maslinic acid (3, maslinic acid (4 and sucrose (5. All of the compounds were isolated from Microcos paniculata for the first time. The compounds were identified by spectroscopic methods. Among them, compound 2 displayed significant free-radical-scavenging activity which is similar to that of standard antioxidant ascorbic acid (VC and therefore may be a promising natural antioxidant.

  6. Synthesis, Characterization, and Evaluation of Radical Scavenging Ability of Ellagic Acid-Loaded Nanogels

    Directory of Open Access Journals (Sweden)

    Gautam Behl

    2011-01-01

    Full Text Available Ellagic acid (EA, a potential antioxidant phytochemical has low aqueous solubility and bioavailability. In this paper, encapsulation of ellagic acid has been carried out into the biodegradable disulfide crosslinked poly (ethylene glycol PEO-based nanogels synthesized via AGET (activator generated electron transfer ATRP (atom transfer radical polymerization, and their radical scavenging ability was evaluated. The encapsulation of the EA was carried out at two drug loading percentages, that is, 10 and 20 wt.% of the nanogels. 1,1-Diphenyl-2-picryldrazyl (DPPH assay was utilized in order to assess the radical scavenging ability of the ellagic acid-loaded nanogels. A drug-loading level of about 2.5 wt.% was achieved with encapsulation efficiency of about 25% at 10 wt.% of the EA w.r.t nanogels, which was found to increase to about 4.7 wt.% with decreased encapsulation efficiency of 23.5% as EA content was increased to 20wt.% of the nanogels. Ellagic acid loading was found to be accompanied with increase in the size of the nanogels from 144.6±39.52 nm for neat nanogels to 217.8±105.5 and 633±160.1 nm at 2.5 and 4.7 wt.% drug loading level. The nanogels were found to be capable of scavenging radicals and biocompatible on human cervical cancer cell lines (HeLa cells at appropriate concentrations.

  7. Radical production in biological systems

    International Nuclear Information System (INIS)

    Johnson, J.R.; Akabani, G.

    1994-10-01

    This paper describes our effort to develop a metric for radiation exposure that is more fundamental than adsorbed dose and upon which a metric for exposure to chemicals could be based. This metric is based on the production of radicals by the two agents. Radicals produced by radiation in biological systems commonly assumed to be the same as those produced in water despite the presence of a variety of complex molecules. This may explain why the extensive efforts to describe the relationship between energy deposition (track structure) and molecular damage to DNA, based on the spectrum of radicals produced, have not been successful in explaining simple biological effects such as cell killing. Current models assume that DNA and its basic elements are immersed in water-like media and only model the production and diffusion of water-based radicals and their interaction with DNA structures; these models lack the cross sections associated with each macro-component of DNA and only treat water-based radicals. It has been found that such models are not realistic because DNA is not immersed in pure water. A computer code capable of simulating electron tracks, low-energy electrons, energy deposition in small molecules, and radical production and diffusion in water like media has been developed. This code is still in at a primitive stage and development is continuing. It is being used to study radical production by radiation, and radical diffusion and interactions in simple molecular systems following their production. We are extending the code to radical production by chemicals to complement our PBPK modeling efforts. It therefore has been developed primarily for use with radionuclides that are in biological materials, and not for radiation fields

  8. Guest Editorial: Processes of Radicalization and De-Radicalization

    Directory of Open Access Journals (Sweden)

    Donatella Della Porta

    2012-05-01

    Full Text Available The study of radicalization and de-radicalization, understood as processes leading towards the increased or decreased use of political violence, is central to the question of how political violence emerges, how it can be prevented, and how it can be contained. The focus section of this issue of the International Journal of Conflict and Violence addresses radicalization and de-radicalization, seeking to develop a more comprehensive understanding of the processes, dynamics, and mechanisms involved and taking an interdisciplinary approach to overcome the fragmentation into separate disciplines and focus areas. Contributions by Pénélope Larzillière, Felix Heiduk, Bill Kissane, Hank Johnston, Christian Davenport and Cyanne Loyle, Veronique Dudouet, and Lasse Lindekilde address repressive settings, legitimacy, institutional aspects, organizational outcomes, and dynamics in Europe, Asia, Africa, and North and South America.

  9. Reactions of linoleic acid peroxyl radicals with phenolic antioxidants: a pulse radiolysis study

    International Nuclear Information System (INIS)

    Erben-Russ, Michael; Bors, Wolf; Saran, Manfred

    1987-01-01

    Linoleic acid peroxyl radicals (LOO) can be viewed as model intermediates occurring during lipid peroxidation processes. Formation and reactions of these species were investigated in aqueous alkaline solution using pulse radiolysis combined with kinetic spectroscopy. Irradiation of linoleic acid in N 2 O/O 2 -saturated solutions leads to a mixture of peroxyl radical isomers; reaction of 13-hydroperoxylinoleic acid (13-LOOH) with azide radicals in N 2 O-saturated solution produces 13-LOO radicals specifically. These peroxyl radicals cannot be observed directly, but their reactions with kaempferol and quercetin, acting as radical-scavenging antioxidants, produced strongly absorbing aroxyl radicals (ArO). The same aroxyl radicals were generated by OH and N 3 with rate constants exceeding 10 9 dm 3 mol -1 s -1 . Applying a reaction scheme that includes competing generation and decay reactions of both LOO and ArO radicals, individual rate constants were derived for LOO reactions with the phenols (> 10 7 dm 3 mol -1 s-? 1 ), with aroxyl radicals to form covalent adducts (> 10 8 dm 3 mol -1 s -1 ), as well as for their bimilecular decay (3.0 x 10 8 dm 3 mol -1 s -1 ). These results demonstrate high reactivity of fatty acid peroxyl radicals and flavone antioxidants in aqueous solution. (author)

  10. Reactions of linoleic acid peroxyl radicals with phenolic antioxidants: a pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Erben-Russ, M.; Bors, W.; Saran, M.

    1987-09-01

    Linoleic acid peroxyl radicals (LOO) can be viewed as model intermediates occurring during lipid peroxidation processes. Formation and reactions of these species were investigated in aqueous alkaline solution using pulse radiolysis combined with kinetic spectroscopy. Irradiation of linoleic acid in N/sub 2/O/O/sub 2/-saturated solutions leads to a mixture of peroxyl radical isomers; reaction of 13-hydroperoxylinoleic acid (13-LOOH) with azide radicals in N/sub 2/O-saturated solution produces 13-LOO radicals specifically. These peroxyl radicals cannot be observed directly, but their reactions with kaempferol and quercetin, acting as radical-scavenging antioxidants, produced strongly absorbing aroxyl radicals (ArO). The same aroxyl radicals were generated by OH and N/sub 3/ with rate constants exceeding 10/sup 9/ dm/sup 3/ mol/sup -1/ s/sup -1/. Applying a reaction scheme that includes competing generation and decay reactions of both LOO and ArO radicals, individual rate constants were derived for LOO reactions with the phenols (> 10/sup 7/ dm/sup 3/ mol/sup -1/ s-./sup 1/), with aroxyl radicals to form covalent adducts (> 10/sup 8/ dm/sup 3/ mol/sup -1/ s/sup -1/), as well as for their bimilecular decay (3.0 x 10/sup 8/ dm/sup 3/ mol/sup -1/ s/sup -1/). These results demonstrate high reactivity of fatty acid peroxyl radicals and flavone antioxidants in aqueous solution.

  11. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2013-01-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  12. CONTINENT RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    Yu. P. Sernyak

    2014-07-01

    Full Text Available Objective: to evaluate the impact of dissection of the dorsal venous complex without pre-ligation, suturing, or coagulation during radical prostatectomy (RPE in patients with localized prostate cancer (PC on the quality of surgery and the function of urinary retention.Subjects and methods. The data of 42 patients who had undergone posterior and anterior anatomical repair and vesicourethral anastomosis using a V-lock suture after prostatectomy were analyzed. All the patients were divided into 2 groups. Group 1 consisted of 22 patients in whom the dorsal venous complex was closed using a 3-0 vicryl suture before urethral dissection. Group 2 included 20 patients in whom the urethra was dissected without suturing the venous complex.Results. In group 1, complete urinary retention after catheter removal was noted in 9 (40.9 % and 15 (68 % patients within 24 hours and after 3 months, respectively. Following 12 months, two (9 % patients were observed to have partial mild urinary incontinence (as many as 2 pads per day. Group 2 patients showed complete urinary retention in 17 (85 % cases on the first day after catheter removal; all the patients retained urine 3 months later.Conclusion. In patients with localized PC, dissection of the dorsal venous complex without presuturing during laparoscopic RPE exerts a considerable impact on the preservation of urinary retention, namely 45% more of the patients reported complete urinary retention in early periods and 10 % more did this in later periods. At the same time, there was no statistically significant increase in intraoperative blood loss (p > 0.05, the number of positive edges, or biochemical recurrences.

  13. Radical Change: Books for Youth in a Digital Age

    Science.gov (United States)

    Dresang, Eliza T.

    2008-01-01

    "Radical Change: Books for Youth in a Digital Age" (Dresang, 1999) is a landmark work that examines ways in which young readers are affected by the Digital Age. The impetus for the book grew out of Eliza Dresang's observation that printed books with nonlinear, interactive qualities appeal strongly to contemporary children. She noted that…

  14. Redox Properties of Free Radicals.

    Science.gov (United States)

    Neta, P.

    1981-01-01

    Describes pulse radiolysis as a useful means in studing one-electron redox potentials. This method allows the production of radicals and the determination of their concentration and rates of reaction. (CS)

  15. Penile rehabilitation after radical prostatectomy

    DEFF Research Database (Denmark)

    Fode, Mikkel; Ohl, Dana A; Ralph, David

    2013-01-01

    The pathophysiology of erectile dysfunction after radical prostatectomy (RP) is believed to include neuropraxia, which leads to temporarily reduced oxygenation and subsequent structural changes in penile tissue. This results in veno-occlusive dysfunction, therefore, penile rehabilitation programmes...

  16. 8-METHOXYNEORAUTENOL AND RADICAL SCAVENGING ...

    African Journals Online (AJOL)

    Preferred Customer

    8-METHOXYNEORAUTENOL AND RADICAL SCAVENGING FLAVONOIDS FROM. ERYTHRINA ABYSSINICA. Abiy Yenesew1*, Hannington Twinomuhwezi1 ... shown that the plant elaborates alkaloids [1], flavanones, pterocarpans, chalcones and isoflavonoids [1, 3]; some of which have been shown to have antimicrobial ...

  17. Radical Change by Entrepreneurial Design

    National Research Council Canada - National Science Library

    Roberts, Nancy C

    1998-01-01

    .... Radical change by entrepreneurial design then becomes the focal point, in order to acquaint the reader with the strategies and tactics of well-known entrepreneurs who have been successful in molding...

  18. Atmospheric measurements of peroxy radicals by chemical amplification

    Science.gov (United States)

    Duncianu, Marius; Lahib, Ahmad; Tomas, Alexandre; Dusanter, Sébastien

    2017-04-01

    Peroxy radicals (HO2 and RO2) are key species in atmospheric chemistry. They are produced during the oxidation of volatile organic compounds (VOCs) and are involved in the formation of ozone and secondary organic aerosols. However, ambient measurements of these reactive species are still considered challenging and only a few techniques have been used for field measurements. Among these techniques, the PEroxy Radical Chemical Amplifier (PERCA) implementing the classical NO/CO reagent approach has been hardly used for field measurements due to the strong dependence of the radical chain length on Relative Humidity (RH). However, Wood et al. (ES&T 2016) recently showed that using ethane instead of CO allows reducing this RH-dependence and helps going around other drawbacks of the CO based amplification chemistry. This new approach has been explored in our laboratory by building a PERCA instrument that will be used for both laboratory kinetics and field measurements. In this presentation, we will describe (i) the measurement setup and (ii) experiments conducted to quantify the radical chain length for HO2 and several RO2 radicals, including those produced during the OH-oxidation of isoprene, toluene, cyclohexane, and others. It will be shown that the detection efficiency of organic peroxy radicals, via their NO conversion to HO2, mainly depends on their organic nitrate (RONO2) formation yields. In this context, box modelling of the PERCA chemistry will be discussed.

  19. Ecoporn, Irrationalities and Radical Environmentalism

    OpenAIRE

    Măntescu, Liviu

    2016-01-01

    This study explores the ‘irrationalities’ of deep ecology activism in the context of radical environmentalism by using the empirical example of ecoporn. Fuck For Forest is an environmental Non-Governmental Organisation which undertakes fund-raising for re-forestation and forest protection by means of pornography. Following twelve months of ethnographic fieldwork, this study presents first research results on a radical environmental project which does not promote democratic and established pro...

  20. [Urine derivation after radical cystectomy].

    Science.gov (United States)

    Jarabák, J; Zachoval, R; Vik, V

    2014-01-01

    Radical cystectomy, performed both for the treatment of cancer and other conditions, needs to be followed by ensuring the derivation of urine. The aim of this work is to summarize the possibilities of urine derivation after cystectomy, their advantages, disadvantages and long-term results. A review article summarising relevant literature and the team of authors own experience. This work compares advantages and risks of different types of urine derivation following radical cystectomy.

  1. Cranberry flavonoids prevent toxic rat liver mitochondrial damage in vivo and scavenge free radicals in vitro.

    Science.gov (United States)

    Lapshina, Elena A; Zamaraeva, Maria; Cheshchevik, Vitali T; Olchowik-Grabarek, Ewa; Sekowski, Szymon; Zukowska, Izabela; Golovach, Nina G; Burd, Vasili N; Zavodnik, Ilya B

    2015-06-01

    The present study was undertaken for further elucidation of the mechanisms of flavonoid biological activity, focusing on the antioxidative and protective effects of cranberry flavonoids in free radical-generating systems and those on mitochondrial ultrastructure during carbon tetrachloride-induced rat intoxication. Treatment of rats with cranberry flavonoids (7 mg/kg) during chronic carbon tetrachloride-induced intoxication led to prevention of mitochondrial damage, including fragmentation, rupture and local loss of the outer mitochondrial membrane. In radical-generating systems, cranberry flavonoids effectively scavenged nitric oxide (IC50  = 4.4 ± 0.4 µg/ml), superoxide anion radicals (IC50  = 2.8 ± 0.3 µg/ml) and hydroxyl radicals (IC50  = 53 ± 4 µg/ml). The IC50 for reduction of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) was 2.2 ± 0.3 µg/ml. Flavonoids prevented to some extent lipid peroxidation in liposomal membranes and glutathione oxidation in erythrocytes treated with UV irradiation or organic hydroperoxides as well as decreased the rigidity of the outer leaflet of the liposomal membranes. The hepatoprotective potential of cranberry flavonoids could be due to specific prevention of rat liver mitochondrial damage. The mitochondria-addressed effects of flavonoids might be related both to radical-scavenging properties and modulation of various mitochondrial events. Copyright © 2015 John Wiley & Sons, Ltd.

  2. Evaluation of free radical scavenging activity of tea infusion of commercial tea products available in uae

    International Nuclear Information System (INIS)

    Nessa, F.; Khan, S.A.

    2014-01-01

    In the present study, twenty four commercial tea samples were assayed to determine their free radical scavenging activity and polyphenolic contents based on the brewing/infusing period. Tea samples were infused/brewed in 200 mL boiled water at 120 degree C for 1, 2 and 5 min, respectively. The radical scavenging activities of tea infusion/brewing were measured using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) assay method. The results were ranged from 67.81-90.51% for black tea bags, 90.37-94.51% for green tea bags, 24.66-92.25% for black tea powder, 16.08-93.06% for green tea powder and 32.90- 45.54% for Camomile herbal infusion. The results showed that 1 or 2 min black tea bags infusion exhibited highest radical scavenging activity than 5 min infusion. Antioxidant activities of tea powders were variable with the amount of tea powder. It was observed that antioxidant activity increased with increasing boiling time for smaller amount of sample. In contrary, shorter boiling time was better for larger amount of sample. The polyphenol contents of tea infusion were determined and the results were expressed as milligram quercetin equivalent/200 mL of tea infusion. The polyphenol content was increased with increased brewing period. In contrary, brewing for longer time rendered extract less antiradical activity. This study suggests that infusing tea bag for 1 or 2 min is sufficient for getting infusion with maximum radical scavenging activity and in case of tea powder, shorter boiling time is better for larger amount of powder or small amount of powder should be boiled for minimum 5 min for rendering extract with maximum radical scavenging activity. (author)

  3. Phytochemical Analysis and Free Radical Scavenging Activity of Medicinal Plants Gnidia glauca and Dioscorea bulbifera

    Science.gov (United States)

    Ghosh, Sougata; Derle, Abhishek; Ahire, Mehul; More, Piyush; Jagtap, Soham; Phadatare, Suvarna D.; Patil, Ajay B.; Jabgunde, Amit M.; Sharma, Geeta K.; Shinde, Vaishali S.; Pardesi, Karishma; Dhavale, Dilip D.; Chopade, Balu A.

    2013-01-01

    Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS•+ and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS•+ radical with a second order rate constant of 2.33×106 and 1.72×106, respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48×106 and 4.46×106 were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C27H42O3) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important medicinal plants. PMID:24367520

  4. ANTIOXIDANT ACTIVITY OF ETHANOLIC EXTRACT AND FRACTION OF SALAK FRUIT SEEDS ( Salacca zalacca (Gaertn. Voss. USING DPPH (2,2-diphenyl-1-picrylhydrazyl METHOD

    Directory of Open Access Journals (Sweden)

    Sista Werdyani

    2017-09-01

    Full Text Available Salak seeds have been developed as a beverage, but there was still a little amount of research that focused on salak seeds. This research was conducted to find out the chemical compounds and the antioxidant activity of ethanolic extract and fraction of salak fruits seeds ( Salacca zalacca (Gaertn. Voss. which have been grown extensively in Sleman Yogyakarta. Extraction was conducted using maceration, followed by fractionation using vacuum liquid chromatography. The identification of the chemical compounds contained in the ethanolic extract and fraction was performed by thin layer chromatography method, while the antioxidant activity was performed by DPPH method. Comparison of antioxidant activity was seen using IC50 values. The results showed that ethanol extract and fraction contained phenol, flavonoid, and tannin. The largest antioxidant activity was found in F7 with an IC50 value of 110.16 μg / ml.

  5. On polynomial and multiplicative radicals | Tumurbat | Quaestiones ...

    African Journals Online (AJOL)

    We show that polynomial and multiplicative radicals in [1] are special cases of radicals defined by means of elements. We scrutinize the way of defining a radical γG by a subset G of polynomials in noncommuting indeterminates. Defining polynomial radicals, Drazin and Roberts [1] required that the set G be closed

  6. Catalyzed Radical Termination in the Presence of Tellanyl Radicals.

    Science.gov (United States)

    Ribelli, Thomas G; Rahaman, S M Wahidur; Matyjaszewski, Krzysztof; Poli, Rinaldo

    2017-10-09

    The decomposition of the diazo initiator dimethyl 2,2'-azobis(isobutyrate) (V-601), generating the Me 2 C . (CO 2 Me) radical, affords essentially the same fraction of disproportionation and combination in media with a large range of viscosity (C 6 D 6 , [D 6 ]DMSO, and PEG 200) in the 25-100 °C range. This is in stark contrast to recent results by Yamago et al. on the same radical generated from Me 2 C(TeMe)(CO 2 Me) and on other X-TeR systems (X=polymer chain or unimer model; R=Me, Ph). The discrepancy is rationalized on the basis of an unprecedented RTe . -catalyzed radical disproportionation, with support from DFT calculations and photochemicaL V-601 decomposition in the presence of Te 2 Ph 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  8. Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

    Science.gov (United States)

    Camarena-Tello, Julio César; Martínez-Flores, Héctor Eduardo; Garnica-Romo, Ma Guadalupe; Padilla-Ramírez, José Saúl; Saavedra-Molina, Alfredo; Alvarez-Cortes, Osvaldo; Bartolomé-Camacho, María Carmen; Rodiles-López, José Octavio

    2018-02-27

    Guava leaf ( Psidium guajava L.) extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL) in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties.

  9. Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

    Science.gov (United States)

    Martínez-Flores, Héctor Eduardo; Garnica-Romo, Ma. Guadalupe; Padilla-Ramírez, José Saúl; Saavedra-Molina, Alfredo; Alvarez-Cortes, Osvaldo; Bartolomé-Camacho, María Carmen; Rodiles-López, José Octavio

    2018-01-01

    Guava leaf (Psidium guajava L.) extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL) in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties. PMID:29495514

  10. Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity

    Directory of Open Access Journals (Sweden)

    Qing Li

    2018-03-01

    Full Text Available Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating “click reaction” with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC50 < 0.01 mg mL−1 was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains.

  11. Quantification of Phenolic Compounds and In Vitro Radical Scavenging Abilities with Leaf Extracts from Two Varieties of Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Julio César Camarena-Tello

    2018-02-01

    Full Text Available Guava leaf (Psidium guajava L. extracts are used in both traditional medicine and the pharmaceutical industry. The antioxidant compounds in P. guajava leaves can have positive effects including anti-inflammatory, anti-hyperglycemic, hepatoprotective, analgesic, anti-cancer effects, as well as protecting against cardiovascular diseases. In the present study, phenolic compounds and in vitro antioxidant capacity were measured in extracts obtained with polar and non-polar solvents from leaves of two varieties of guava, Calvillo Siglo XXI and Hidrozac. The quantity of total phenolics and total flavonoids were expressed as equivalents of gallic acid and quercetin, respectively. Hydroxyl radical, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS, 2,2-diphenyl-1-picrylhydrazyl (DPPH, and Oxygen Radical Absorbance Capacity using fluorescein (ORAC-FL in vitro tests were used to assess the radical scavenging abilities of the extracts. The total phenolics were higher in the aqueous fraction of the variety Calvillo Siglo XXI, while in the Hidrozac variety total phenolics were higher in the acetone and chloroform fractions. Total flavonoids were higher in all fractions in the variety Calvillo Siglo XXI. Total phenolics showed a highly positive correlation for ORAC-FL, and a moderately positive correlation with hydroxyl radicals. Finally, total flavonoids showed a slightly positive correlation for ORAC-FL and hydroxyl radicals. Both varieties of guava leaf extract showed excellent antioxidant properties.

  12. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  13. Conversion of alkyl radicals to allyl radicals in irradiated single crystal mats of polyethylene

    International Nuclear Information System (INIS)

    Fujimura, T.; Hayakawa, N.; Kuriyama, I.

    1978-01-01

    The decay of alkyl radicals, the conversion of alkyl radicals to allyl radicals and the trapping of allyl radicals in irradiated single crystal mats of polyethylene have been studied by electron spin resonance (e.s.r.). It has been suggested that in the crystal core alkyl radicals react with trans-vinylene double bonds and are converted into trans-vinylene allyl radicals; at the crystal surface, alkyl radicals react with vinyl end groups and are converted into allyl radicals with vinyl end groups. The decay of radical pairs and the formation of trans-vinylene double bonds are discussed. (author)

  14. EVALUATION OF FREEZE DRIED ALOE VERA AND NOPAL CACTUS FOR POSSIBLE HEALTH TREATMENTS BY COMPARISON OF ANTIOXIDANT PROPERTIES AND FREE RADICAL INHIBITION.

    Science.gov (United States)

    Rodriguez, Kenneth R; Jones, Anthony E; Belmont, Barbara

    2014-01-01

    The goal of this project was to characterize the antioxidant powers of lyophilized Aloe Vera ( Aloe barbadensis ) and Nopal Cactus (Opuntia ficus-indica) by quantifying the phenolics content and radical scavenging abilities of preparations derived from these plants. Extracts of these lyophylized succulents were assayed for phenolic compounds by the Folin Ciocalteau method and compared for free radical scavenging capability by the DPPH method. We found that even though the Aloe lyophilizate extract contained more phenolic content, the Nopal lyophilizate exhibited better free radical scavenging ability. Aloe Vera extract contained 0.278 g/L of phenolic content and exhibited 11.1% free radical inhibition, with a free radical scavenging rate constant of 0.177±0.015 min -1 . Nopal Cactus extract contained 0.174 g/L of phenolic content and exhibited 13.2% free radical inhibition, with a free radical scavenging rate constant of 0.155±0.009 min -1 . These results showed Nopal to have greater antioxidant potency than Aloe.

  15. Determination of Radical Scavenging Activity and Total Phenols of Wine and Spices: A Randomized Study

    Directory of Open Access Journals (Sweden)

    Fulgentius Nelson Lugemwa

    2013-07-01

    Full Text Available Thirty eight bottles of red wine (Carbanet Sauvignon were randomly selected based on vintage, region, price, and age (number of months in a barrel. The total phenolic content of each wine was determined using Folin-Ciocalteau assay. The radical scavenging activity was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH assay. Apart from a few bottles that exhibited above average radical scavenging activity and phenolic content, there was no good correlation of those two quantities with region, price or vintage. The average phenolic amount was 2874 mg/L. The lowest phenolic content was found to be 1648 mg/L for an eight dollar wine. Wine with the highest amount of phenol of 4495 mg/L was a 2007, nine dollar bottle from South America. High amount of phenols did not translate into high radical scavenging activity. Barrel-aging did not increase the amount of phenols or the radical scavenging activity of wine. In order to discover new and potent sources of antioxidants from plants, the following spices were studied: ginger, cilantro, cumin, anise, linden, eucalyptus, marjoram, oregano, sage, thyme and rosemary. Whole spices were crushed and extracted for 96 h at room temperature using a combination of ethyl acetate, ethyl alcohol and water in the ratio of 4.5:4.5:1 (v/v/v. The radical scavenging activity of extracts was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH assay. The total phenolic content of each spice was also determined using the Folin-Ciocalteau assay. Eucalyptus was found to be the most potent antioxidant with an LC50 of 324.1 mg of phenol/L, followed by marjoram with an LC50 of 407.5 mg of phenol/L, and rosemary with an LC50 of 414.0 mg/L. The least potent antioxidants were ginger and cilantro with LC50 of 7604 mg/L of phenol and 7876 mg of phenol/L, respectively.

  16. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  17. Laparoscopic radical prostatectomy: a review

    Directory of Open Access Journals (Sweden)

    Pierluigi Bove

    2009-04-01

    Full Text Available INTRODUCTION: We offer an overview of the intra-, peri- and postoperative outcomes of laparoscopic radical prostatectomy (LRP with the endpoint to evaluate potential advantages of this approach. MATERIAL AND METHODS: We conducted an extensive Medline literature search (search terms “laparoscopic radical prostatectomy” and “radical prostatectomy” from 1990 until 2007. Only full-length English language articles identified during this search were considered for this analysis. A preference was given to the articles with large series with more than 100 patients. All pertinent articles concerning localized prostate cancer were reviewed. CONCLUSION:Pure LRP has shown to be feasible and reproducible but it is difficult to learn. Potential advantages over open surgery have to be confirmed by longer-term follow-up and adequately designed clinical studies.

  18. Epistemological barriers to radical behaviorism

    Science.gov (United States)

    O'Donohue, William T.; Callaghan, Glenn M.; Ruckstuhl, L. E.

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers. PMID:22478314

  19. In-vitro free radical scavenging activity of biosynthesized gold and silver nanoparticles using Prunus armeniaca (apricot) fruit extract

    Science.gov (United States)

    Dauthal, Preeti; Mukhopadhyay, Mausumi

    2013-01-01

    In-vitro free radical scavenging activity of biosynthesized gold (Au-NPs) and silver (Ag-NPs) nanoparticles was investigated in the present study. Natural precursor Prunus armeniaca (apricot) fruit extract was used as a reducing agent for the nanoparticle synthesis. The free radical scavenging activity of the nanoparticles were observed by modified 1,1'-diphynyl-2-picrylhydrazyl, DPPH and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS assay. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy, and fourier transform infrared spectroscopy (FTIR). Appearance of optical absorption peak at 537 nm (2.20 keV) and 435 nm (3 keV) within 0.08 and 0.5 h of reaction time was confirmed the presence of metallic Au and Ag nanoclusters, respectively. Nearly spherical nanoparticles with majority of particle below 20 nm (TEM) for both Au-NPs and Ag-NPs were synthesized. XRD pattern confirmed the existence of pure nanocrystalline Au-NPs while few additional peaks in the vicinity of fcc silver-speculated crystallization of metalloproteins of fruit extract on the surface of the Ag-NPs and vice versa. FTIR spectra was supported the role of amino acids of protein/enzymes of fruit extract for synthesis and stabilization of nanoparticles. Dose-dependent scavenging activity was observed for Au-NPs and Ag-NPs in both DPPH and ABTS in-vitro assay. 50 % scavenging activity for DPPH were 11.27 and 16.18 mg and for ABTS 3.40 and 7.12 mg with Au-NPs and Ag-NPs, respectively.

  20. In-vitro free radical scavenging activity of biosynthesized gold and silver nanoparticles using Prunus armeniaca (apricot) fruit extract

    Energy Technology Data Exchange (ETDEWEB)

    Dauthal, Preeti; Mukhopadhyay, Mausumi, E-mail: mausumi_mukhopadhyay@yahoo.com [S.V. National Institute of Technology, Department of Chemical Engineering (India)

    2013-01-15

    In-vitro free radical scavenging activity of biosynthesized gold (Au-NPs) and silver (Ag-NPs) nanoparticles was investigated in the present study. Natural precursor Prunus armeniaca (apricot) fruit extract was used as a reducing agent for the nanoparticle synthesis. The free radical scavenging activity of the nanoparticles were observed by modified 1,1 Prime -diphynyl-2-picrylhydrazyl, DPPH and 2,2 Prime -azinobis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS assay. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy, and fourier transform infrared spectroscopy (FTIR). Appearance of optical absorption peak at 537 nm (2.20 keV) and 435 nm (3 keV) within 0.08 and 0.5 h of reaction time was confirmed the presence of metallic Au and Ag nanoclusters, respectively. Nearly spherical nanoparticles with majority of particle below 20 nm (TEM) for both Au-NPs and Ag-NPs were synthesized. XRD pattern confirmed the existence of pure nanocrystalline Au-NPs while few additional peaks in the vicinity of fcc silver-speculated crystallization of metalloproteins of fruit extract on the surface of the Ag-NPs and vice versa. FTIR spectra was supported the role of amino acids of protein/enzymes of fruit extract for synthesis and stabilization of nanoparticles. Dose-dependent scavenging activity was observed for Au-NPs and Ag-NPs in both DPPH and ABTS in-vitro assay. 50 % scavenging activity for DPPH were 11.27 and 16.18 mg and for ABTS 3.40 and 7.12 mg with Au-NPs and Ag-NPs, respectively.

  1. Disarming Youth Combatants: Mitigating Youth Radicalization and Violent Extremism

    Directory of Open Access Journals (Sweden)

    Alpaslan Özerdem

    2011-01-01

    Full Text Available In the complex of motivating variables that define the push and pull factors behind recruitment and participation in civil conflict, "radicalization"—or "violent extremism"—is not conceived as a very strong motive, as is the case with studies on terrorism. As part of disarming youth combatants,the linkages between reintegration outcomes and possible rerecruitment into radical and extremist violence must be better understood to mitigate such risks. In our analysis, the policies guiding reintegration of child soldiers and youth should be better attuned to the relationship between recruitment motivations and reintegration outcomes, and must be approached from a political lens rather than a purely technical one. The risk of radicalization and involvement in violent extremism is ultimately a structural challenge, which needs to address root causes of recruitment rather than trying to find a solution through a band-aid approach of stopgap reintegration assistance.

  2. Formation of Chlorotriophenoxy Radicals from Complete Series Reactions of Chlorotriophenols with H and OH Radicals

    Directory of Open Access Journals (Sweden)

    Fei Xu

    2015-08-01

    Full Text Available The chlorothiophenoxy radicals (CTPRs are key intermediate species in the formation of polychlorinated dibenzothiophenes/thianthrenes (PCDT/TAs. In this work, the formation of CTPRs from the complete series reactions of 19 chlorothiophenol (CTP congeners with H and OH radicals were investigated theoretically by using the density functional theory (DFT method. The profiles of the potential energy surface were constructed at the MPWB1K/6-311+G(3df,2p//MPWB1K/6-31+G(d,p level. The rate constants were evaluated by the canonical variational transition-state (CVT theory with the small curvature tunneling (SCT contribution at 600–1200 K. The present study indicates that the structural parameters, thermal data, and rate constants as well as the formation potential of CTPRs from CTPs are strongly dominated by the chlorine substitution at the ortho-position of CTPs. Comparison with the study of formation of chlorophenoxy radicals (CPRs from chlorophenols (CPs clearly shows that the thiophenoxyl-hydrogen abstraction from CTPs by H is more efficient than the phenoxyl-hydrogen abstraction from CPs by H, whereas the thiophenoxyl-hydrogen abstraction from CTPs by OH is less impactful than the phenoxyl-hydrogen abstraction from CPs by OH. Reactions of CTPs with H can occur more readily than that of CTPs with OH, which is opposite to the reactivity comparison of CPs with H and OH.

  3. Radical scavenging and antimicrobial activity of essential oil and extracts of Echinophora sibthorpiana Guss. from Macedonia

    Directory of Open Access Journals (Sweden)

    Mileski Ksenija

    2014-01-01

    Full Text Available This study was undertaken to determine the antioxidant and antimicrobial effect of essential oil and extracts of Echinophora sibthorpiana Guss. (fam. Apiaceae collected in Macedonia. The chemical composition of E. sibthorpiana essential oil was characterized by the presence of methyl eugenol (60.40%, p-cymene (11.18% and α-phellandrene (10.23%. The free radical scavenging activity of extracts and essential oil was evaluated by DPPH and ABTS assays. The aqueous extract of aerial parts exhibited the strongest scavenging activity (IC50=1.67 mg/ml; results of the ABTS test showed that the most effective was the ethanol extract of aerial parts (1.11 mg vit. C/g. The essential oil showed stronger antioxidant activity compared to hydroxyanisole, ascorbic acid and quercetin that were used in the DPPH and ABTS tests, respectively. The total phenolic and flavonoid concentrations in the extracts ranged between 38.65-60.72 mg GA/g, and 3.15-19.00 mg Qu/g, respectively. The antimicrobial properties of the extracts and essential oil were investigated using a micro-well dilution technique against human pathogenic strains. The results were comparable with the effects of the positive controls, streptomycin and fluconazole. These findings indicate that E. sibthorpiana extracts and oil can be used in preventive treatments and as an alternative for synthetic preservatives. [Projekat Ministarstva nauke Republike Srbije, br. 173029 i br. 173021

  4. Solvent optimization extraction of antioxidants from foxtail millet species' insoluble fibers and their free radical scavenging properties.

    Science.gov (United States)

    Bangoura, Mohamed Lamine; Nsor-Atindana, John; Ming, Zhou Hui

    2013-11-15

    In this study, water and 80% of four organic solvents were employed to optimize the extraction of antioxidants from two species of foxtail millet's insoluble fibers under the same temperature, time, and solid/solvent ratio. The results showed that the acetone was able to extract the maximum amount of antioxidants (2.32 mg/g fiber for white specie and 3.86 mg/g fiber for yellow specie) followed by methanol and propanol from both samples. The neutral and the ethanol on the other hand extracted small amount of the antioxidants from the two fiber materials. While considerable level of Total Polyphenols Content (TPC) was recorded in both the water and the organic solvents' extracts, only traces of Total Flavonoid content (TFC) were observed in water, methanol and ethanol extracts. Propanol and acetone extracts was negative to the TFC test. The potency of both white and yellow foxtail millets' insoluble fibers antioxidant extracts was investigated using five different in vitro tests. It was realized that there was a variation in their capacities to quench DPPH and ABTS(+) radicals for the time running of 0-60 min. The samples from the yellow cereal exhibited high inhibition capacity against ABTS(+). No correlation was observed between TPC and radical scavenging capacities for DPPH and ABTS(+). In general, the yellow species contained more antioxidants in comparison with the white one and this accounted for its high antioxidant activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Essential Oil from Flowers and Leaves of Elaeagnus Angustifolia (Elaeagnaceae): Composition, Radical Scavenging and General Toxicity Activities.

    Science.gov (United States)

    Torbati, Mohammadali; Asnaashari, Solmaz; Heshmati Afshar, Fariba

    2016-06-01

    The aim of this work was to identify the chemical composition of the essential oils obtained from the flowers and leaves of Elaeagnus angostifolia (Elaeagnaceae) along with evaluate the radical scavenging and general toxicity activities. A combination of GC-MS and GC-FID were utilized for analyzing the chemical profile of the essential oils extracted by hydro-distillation from the leaves and flowers of E. angustifolia. The essential oils were subjected to general toxicity and radical scavenging assays using brine shrimp lethality test and DPPH method, respectively. In total, 53 and 25 components were identified and quantified in the essential oils of flowers and leaves, accounting for 96.59% and 98.97% of the oil, respectively. The both oils were observed to be rich in ester compounds. The most abundant components of the oil from flowers were E-ethyl cinnamate (60.00%), hexahydrofarnesyl acetone (9.99%), palmitic acid (5.20%) and phytol (3.29%). The major constituents of the oil from leaves were E-ethyl cinnamate (37.27%), phytol (12.08%), nonanal (10.74%) and Z-3-hexenyl benzoate (7.65%). Both oils showed moderate activity in DPPH assay; however, they exhibited potent tocixity in brine shrimp lethality test. The remarkable toxicity effects of the oils are worthy to further investigation to find the probable mechanisms of action accountable for the noticeable toxic effect of these essential oils.

  6. Thermal Behavior and Free-Radical-Scavenging Activity of Phytic Acid Alone and Incorporated in Cosmetic Emulsions

    Directory of Open Access Journals (Sweden)

    André Luis Máximo Daneluti

    2015-07-01

    Full Text Available Phytic acid is a natural compound widely used as depigmenting agent in cosmetic emulsions. Few studies are available in the literature covering the stability and the antioxidating property of this substance, used alone or into emulsions. Therefore, the purpose of this work was to investigate the thermal behavior and antioxidant properties of phytic acid alone and into cosmetic emulsions. The thermal behavior of this substance was evaluated by thermogravimetry (TG/derivative thermogravimetry (DTG and differential scanning calorimetry (DSC and the free-radical-scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH. TG/DTG and DSC curves allowed evaluation of the thermal behavior of phytic acid. These results showed that the substance presented four stages of mass loss. Thermal decomposition of the material initiated at 150 °C. Thermal behavior of the cosmetic emulsions detected that the addition of phytic acid decreased the thermal stability of the system. DPPH free-radical-scavenging activity showed that phytic acid incorporated into emulsion had no antioxidant capacity compared to BHT. In summary, we concluded that the thermoanalytical techniques (TG and DSC were efficient and reliable in the characterization of phytic acid alone and incorporated into cosmetic emulsions.

  7. Radical democratic politics and feminism

    Directory of Open Access Journals (Sweden)

    Martínez Labrin, Soledad

    2006-05-01

    Full Text Available In the article I present a reflection around the radical democratic project proposed by Chantal Mouffe and Ernesto Laclau. Specifically, I examine the application of the project in the context of the “new social movements” and especially, of feminist movement. I state the need of drawing attention to universalism and essentialism as the main obstacles to generate a collective proposal without margins. Nevertheless, doubts remind about the possibility of building up a feminism tailored by the radical democratic project, in a stage in which the political action of such a movement is characterized by categories that are closed and crystallized

  8. Assessment of Free Radical Scavenging Potential and Oxidative DNA Damage Preventive Activity of Trachyspermum ammi L. (Carom and Foeniculum vulgare Mill. (Fennel Seed Extracts

    Directory of Open Access Journals (Sweden)

    Nandini Goswami

    2014-01-01

    Full Text Available Oxidation of biomolecules such as carbohydrates, proteins, lipids, and nucleic acids results in generation of free radicals in an organism which is the major cause of onset of various degenerative diseases. Antioxidants scavenge these free radicals, thereby protecting the cell from damage. The present study was designed to examine the free radical scavenging potential and oxidative DNA damage preventive activity of traditionally used spices Trachyspermum ammi L. (carom and Foeniculum vulgare Mill. (fennel. The aqueous, methanolic, and acetonic extracts of T. ammi and F. vulgare seeds were prepared using soxhlet extraction assembly and subjected to qualitative and quantitative estimation of phytochemical constituents. Free radical scavenging potential was investigated using standard methods, namely, DPPH radical scavenging assay and ferric reducing antioxidant power assay along with the protection against oxidative DNA damage. The results stated that acetonic seed extracts (AAcSE and FAcSE of both the spices possessed comparatively high amount of total phenolics whereas methanolic seed extracts (AMSE and FMSE were found to have highest amount of total flavonoids. At 1 mg/mL concentration, highest DPPH radical scavenging activity was shown by FMSE (96.2%, AAcSE was recorded with highest FRAP value (2270.27 ± 0.005 μmol/L, and all the seed extracts have been shown to mitigate the damage induced by Fenton reaction on calf thymus DNA. Therefore, the study suggests that T. ammi and F. vulgare seed extracts could contribute as a highly significant bioresource of antioxidants to be used in our day-to-day life and in food and pharmaceutical industry.

  9. Assessment of free radical scavenging potential and oxidative DNA damage preventive activity of Trachyspermum ammi L. (carom) and Foeniculum vulgare Mill. (fennel) seed extracts.

    Science.gov (United States)

    Goswami, Nandini; Chatterjee, Sreemoyee

    2014-01-01

    Oxidation of biomolecules such as carbohydrates, proteins, lipids, and nucleic acids results in generation of free radicals in an organism which is the major cause of onset of various degenerative diseases. Antioxidants scavenge these free radicals, thereby protecting the cell from damage. The present study was designed to examine the free radical scavenging potential and oxidative DNA damage preventive activity of traditionally used spices Trachyspermum ammi L. (carom) and Foeniculum vulgare Mill. (fennel). The aqueous, methanolic, and acetonic extracts of T. ammi and F. vulgare seeds were prepared using soxhlet extraction assembly and subjected to qualitative and quantitative estimation of phytochemical constituents. Free radical scavenging potential was investigated using standard methods, namely, DPPH radical scavenging assay and ferric reducing antioxidant power assay along with the protection against oxidative DNA damage. The results stated that acetonic seed extracts (AAcSE and FAcSE) of both the spices possessed comparatively high amount of total phenolics whereas methanolic seed extracts (AMSE and FMSE) were found to have highest amount of total flavonoids. At 1 mg/mL concentration, highest DPPH radical scavenging activity was shown by FMSE (96.2%), AAcSE was recorded with highest FRAP value (2270.27 ± 0.005 μmol/L), and all the seed extracts have been shown to mitigate the damage induced by Fenton reaction on calf thymus DNA. Therefore, the study suggests that T. ammi and F. vulgare seed extracts could contribute as a highly significant bioresource of antioxidants to be used in our day-to-day life and in food and pharmaceutical industry.

  10. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  11. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  12. Missing Peroxy Radical Sources Within a Rural Forest Canopy

    Science.gov (United States)

    Wolfe, G. M.; Cantrell, C.; Kim, S.; Mauldin, R. L., III; Karl, T.; Harley, P.; Turnipseed, A.; Zheng, W.; Flocke, F.; Apel, E. C.; hide

    2013-01-01

    Organic peroxy (RO2) and hydroperoxy (HO2) radicals are key intermediates in the photochemical processes that generate ozone, secondary organic aerosol and reactive nitrogen reservoirs throughout the troposphere. In regions with ample biogenic hydrocarbons, the richness and complexity of peroxy radical chemistry presents a significant challenge to current-generation models, especially given the scarcity of measurements in such environments. We present peroxy radical observations acquired within a Ponderosa pine forest during the summer 2010 Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen - Rocky Mountain Organic Carbon Study (BEACHON-ROCS). Total peroxy radical mixing ratios reach as high as 180 pptv and are among the highest yet recorded. Using the comprehensive measurement suite to constrain a near-explicit 0-D box model, we investigate the sources, sinks and distribution of peroxy radicals below the forest canopy. The base chemical mechanism underestimates total peroxy radicals by as much as a factor of 3. Since primary reaction partners for peroxy radicals are either measured (NO) or under-predicted (HO2 and RO2, i.e. self-reaction), missing sources are the most likely explanation for this result. A close comparison of model output with observations reveals at least two distinct source signatures. The first missing source, characterized by a sharp midday maximum and a strong dependence on solar radiation, is consistent with photolytic production of HO2. The diel profile of the second missing source peaks in the afternoon and suggests a process that generates RO2 independently of sun-driven photochemistry, such as ozonolysis of reactive hydrocarbons. The maximum magnitudes of these missing sources (approximately 120 and 50 pptv min-1, respectively) are consistent with previous observations alluding to unexpectedly intense oxidation within forests. We conclude that a similar mechanism may underlie many such observations.

  13. Preparation of Egg White Liquid Hydrolysate (ELH) and Its Radical-Scavenging Activity.

    Science.gov (United States)

    Noh, Dong Ouk; Suh, Hyung Joo

    2015-09-01

    In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of α-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of α-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and α-amino nitrogen content after 24 h-hydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (Pegg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products.

  14. Selenium and Zinc content and radical scavenging capacity of edible mushrooms Armilaria mellea and Lycoperdon saccatum

    Directory of Open Access Journals (Sweden)

    Z. Zeković

    2010-01-01

    Full Text Available Armillaria mellea and Lycoperdon saccatum are two delicious mushrooms growing widely trough all Balkan region. Investigation of A. mellea and L. saccatum antioxidant properties includes preparation of mushrooms extracts, determination of Selenium and Zinc content and evaluation of theirs antioxidant activity involving scavenging activity of ˙O2- radicals, DPPH and reducing power assay. Higher extraction yield of 24.48 % has been achieved for L. saccatum, but higher content of Selenium and Zinc was determined in A. mallea extract, 2.359 mg/kg and 50.380 mg/kg, respectively. The radical scavenging activity was found to exhibit 50 % of inhibition value (IC50 value at the extracts concentration of 0.0161±0.0001 mg/ml for the L. saccatum extract and 0.0108±0.0002 mg/ml for A. mallea extract. The determined relative inhibition of ˙O2- radicals for L. sacatum extract is lower than for A. malea. It was determined that both mushrooms extract posses’ reductive capabilities and thus were capable of reducing iron (III.

  15. Threshold photoelectron spectroscopy of the imidogen radical

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Gustavo A., E-mail: gustavo.garcia@synchrotron-soleil.fr [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Gans, Bérenger [Institut des Sciences Moléculaires d’Orsay, Univ Paris-Sud, CNRS, Bât 210, Univ Paris-Sud, 91405 Orsay Cedex (France); Tang, Xiaofeng [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Ward, Michael; Batut, Sébastien [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Nahon, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Fittschen, Christa [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Loison, Jean-Christophe [ISM, Université de Bordeaux, CNRS, 351 cours de la Libération, 33405 Talence Cedex (France)

    2015-08-15

    We present the threshold photoelectron spectroscopy of the imidogen radical (NH) recorded in the photon energy region up to 1 eV above its first ionization threshold. The radical was produced by reaction of NH{sub 3} and F in a microwave discharge flow-tube and photoionized using vacuum ultraviolet (VUV) synchrotron radiation. A double imaging coincidence spectrometer was used to record mass-selected spectra and avoid contributions from the byproducts present in the reactor and background gas. The energy region includes the ground X{sup +2}Π and first electronically excited a{sup +4}Σ{sup −} states of NH{sup +}. Strong adiabatic transitions and weak vibrational progressions up to v{sup +} = 2 are observed for both electronic states. The rotational profile seen in the origin band has been modeled using existing neutral and cationic spectroscopic constants leading to a precise determination of the adiabatic ionization energy at 13.480 ± 0.002 eV.

  16. Propargyl radical chemistry: renaissance instigated by metal coordination.

    Science.gov (United States)

    Melikyan, Gagik G

    2015-04-21

    Over the last two decades, radical chemistry of propargyl systems was developed into a potent synthetic field providing access to classes of organic compounds that are otherwise hardly accessible. The levels of diastereoselection thus achieved (up to 100%) are unprecedented for free propargyl radicals, as well as for organic radicals π-bonded to transition metals. These advances were enabled by the coordination of the triple bond to a Co2(CO)6 core that precluded an acetylene-allene rearrangement, stabilized requisite propargyl cations, created conformational constraints at the carbon-carbon bond formation site, configurationally altered the acetylenic moiety allowing for 1,3-steric induction upon the newly formed stereocenters, increased bulkiness of propargyl triads thus controlling the spatial orientation of converging radicals, and allowed for α-to-γ projection of the reaction site and alteration of the transiency of radical intermediates. In the course of these studies, a number of popular "beliefs" were proven to be untrue. First, cobalt-complexed propargyl cations, which have long been considered to be thermally labile species, were engaged in synthetically meaningful transformation at temperatures as high as 147 °C. Second, in radical dimerization reactions, higher reaction temperatures did not adversely impact the yields and levels of d,l-diastereoselectivity. Third, π-bonded organometallic radicals, deemed unruly, were effectively controlled with complementary mechanistic tools, thus achieving the highest levels of stereoselectivity (up to 100%) in inter- and intramolecular reactions. Fourth, meso stereoisomers, being thermally labile and kinetically disfavored, were discovered to be major products in intramolecular cyclizations induced by cobaltocene. Fifth, propargyl cations were synthesized in the absence of strong acids, thus increasing the functional tolerance and achieving a long sought after compatibility with acid-sensitive functionalities. A

  17. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  18. Free radical-scavenging capacity, antioxidant activity and phenolic content of Pouzolzia zeylanica

    Directory of Open Access Journals (Sweden)

    PEIYUAN LI

    2011-05-01

    Full Text Available Pouzolzia zeylanica was extracted with different solvents (acetone, ethyl acetate and petroleum ether, using different protocols (cold-extraction and Soxhlet extraction. To evaluate the antiradical and antioxidant abilities of the extracts, four in vitro test systems were employed, i.e., DPPH, ABTS and hydroxyl radical scavenging assays and a reducing power assay. All extracts exhibited outstanding antioxidant activities that were superior to that of butylated hydroxytoluene. The ethyl acetate extracts exhibited the most significant antioxidant activities, and cold-extraction under stirring seemed to be the more efficacious method for acquiring the predominant antioxidants. Furthermore, the antioxidant activities and total phenolic (TP content of different extracts followed the same order, i.e., there is a good correlation between antioxidant activities and TP content. The results showed that these extracts, especially the ethyl acetate extracts, could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.

  19. Targeting excessive free radicals with peels and juices of citrus fruits: grapefruit, lemon, lime and orange.

    Science.gov (United States)

    Guimarães, Rafaela; Barros, Lillian; Barreira, João C M; Sousa, M João; Carvalho, Ana Maria; Ferreira, Isabel C F R

    2010-01-01

    A comparative study between the antioxidant properties of peel (flavedo and albedo) and juice of some commercially grown citrus fruit (Rutaceae), grapefruit (Citrus paradisi), lemon (Citrus limon), lime (Citrusxaurantiifolia) and sweet orange (Citrus sinensis) was performed. Different in vitro assays were applied to the volatile and polar fractions of peels and to crude and polar fraction of juices: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, reducing power and inhibition of lipid peroxidation using beta-carotene-linoleate model system in liposomes and thiobarbituric acid reactive substances (TBARS) assay in brain homogenates. Reducing sugars and phenolics were the main antioxidant compounds found in all the extracts. Peels polar fractions revealed the highest contents in phenolics, flavonoids, ascorbic acid, carotenoids and reducing sugars, which certainly contribute to the highest antioxidant potential found in these fractions. Peels volatile fractions were clearly separated using discriminant analysis, which is in agreement with their lowest antioxidant potential. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Reducing, radical scavenging, and chelation properties of in vitro digests of alcalase-treated zein hydrolysate.

    Science.gov (United States)

    Zhu, Lijuan; Chen, Jie; Tang, Xueyan; Xiong, Youling L

    2008-04-23

    The objective of the study was to assess the antioxidant potential of alcalase-treated zein hydrolysate (ZH) during a two-stage (1 h of pepsin --> 0.5-2 h of pancreatin, 37 degrees C) in vitro digestion. Sephadex gel filtration and high-performance size exclusion chromatography were used to separate ZH into fractions. The amino acid composition, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+*)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH*) free radical scavenging activity, reducing power, and Cu (2+) chelation ability were tested to determine the antioxidant efficacy of ZH. Results showed that in vitro digests of ZH contained up to 16.5% free amino acids, with short peptides (alcalase hydrolysate may have the benefit to promote the health of the human digestive tract.

  1. Radicalization and Radical Catalysis of Biomass Sugars: Insights from First-principles Studies

    OpenAIRE

    Yang, Gang; Zhu, Chang; Zou, Xianli; Zhou, Lijun

    2016-01-01

    Ab initio and density functional calculations are conducted to investigate the radicalization processes and radical catalysis of biomass sugars. Structural alterations due to radicalization generally focus on the radicalized sites, and radicalization affects H-bonds in D-fructofuranose more than in D-glucopyranose, potentially with outcome of new H-bonds. Performances of different functionals and basis sets are evaluated for all radicalization processes, and enthalpy changes and Gibbs free en...

  2. Reaction between protein radicals and other biomolecules

    DEFF Research Database (Denmark)

    Østdal, Henrik; Davies, Michael Jonathan; Andersen, Henrik J

    2002-01-01

    The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2....... Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid...

  3. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-01-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of "narrow mental states"; that is, the idea that the mental content of an individual can be fully characterised without…

  4. [Reprodcutive results of radical trachelectomy].

    Science.gov (United States)

    Martínez-Chapa, Arnulfo; Alonso-Reyes, Nelly; Luna-Macías, Miguel

    2015-12-01

    Historically, cervical cancer in early stages has been treated with radical hysterectomy and radiotherapy with no option in keeping the uterine-ovarian function. Since two decades ago, evidence shows these cases are candidates for radical trachelectomy, a procedure capable of preserving the fertility without affecting the oncological outcome. To analyze reproductive results among patients treated with radical trachelectomy, in a reference center from the northeast of Mexico. Between March 1999 and December 2013, 27 cases with cervical cancer in early stages were treated with vaginal or abdominal radical trachelectomy in the ISSSTE Regional Hospital in Monterrey, NL (Mexico). We obtained the gynecological, medical and surgical clinical history. Plan of analysis consisted of descriptive statistics. Age range was 27-39 years. Main complications were cervical stenosis (n=1) and erosion of cerclaje (n=2). Eighteen patients tried to get pregnant, 8 of them got a spontaneous pregnancy; 1 more patient required assisted reproduction technics and did not succeed. All pregnancies were delivered by cesarean section and were preterm births; 3 underwent premature rupture of membranes. Two pregnancies ended in abortion, one at 10 weeks with severe hemorrhage that needed hysterectomy; the second one, at 1 7 weeks, received a fine uterine curettage. Only 6 cases (33%) got a live birth. Only one third of the attempted pregnancies got a live birth. Assisted reproduction technics play an important role and should be offer to all cases. Cerclaje is an important factor to carry a pregnancy up to the third trimester.

  5. Exploring the Theories of Radicalization

    Directory of Open Access Journals (Sweden)

    Maskaliūnaitė Asta

    2015-12-01

    Full Text Available After the London bombings in July 2005, the concern of terrorism scholars and policy makers has turned to “home-grown” terrorism and potential for political violence from within the states. “Radicalization” became a new buzz word. This article follows a number of reviews of the literature on radicalization and offers another angle for looking at this research. First, it discusses the term “radicalization” and suggests the use of the following definition of radicalization as a process by which a person adopts belief systems which justify the use of violence to effect social change and comes to actively support as well as employ violent means for political purposes. Next, it proposes to see the theories of radicalization focusing on the individual and the two dimensions of his/her motivation: whether that motivation is internal or external and whether it is due to personal choice or either internal (due to some psychological traits or external compulsion. Though not all theories fall neatly within these categories, they make it possible to make comparisons of contributions from a variety of different areas thus reflecting on the interdisciplinary nature of the study of terrorism in general and radicalization as a part of it.

  6. Remembering Dutch-Moluccan radicalism

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2016-01-01

    This article examines memory politics in relation to radical actions of young Dutch-Moluccans, more specifically a train hijacking in 1977 at the village of De Punt in the Netherlands. The article examines how these historical events were remembered in the drama-documentary television film, De Punt...

  7. Is Radical Innovation Management Misunderstood?

    DEFF Research Database (Denmark)

    Kristiansen, Jimmi Normann; Gertsen, Frank

    2015-01-01

    This paper poses a critical view on radical innovation (RI) management research and practice. The study investigates how expected RI performance influences firms’ under- standing of their RI capability. RI performance is often based on output measures such as market shares or fiscal return...

  8. ESR study of free radicals in mango

    Science.gov (United States)

    Kikuchi, Masahiro; Hussain, Mohammad S.; Morishita, Norio; Ukai, Mitsuko; Kobayashi, Yasuhiko; Shimoyama, Yuhei

    2010-01-01

    An electron spin resonance (ESR) spectroscopic study of radicals induced in irradiated fresh mangoes was performed. Mangoes in the fresh state were irradiated with γ-rays, lyophilized and then crushed into a powder. The ESR spectrum of the powder showed a strong main peak at g = 2.004 and a pair of peaks centered at the main peak. The main peak was detected from both flesh and skin specimens. This peak height gradually decreased during storage following irradiation. On the other hand, the side peaks showed a well-defined dose-response relationship even at 9 days post-irradiation. The side peaks therefore provide a useful means to define the irradiation of fresh mangoes.

  9. Free Radical Scavenging and Alpha/Beta-glucosidases Inhibitory Activities of Rambutan (Nephelium lappaceum L. Peel Extract

    Directory of Open Access Journals (Sweden)

    Wahyu Widowati

    2015-12-01

    Full Text Available BACKGROUND: Diabetes mellitus (DM is associated with oxidative reaction and hyperglycemic condition. Human body has an antioxidant defense system toward free radical, but overproduction of free radical causing imbalance condition between the free radical and the antioxidant defense in the body that lead to several diseases, including DM. Glucosidase is an enzyme that hydrolize carbohydrates causing increase of blood glucose level, so by inhibiting this enzyme blood glucose level in plasma could be effectively decreased. Rambutan (Nephelium lappaceum L. peel has been reported to have many potential roles, such as antioxidant and anti-glycemia. Therefore our current study was conducted to evaluate possible effectivity of Rambutan peel to scavenge free radical and to inhibit α- and β-glucosidases. METHODS: Rambutan peel extraction (RPE was performed based on maceration method. Geraniin was used as control. For antioxidant study, 2,2-diphenyl-1- picrylhydrazyl (DPPH free radical scavenging test was performed. For glucosidase inhibitory activity study,  α- and β-glucosidases inhibitory activity tests were performed. Results were analyzed for median of Inhibitory Concentration (IC50. RESULTS: The scavenging activity of RPE was comparable with Geraniin. Meanwhile, the α-glucosidase inhibitory activity of RPE was higher than the one of Geraniin. The α-glucosidase-inhibitory-activity IC50 of RPE and Geraniin were 0.106±0.080 μg/ml and 16.12±0.29 μg/ml, respectively. The β-glucosidase inhibitory activity of RPE was also higher than the one of Geraniin. The β-glucosidase-inhibitory-activity IC50 of RPE and Geraniin were 7.02±0.99 μg/ml and 19.81±0.66 μg/ml, respectively. CONCLUSIONS: Since RPE showed comparable free radical scavenging activity with Geraniin and higher α- and β-glucosidases inhibitory activities than Geraniin, RPE could be suggested as a promising antioxidant and antiglycemic agent.  KEYWORDS

  10. Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Ammu

    2010-09-01

    Full Text Available Abstract Background Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals. Methods The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3 cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS. The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls. Results Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL. The extract reduced significantly (p Conclusions The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.

  11. Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

    Science.gov (United States)

    2010-01-01

    Background Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals. Methods The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls). Results Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring. PMID:20858231

  12. Radical scavenging properties of genistein.

    Science.gov (United States)

    Zielonka, Jacek; Gebicki, Jerzy; Grynkiewicz, Grzegorz

    2003-10-15

    The reactivity of genistein toward reactive radical species has been investigated by means of pulse radiolysis. The values of rate constants, respectively 2.3 x 10(10) M(-1)s(-1) and 1.3 x 10(10) M(-1)s(-1) for the reaction with hydroxyl radical at pH 8.3 and 3.0, are close to diffusion limit indicating that genistein is a potent hydroxyl radical scavenger. The reactivity of genistein towards one-electron oxidants has also been investigated. The rate constants k = 4.6 x 10(9) M(-1)s(-1) (pH 8.3) and 6.7 x 10(8) M(-1)s(-1) (pH 7.6) have been determined for the reaction of genistein with *N3 and Br2*- radicals, respectively. For both oxidants the rate constants at pH 3 does not exceed 10(8) M(-1)s(-1). The differences in reactivity of genistein towards the oxidants at different acidity of the solution have been assumed to arise from the acid-base equilibria of genistein. The dissociation constants for genistein (pKa: 7.2, 10.0, and 13.1) have been evaluated spectroscopically. The influence of acid-base equilibria on bond dissociation energy and ionization potential for genistein has also been investigated by means of DFT calculations. It has been concluded on the basis of these calculations that monoanionic form of genistein existing at physiological pH is more powerful radical scavenger than the neutral molecule.

  13. Biosynthesis of silver nanoparticles from Cavendish banana peel extract and its antibacterial and free radical scavenging assay: a novel biological approach

    Science.gov (United States)

    Kokila, T.; Ramesh, P. S.; Geetha, D.

    2015-11-01

    Biosynthesis of metallic silver nanoparticles has now become an alternative to physical and chemical approaches. In the present study, silver nanoparticles (AgNPs) were synthesized from Cavendish banana peel extract (CBPE) and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Atomic force microscopy (AFM), Field emission scanning electronic microscope (FESEM), Dynamic light scattering (DLS) and zeta potential (ZP). The AgNPs formation was confirmed by UV-visible spectroscopy through color conversion due to surface plasma resonance band at 430 nm. The effect of pH on nanoparticle synthesis was determined by adjusting the various pH of the reaction mixtures. The crystalline nature of nanoparticles was confirmed from the XRD pattern, and the grain size was found to be around 34 nm. To identify the compounds responsible for the bioreduction of Ag+ ion and the stabilization of AgNPs produced, the functional group present in Cavendish banana peel extract was investigated using FTIR. AFM has proved to be very helpful in determining morphological features and the diameter of AgNPs in the range of 23-30 nm was confirmed by FESEM. DLS studies revealed that the average size of AgNPs was found to be around 297 nm. Zeta potential value for AgNPs obtained was -11 mV indicating the moderate stability of synthesized nanoparticles. The antibacterial activity of the nanoparticles was studied against Gram-positive and Gram-negative bacteria. Biosynthesized AgNPs showed a strong DPPH radical and ABTS scavengers compared to the aqueous peel extract of Cavendish banana.

  14. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  15. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  16. UJI TOKSISITAS (Brine Shrimp Lethality Test DAN AKTIVITAS ANTIOKSIDAN DARI DAUN SINTRONG (Crassocephalum Crepidioides DENGAN METODE 2,2-diphenyl-1-picrylhidrazil (DPPH

    Directory of Open Access Journals (Sweden)

    Fiktor Boni Pasilala

    2016-11-01

    Full Text Available The phytochemical test, brine shrimp lethality test and antioxidant activity test on secondary metabolits of terap (Artocarpus odoratissimus B. leaves has been completed. The leaves samples are extracted by masseration method that is concentrated by using rotary evaporator. The total extract are fractioned with n-hexane and ethyl acetate. Based on secondary metabolits phytochemical test of terap (Artocarpus odoratissimus B. leaves showed that total extract and Ethyl Acetat fraction extract contains alkaloids, phenolics, flavonoids, saponins, steroids and triterpenoids. N-hexane fraction extract contain alkaloids, steroids and tritepenoids. In brine shrimp lethality test, the increase larvae death data was recorded and processed using SAS Probit Analysis to determine the Lethal Concentration 50 % (LC50 value. The results of this test showed that the most active extract is metanol extract with LC50 value of 88.0227 ppm. Based on the antioxidant activity by scavenging activity of DPPH used spectrophotometry was obtained that Inhibition Concentration 50% (IC50 of total extract is 369.0833 ppm, extract of n-hexane fraction is 1532.267 ppm and extract of ethyl acetat fraction is 82.89003 ppm.

  17. Oak (Quercus frainetto Ten.) honeydew honey--approach to screening of volatile organic composition and antioxidant capacity (DPPH and FRAP assay).

    Science.gov (United States)

    Jerković, Igor; Marijanović, Zvonimir

    2010-05-25

    Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE) with two solvents (1:2 (v/v) pentane -diethyl ether mixture and dichloromethane) followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%). Antiradical activity (DPPH assay) of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay) of honeydew samples was 4.8 and 16.1 mmol Fe(2+)/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe(2+)/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe(2+)/kg.

  18. Oak (Quercus frainetto Ten. Honeydew Honey—Approach to Screening of Volatile Organic Composition and Antioxidant Capacity (DPPH and FRAP Assay

    Directory of Open Access Journals (Sweden)

    Igor Jerković

    2010-05-01

    Full Text Available Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides. The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE with two solvents (1:2 (v/v pentane -diethyl ether mixture and dichloromethane followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%. Antiradical activity (DPPH assay of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay of honeydew samples was 4.8 and 16.1 mmol Fe2+/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe2+/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe2+/kg.

  19. Flavonoids as scavengers of nitric oxide radical.

    NARCIS (Netherlands)

    van Acker, S.A.B.E.; Tromp, M.N.J.L.; Haenen, G.R.M.M.; van der Vijgh, W.J.F.; Bast, A.

    1995-01-01

    Flavonoids are a group of naturally occurring compounds used, e.g., in the treatment of vascular endothelial damage. They are known to be excellent scavengers of oxygen free radicals. Since the nitric oxide radical (

  20. Reaction between protein radicals and other biomolecules

    DEFF Research Database (Denmark)

    Østdal, Henrik; Davies, Michael Jonathan; Andersen, Henrik J

    2002-01-01

    The present study investigates the reactivity of bovine serum albumin (BSA) radicals towards different biomolecules (urate, linoleic acid, and a polypeptide, poly(Glu-Ala-Tyr)). The BSA radical was formed at room temperature through a direct protein-to-protein radical transfer from H(2)O(2......)-activated immobilized horseradish peroxidase (im-HRP). Subsequently, each of the three different biomolecules was separately added to the BSA radicals, after removal of im-HRP by centrifugation. Electron spin resonance (ESR) spectroscopy showed that all three biomolecules quenched the BSA radicals....... Subsequent analysis showed a decrease in the concentration of urate upon reaction with the BSA radical, while the BSA radical in the presence of poly(Glu-Ala-Tyr) resulted in increased formation of the characteristic protein oxidation product, dityrosine. Reaction between the BSA radical and a linoleic acid...

  1. Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

    Directory of Open Access Journals (Sweden)

    Takayuki Mokudai

    Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

  2. Photoisomerization and photodissociation dynamics of reactive free radicals

    Energy Technology Data Exchange (ETDEWEB)

    Bise, Ryan T. [Univ. of California, Berkeley, CA (United States)

    2000-08-01

    transition state. In contrast to the radicals mentioned above, resolved vibrational structure was not observed for the ICNN radical due to extensive fragment rotational excitation, suggesting that intermediate bent states are strongly coupled along the dissociation pathway. The measurements performed in this Thesis have additionally refined the heats of formation and bond dissociation energies of these radicals and have unambiguously confirmed and added to the known electronic spectroscopy.

  3. Characterization of fatty acids, bioactive lipids, and radical scavenging activity of Canterbury bells seed oil

    Directory of Open Access Journals (Sweden)

    Hassanien, M. F.R.

    2014-06-01

    Full Text Available The aim of this study was to characterize the chemical composition and radical scavenging activity of Canterbury bells (Campanula medium seed oil. C. medium seeds contained 9.2% extractable oil. The lipid classes, fatty acids, phytosterol and tocopherol composition of C. medium seed oil were determined. The amount of neutral lipids in the oil was the highest, followed by glycolipids and phospholipids. Linoleic and oleic were the main fatty acids. C. medium oil is characterized by high levels of phytosterols and β-sitosterol was the main compound. β-Tocopherol constituted 42.5% of the total tocopherol content followed by γ-tocopherol. The radical scavenging activity (RSA toward 1,1-diphenyl-2-picrylhydrazyl (DPPH radicals and galvinoxyl radicals of C. medium oil were higher than those of extra virgin olive oil. The diverse potential uses of C. medium oil may make this plant industrially important.El objetivo de este estudio fue caracterizar la composición química y la actividad de captación de radicales de aceites de semillas de campanillas de Canterbury (Campanula medium. Las semillas de C. medium contenían 9,2 % de aceite extraíble. Se determinó la composición de las diferentes clases de lípidos, ácidos grasos, fitoesteroles y tocoferoles. La cantidad de lípidos neutros en el aceite fue mayoritario, seguido de glicolípidos y fosfolípidos. Linoleico y oleico fueron los ácidos grasos principales. El aceite de C. medium se caracteriza por altos niveles de fitoesteroles y β-sitosterol fue el compuesto principal. β-tocoferol constituía 42,5 % del contenido total de tocoferol seguido de γ-tocoferol. La actividad de captación de radicales (RSA a 1,1-difenil-2- picrilhidrazil (DPPH y radicales galvinoxil de C. medium fueron superiores a las de aceite de oliva virgen extra. Los diversos usos potenciales de los aceites de C. medium pueden hacer que esta planta pueda ser importante industrialmente.

  4. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  5. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  6. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  7. Geoscientists and the Radical Middle

    Science.gov (United States)

    Tinker, S. W.

    2015-12-01

    Addressing the great challenges facing society requires industry, government, and academia to work together. I call this overlap space, where compromises are made and real solutions determined, the Radical Middle. Radical because it can appear at times as if the loudest and most publicly influential voices lie outside of the actual solution space, content to provoke but not problem-solve. One key area where geoscientists can play a lead role in the Radical Middle is in the overlap between energy, the environment, and the economy. Globally, fossil fuels still represent 85% of the aggregate energy mix. As existing conventional oil and natural-gas reservoir production continues to slowly decline, unconventional reservoirs, led today by shale and other more expensive resources, will represent a growing part of the oil and gas production mix. Many of these unconventional reservoirs require hydraulic fracturing. The positive economic impact of hydraulic fracturing and associated natural gas and oil production on the United States economy is well documented and undeniable. Yet there are environmental concerns about fracking, and some states and nations have imposed moratoria. This energy-environment-economy space is ideal for leadership from the geosciences. Another such overlap space is the potential for geoscience leadership in relations with China, whose economy and global presence continue to expand. Although China is building major hydropower and natural-gas power plants, as well as nuclear reactors, coal is still king—with the associated environmental impacts. Carbon sequestration—onshore in brine and to enhance oil recovery, as well as offshore—could prove viable. It is vital that educated and objective geoscientists from industry, government, and academia leave their corners and work together in the Radical Middle to educate the public and develop and deliver balanced, economically sensible energy and environmental strategies.

  8. Free radical mediated cellulose degradation

    OpenAIRE

    Johansson, Erik

    2003-01-01

    This thesis addresses the mechanisms involved in cellulosedegradation in general and Totally Chlorine Free (TCF) bleachingof pulp in particular. The thesis shows that the cellulosedegradation during high consistency ozone bleaching is explainedby free radical chain reactions. By simulation, it has been shown that the number, weight andviscosity average of liner polymer chain length can be used tocalculate the number of random scissions in a linear polymer ofany molecular weight distribution, ...

  9. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  10. In vitro alpha glucosidase inhibition and free-radical scavenging activity of propolis from Thai stingless bees in mangosteen orchard

    Directory of Open Access Journals (Sweden)

    Boonyadist Vongsak

    Full Text Available ABSTRACTThe chemical component and biological activity of propolis depend on flora area of bee collection and bee species. In the study, the propolis from three stingless bee species, Lepidotrigona ventralis Smith, Lepidotrigona terminata Smith, and Tetragonula pagdeni Schwarz, was collected in the same region of mangosteen garden from Thailand. Total phenolic content, alpha glucosidase inhibitory effect, and free-radical scavenging activity using FRAP, ABTS, DPPH assays were determined. The most potent activity of propolis extract was investigated for bioactive compounds and their quantity. The ethanol extract of T. pagdeni propolis had the highest total phenolic content 12.83 ± 0.72 g of gallic acid equivalents in 100 g of the extract, and the strongest alpha glucosidase inhibitory effect with the IC50 of 70.79 ± 6.44 µg/ml. The free-radical scavenging activity evaluated by FRAP, ABTS, DPPH assays showed the FRAP value of 279.70 ± 20.55 µmol FeSO4 equivalent/g extract and the IC50 of 59.52 ± 10.76 and 122.71 ± 11.76 µg/ml, respectively. Gamma- and alpha-mangostin from T. pagdeni propolis extract were isolated and determined for the biological activity. Gamma-mangostin exhibited the strongest activity for both alpha glucosidase inhibitory effect and free-radical scavenging activity. Using HPLC quantitative analysis method, the content of gamma- and alpha-mangostin in the extract was found to be 0.94 ± 0.01 and 2.77 ± 0.08% (w/w, respectively. These findings suggested that T. pagdeni propolis may be used as a more suitable raw material for nutraceutical and pharmaceutical products and these mangostin derivatives as markers.

  11. Anti-inflammatory and free radical scavenging activities of ethanol extracts of three seeds used as "Bolengguazi".

    Science.gov (United States)

    Fang, Qing Mao; Zhang, Hao; Cao, Yu; Wang, Can

    2007-10-08

    The seeds of Herpetospermum pedunculosun (Ser.) C.B.Clarke. (HPD), Mormodica cochinchinensis (Lour.) Spreng. (MCC) and Mormodica charantia L. (MCR) share the same common name ("Bolengguazi") in the Tibetan medicine. The anti-inflammatory activities of the three "Bolengguazi" were evaluated using egg album-induced paw edema and cotton-pellet granuloma tests. Among them, HPD is the most active one in both models. Results showed that oral administration of ethanol extract of HPD seed (200 and 400mg/kg) significantly suppressed the development of egg albumin-induced paw edema (P<0.01). In the chronic test, the ethanol extract of HPD seed (200 and 400mg/kg) showed significant reduction in granuloma weight of rats (P<0.05). The anti-inflammatory effect of the ethanol HPD seed was similar to that of indomethacin (10mg/kg). Moreover, the free radical scavenging activities of "Bolengguazi" were investigated using the DPPH test. Only the ethanol extract of HPD seed showed a moderate free radical scavenging effect on DPPH (IC50, 198.69 microg/ml) when compared with the positive control, V(E), (IC50, 44.91 microg/ml). The HPD seeds showed more significant anti-inflammatory activities in additional to higher free radical scavenging activities than that of the MCC and MCR seeds. The results of the present study provide a scientific basis to explain, in part, the popular use of HPD seed in Tibetan folk medicine as "Bolengguazi". The present study also supports the claims by the traditional Tibetan medicine practitioners about the use of HPD seeds in inflammatory diseases, such as "Chiba".

  12. Chemical composition and radical scavenging activity of essential oil and methanolic extract of Eremostachys azerbaijanica Rech.f. from Iran.

    Science.gov (United States)

    Asnaashari, Solmaz; Afshar, Fariba Heshmati; Ebrahimi, Atefeh; Moghadam, Sedigheh Bamdad; Delazar, Abbas

    2016-01-01

    In the present study, the chemical composition of the essential oil and methanol (MeOH) extract of aerials of E. azerbaijanica were identified. Furthermore, the free radical scavenging properties of the volatile oil as well as the MeOH extract of the plant were assessed. The essential oil of the air-dried aerial parts was obtained by hydro-distillation using a Clevenger-type apparatus. The oil was then analyzed by gas chromatography-mass spectrometry and gas chromatography with flame ionization detector. Soxhlet extraction was performed on the aerial parts using n-hexane, dichloromethane and MeOH. The MeOH extract was then subjected to solid-phase extraction using a C18 Sep-Pak cartridge. Isolation and structural elucidation of the pure components was accomplished by high-performance liquid chromatography and spectroscopic methods (UV, (1)H-NMR). The free radical scavenging properties were determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. A total of 59 components representing 95.9% of the oil constituents were identified which were primarily characterized as terpenoids or aliphatic skeletons. The major components of the oil were hexahydrofarnesyl acetone (27.1%), 2-methyl-6-propyl-dodecane (16.4%) and tricosane (9.3%). One flavonoid (luteolin-7-O-rutinoside) and one phenylethanoid (verbascoside) were also isolated and identified from the MeOH extract. The results of DPPH assays showed that the essential oil of E. azerbaijanica possessed weak free radical scavenging activity whereas the MeOH extract and its pure constituents showed significant scavenging activities in comparison with positive controls.

  13. UV-visible spectrum of the phenyl radical and kinetics of its reaction with NO in the gas phase

    DEFF Research Database (Denmark)

    Wallington, T.J.; Egsgaard, H.; Nielsen, O.J.

    1998-01-01

    Pulse radiolysis transient UV-visible absorption spectroscopy was used to study the UV-visible absorption spectrum (225-575 nm) of the phenyl radical, C6H5(.), and kinetics of its reaction with NO. Phenyl radicals have a strong broad featureless absorption in the region of 225-340 nm...

  14. Oxidative stress, free radicals and protein peroxides.

    Science.gov (United States)

    Gebicki, Janusz M

    2016-04-01

    Primary free radicals generated under oxidative stress in cells and tissues produce a cascade of reactive secondary radicals, which attack biomolecules with efficiency determined by the reaction rate constants and target concentration. Proteins are prominent targets because they constitute the bulk of the organic content of cells and tissues and react readily with many of the secondary radicals. The reactions commonly lead to the formation of carbon-centered radicals, which generally convert in vivo to peroxyl radicals and finally to semistable hydroperoxides. All of these intermediates can initiate biological damage. This article outlines the advantages of the application of ionizing radiations to studies of radicals, with particular reference to the generation of desired radicals, studies of the kinetics of their reactions and correlating the results with events in biological systems. In one such application, formation of protein hydroperoxides in irradiated cells was inhibited by the intracellular ascorbate and glutathione. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Youth De-Radicalization: A Canadian Framework

    Directory of Open Access Journals (Sweden)

    Hafal (Haval Ahmad

    2017-09-01

    Full Text Available Youth radicalization leading to violence has become a growing fear among Canadians, as terrorist attacks are carried out in Western states. Although Canada has suffered relatively fewer acts of violence, this fear has intensified and a de-radicalization strategy is needed in the Canadian context. In a qualitative case study methodology, interviews were conducted with school counsellors, religious leaders, and academics to explore solutions to youth radicalization. Youth de-radicalization approaches from the United Kingdom were analyzed and found that community-based initiatives were missing from programming. Social identity theory is used to explain that youth join radicalized groups to feel a sense of belonging and have to be provided an alternative and moderate group identity to de-radicalize. This study found youth de-radicalization in Canada is best served through a community collaboration approach.

  16. EPR and optical spectroscopic studies of neutral free radicals in an adamantane matrix

    International Nuclear Information System (INIS)

    Jordan, J.E.

    1975-03-01

    Recent work in our laboratory has demonstrated that neutral free radicals produced by x-irradiation and trapped in adamantane exhibit exceedingly long lifetimes because of the lack of rapid diffusion in the solid matrix. This observation and the fact that samples can be pressed into pellets with high optical transparency in the visible and near uv regions of the spectrum suggested to us that this unique matrix might be used for studying the optical properties of free radicals. The results of a wide variety of experiments of this type are described in this thesis. These include experiments in which secondary free radicals are produced by photoinduced decomposition of primary free radicals by selective irradiation with visible light, the observation of strong optical absorption spectra of free radicals at room temperature using a Cary 14 spectrophotometer, the finding that certain free radicals exhibit strong, visible fluorescence when irradiated with uv light, and the discovery that the absorption intensity of multiplicity-forbidden transition in singlet and doublet state species is enhanced relative to spin-allowed transitions by at least three orders of magnitude. An analysis of these results in terms of molecular orbital theory is given, and experiments designed to obtain the epr spectra of electronically-excited states of free radicals are described

  17. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  18. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  19. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  20. Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals.

    Science.gov (United States)

    Slezák, J; Kura, B; Frimmel, K; Zálešák, M; Ravingerová, T; Viczenczová, C; Okruhlicová, Ľ; Tribulová, N

    2016-09-19

    Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

  1. Radical Technological Innovation–Comparison of a Critical Success Factors Framework with Existing Literature

    OpenAIRE

    Florian Wohlfeil; Orestis Terzidis; Louisa Hellmann

    2015-01-01

    Radical technological innovations enable companies to reach strong market positions and are thus desirable. On the other hand, the innovation process is related to significant costs and risks. Hence, the knowledge of the factors that influence success is crucial for technology driven companies. Taking a previously developed framework of Critical Success Factors for radical technological innovations as a reference model, we conducted a structured and focused literature rev...

  2. Effect of some free radicals on superoxide dismutase and ...

    African Journals Online (AJOL)

    Free radicals are species with unpaired electron in their outermost shell. Most free radicals come from oxygen or nitrogen atoms. Radical species such as superoxide radical, hydroxyl radicals and hydrated electron are called the primary radicals of water radiolysis and can be produced by irradiating water molecule.

  3. Effects of radical scavengers on aqueous solutions exposed to heavy-ion irradiation using the liquid microjet technique

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Shinji [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Tsuchida, Hidetsugu, E-mail: tsuchida@nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan); Furuya, Ryousuke; Miyahara, Kento [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Majima, Takuya; Itoh, Akio [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan)

    2015-12-15

    The effects of the radical scavenger ascorbic acid on water radiolysis are studied by fast heavy-ion irradiation of aqueous solutions of ascorbic acid, using the liquid microjet technique under vacuum. To understand the reaction mechanisms of hydroxyl radicals in aqueous solutions, we directly measure secondary ions emitted from solutions with different ascorbic acid concentrations. The yield of hydronium secondary ions is strongly influenced by the reaction between ascorbic acid and hydroxyl radicals. From analysis using a simple model considering chemical equilibria, we determine that the upper concentration limit of ascorbic acid with a radical scavenger effect is approximately 70 μM.

  4. Online radicalization: the net or the netizen?

    Directory of Open Access Journals (Sweden)

    Femi Richard Omotoyinbo

    2014-10-01

    Full Text Available Purpose - Radicalization has gained some unusual prominence in the academic circles; maintaining a generic existence not only in the political sector. And with the advent of the Information Communication Technology (ICT, radicalization has begun to have some virtual dimension even in the remotest of human communities. This study seeks to mobilize a universal awareness on the collective urgency to oppose Online Radicalization (a radicalization that happens through the internet due to its propensity to engendering conflicts. It also aims at identifying the principal cause of online radicalization and steer a clear course for a practical reversal in the systems of online radicalization.Design/methodology/approach - The study is divided into three primary parts. The general notion of radicalization is the focus of the first part; which is further analysed into the levels of online radicalization with its accompanying developments and segments. The second part utilizes analytic and historical method to pinpoint the principal cause of online radicalization amidst the suspected causal factors (the Net and the Netizen. The final part analytically focuses on the Netizen (a user/citizen of the internet as the primary cause of online radicalization, and how the global community can bring about a corresponding change in the Net by the application of some measures on the Netizen.Findings - By virtue of the analytic plus historical methods employed by this study; it was initially identified that radicalization is basically having two versions which are online and offline. Further emphasis on the online version reveals that its existence is only made possible by the availability of the internet (the Net. Since the Net is a global phenomenon online radicalization is considered to be worldwide: a menace of globalization. However, the study later indicated that the Net is a facilitator and a cause of online radicalization. A view was deduced that the Netizen is

  5. Iron and iron derived radicals

    International Nuclear Information System (INIS)

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fast! Think small! In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab

  6. Laser spectroscopy of hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P. [Harvard Univ., Cambridge, MA (United States)

    1993-12-01

    The author reports the application of supersonic jet flash pyrolysis to the specific preparation of a range of organic radicals, biradicals, and carbenes in a skimmed molecular beam. Each species was produced cleanly and specifically, with little or no secondary reactions by the thermal dissociation of appropriately designed and synthesized organic precursors. Photoelectron spectra of the three isomeric C{sub 3}H{sub 2} carbenes, ortho-benzyne, and the {alpha},3-dehydrotoluene biradical, were used to establish adiabatic ionization potentials for use in thermochemical determinations.

  7. Aromatic-radical oxidation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Glassman, I.; Brezinsky, K. [Princeton Univ., NJ (United States)

    1993-12-01

    The research effort has focussed on discovering an explanation for the anomalously high CO{sub 2} concentrations observed early in the reaction sequence of the oxidation of cyclopentadiene. To explain this observation, a number of plausible mechanisms have been developed which now await experimental verification. One experimental technique for verifying mechanisms is to probe the reacting system by perturbing the radical concentrations. Two forms of chemical perturbation of the oxidation of cyclopentadiene were begun during this past year--the addition of NO{sub 2} and CO to the reacting mixture.

  8. Free radical kinetics of irradiated durum wheat

    International Nuclear Information System (INIS)

    Korkmaz, M.; Polat, M.

    2000-01-01

    In the present work, a detailed ESR investigation of characteristic features and kinetic behaviors at three different temperatures of free radicals produced in a species of durum wheat cultivated in Turkey and irradiated at doses of up to 5 kGy by a γ source, is reported. Unirradiated wheat samples exhibit a weak, single-line ESR signal originating from a radical of unknown structure called radical III in this work. Irradiation produces two more radicals identified as hydroxyalkyl (I) and aldehydalkyl (II) radicals beside radical III. The radicals (I, II and III) follow complicated kinetics. Species I and II initially decay very fast after the irradiation followed by slower decay. Radical half-life times depend on whether they were induced in the crystalline or amorphous fractions of the wheat starch. Activation energy values of the radicals were found to follow the order E a (III)>E a (II)>E a (I). ESR parameters of the radical species were determined by simulating experimental spectra recorded following the irradiation. Room temperature dose-response curves and variations of different spectral parameters between 120 and 390 K were also studied

  9. Free radical kinetics of irradiated durum wheat

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, M.; Polat, M

    2000-04-01

    In the present work, a detailed ESR investigation of characteristic features and kinetic behaviors at three different temperatures of free radicals produced in a species of durum wheat cultivated in Turkey and irradiated at doses of up to 5 kGy by a {gamma} source, is reported. Unirradiated wheat samples exhibit a weak, single-line ESR signal originating from a radical of unknown structure called radical III in this work. Irradiation produces two more radicals identified as hydroxyalkyl (I) and aldehydalkyl (II) radicals beside radical III. The radicals (I, II and III) follow complicated kinetics. Species I and II initially decay very fast after the irradiation followed by slower decay. Radical half-life times depend on whether they were induced in the crystalline or amorphous fractions of the wheat starch. Activation energy values of the radicals were found to follow the order E{sub a}(III)>E{sub a}(II)>E{sub a}(I). ESR parameters of the radical species were determined by simulating experimental spectra recorded following the irradiation. Room temperature dose-response curves and variations of different spectral parameters between 120 and 390 K were also studied.

  10. Radical constructivism: Between realism and solipsism

    Science.gov (United States)

    Martínez-Delgado, Alberto

    2002-11-01

    This paper criticizes radical constructivism of the Glasersfeld type, pointing out some contradictions between the declared radical principles and their theoretical and practical development. These contradictions manifest themselves in a frequent oscillation between solipsism and realism, despite constructivist claims to be an anti-realist theory. The paper also points out the contradiction between the relativism of the radical constructivist principles and the constructivist exclusion of other epistemological or educational paradigms. It also disputes the originality and importance of the radical constructivist paradigm, suggesting the idea of an isomorphism between radical constructivist theory and contemplative realism. In addition, some pedagogical and scientific methodological aspects of the radical constructivist model are examined. Although radical constructivism claims to be a rational theory and advocates deductive thinking, it is argued that there is no logical deductive connection between the radical principles of constructivism and the radical constructivist ideas about scientific research and learning. The paper suggests the possibility of an ideological substratum in the construction and hegemonic success of subjective constructivism and, finally, briefly advances an alternative realist model to epistemological and educational radical constructivism.

  11. Synthesis, Characterization, Antimicrobial Screening and Free-Radical Scavenging Activity of Some Novel Substituted Pyrazoles

    Directory of Open Access Journals (Sweden)

    Nagwa Mohamed Mahrous Hamada

    2015-06-01

    Full Text Available The present work deals with the synthesis of acetoxysulfonamide pyrazole derivatives, substituted 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives starting from substituted vanillin chalcones. Acetoxysulfonamide pyrazole derivatives were prepared from the reaction of chalcones with p-sulfamylphenylhydrazine followed by treatment with acetic anhydride. At the same time 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives were prepared from the reaction of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide, respectively. The synthesized compounds were structurally characterized on the basis of IR, 1H-NMR, 13C-NMR spectral data and microanalyses. All of the newly isolated compounds were tested for their antimicrobial activities. The antimicrobial screening using the agar well-diffusion method revealed that the chloro derivatives are the most active ones. Moreover, the antioxidant and anti-inflammatory activity of these chloro derivatives are also studied using the DPPH radical scavenging and NO radical scavenging methods, respectively.

  12. Free radical scavenging and anti-edematogenic activities of Paullinia elegans Cambess., Sapindaceae, leaves extracts

    Directory of Open Access Journals (Sweden)

    Rodrigo N. Guimarães

    Full Text Available Ethanol extract of the leaves of Paullinia elegans Cambess., Sapindaceae, and its hexane, chloroform, ethyl acetate, and hydroethanol fractions were evaluated for their antiedematogenic and free radical scavenging activities. The ethanol extract and the hexane fraction produced statistically significant inhibition (74.4 and 76.0%, respectively of the ear edema induced by croton oil in mice, observed at doses of 5 mg/ear. The ethyl acetate and hydroethanol fractions showed significant radical scavenging effect in the DPPH assay, with IC50 of 36.7 and 30.1 µg/mL, respectively. Fractionation of the extracts through chromatographic methods afforded epifriedelanol, oleanolic acid 3-O-acetyl, a mixture of stigmasterol 3-β-O-glucopyranoside and sitosterol 3-β-O-glucopyranoside, kaempferol 3,7-O-α-dirhamnopyranoside, kaempeferol-3-O-α-rhamnopyranoside and 2-O-methyl-chiro-inositol. The compounds were identified on the basis of their NMR spectral data and comparison with those of literature.

  13. Evaluation of antioxidant, free radical scavenging and antimicrobial, activity of Quercus incana Roxb.

    Directory of Open Access Journals (Sweden)

    Rizwana eSarwar

    2015-11-01

    Full Text Available Considering the indigenous utilization of Quercus incana Roxb., the present study deals with the investigation of antioxidant, free radical scavenging activity, total phenolic content and antimicrobial activity of Quercus incana Roxb. In vitro antioxidant activity of the plant fractions were determined by DPPH and NO scavenging method. Total phenolic contents were determined by gallic acid equivalent (GAE and antimicrobial activities were determined by agar well diffusion method. It was observed that Quercus incana Roxb. showed significant antibacterial activity against Gram-positive and Gram-negative bacteria. n-Butanol fraction showed maximum activity against Micrococcus leuteus with 19 mm zone of inhibition. n-Butanol fraction of Quercus incana Roxb. showed immense antifungal activity against Aspergillus niger (32 mm ± 0.55 and Aspergillus flavus (28 mm ± 0.45. Similarly n-butanol fraction showed relatively good antioxidant activity with IC50 value of 55.4 ± 0.21μg/mL. The NO scavenging activity of ethyl acetate fraction (IC50 = 23.21 ± 0.31 μg/mL was fairly good compared to other fractions. The current study of Quercus incana Roxb. suggests the presences of synergetic action of some biological active compounds that may be present in the leaves of medicinal plant. Further studies are needed to better characterize the important active constituents responsible for the antimicrobial, antioxidant and free radical scavenging activity.

  14. Chlorophytum borivilianum as potential terminator of free radicals in various in vitro oxidation systems.

    Science.gov (United States)

    Visavadiya, Nishant P; Soni, Badrish; Dalwadi, Nirav; Madamwar, Datta

    2010-04-01

    Chlorophytum borivilianum is a very popular herb in traditional Indian medicine and used as a potent "Rasayana" drug in "Ayurveda" as a rejuvenator. Currently, a large body of evidence supports the key role of free radicals in diverse pathological conditions such as aging and atherosclerosis. The present investigation essentially focuses on the comprehensive account of in vitro antioxidant activity exerted by C.borivilianum root extracts (i.e., aqueous and ethanolic), to clarify the pharmacological antagonism of chemicals/metals-mediated oxidation. Graded-dose (25 to 1000 microg/ml) of aqueous extract exhibited higher antioxidant potency as evidenced by powerful nitric oxide, superoxide, hydroxyl, DPPH and ABTS(*+) radicals scavenging activity along with reducing capacity (Fe(3+)/ferricyanide complex and FRAP assays), metal chelating ability, as well as markedly suppressed the lipid peroxidation in mitochondrial fractions as compared to ethanolic extract. Further, aqueous extract significantly decreased (P borivilianum root has significant powerful antioxidant activity and may favorably affect atherosclerosis risk status by reducing LDL oxidation susceptibility.

  15. Radical Scavenging Activities of Tannin Extracted from Amaranth (Amaranthus caudatus L.).

    Science.gov (United States)

    Jo, Hyeon-Ju; Chung, Kang-Hyun; Yoon, Jin A; Lee, Kwon-Jai; Song, Byeong Chun; An, Jeung Hee

    2015-06-01

    This study investigates the bioactivity of tannin from amaranth (Amaranthus caudatus L.) extracts. The antioxidant activities of the extracts from amaranth leaves, flowers, and seeds were evaluated. Tannin from leaves of amaranth has been evaluated for superoxide scavenging activity by using DPPH and ABTS(+) analysis, reducing power, protective effect against H2O2-induced oxidative damage in L-132 and BNL-CL2 cells, and inhibition of superoxide radical effects on HL-60 cells. At a concentration of 100 μg/ml, tannin showed protective effects and restored cell survival to 69.2% and 41.8% for L-132 and BNL-CL2 cells, respectively. Furthermore, at the same concentration, tannin inhibited 41% of the activity of the superoxide radical on HL-60 cells and 43.4% of the increase in nitric oxide levels in RAW 264.7 cells. The expression levels of the antioxidant-associated protein SOD-1 were significantly increased in a concentration-dependent manner in RAW 264.7 cells treated with tannin from amaranth leaves. These results suggest that tannin from the leaves of Amaranthus caudatus L. is a promising source of antioxidant component that can be used as a food preservative or nutraceutical.

  16. Free radical scavengers from the aerial parts of Grammosciadium platycarpum Boiss. & Hausskn. (Apiaceae and GC-MS analysis of the essential oils from its fruits

    Directory of Open Access Journals (Sweden)

    Hossein Nazemiyeh

    2010-05-01

    Full Text Available Grammosciadium platycarpum Boiss. & Hausskn (Apiaceae is one of three endemic Iranian species of the genus Grammosciadium DC. Consumption of the aerial parts of this plant affects renal function and causes diuresis. In the DPPH assay the methanol extract showed the highest level of free radical scavenging activity (RC50 = 1.196 x 10-2 mg/mL among the extracts. Reversed-phase preparative HPLC analyses of the methanol extract yielded nine flavonoids, which were responsible for the free radical scavenging activity of the MeOH extract. The GC-MS analyses of the essential oils led to the identification of 29 terpenoids, mainly monoterpenes (non-oxygenated 3.97% and oxygenated 77.49% accounting for over 96% of the total oils.

  17. Night-time radical chemistry during the NAMBLEX campaign

    Directory of Open Access Journals (Sweden)

    R. Sommariva

    2007-01-01

    Full Text Available Night-time chemistry in the Marine Boundary Layer has been modelled using a number of observationally constrained zero-dimensional box-models. The models were based upon the Master Chemical Mechanism (MCM and the measurements were taken during the North Atlantic Marine Boundary Layer Experiment (NAMBLEX campaign at Mace Head, Ireland in July–September 2002. The model could reproduce, within the combined uncertainties, the measured concentration of HO2 (within 30–40% during the night 31 August–1 September and of HO2+RO2 (within 15–30% during several nights of the campaign. The model always overestimated the NO3 measurements made by Differential Optical Absorption Spectroscopy (DOAS by up to an order of magnitude or more, but agreed with the NO3 Cavity Ring-Down Spectroscopy (CRDS measurements to within 30–50%. The most likely explanation of the discrepancy between the two instruments and the model is the reaction of the nitrate radical with inhomogeneously distributed NO, which was measured at concentrations of up to 10 ppt, even though this is not enough to fully explain the difference between the DOAS measurements and the model. A rate of production and destruction analysis showed that radicals were generated during the night mainly by the reaction of ozone with light alkenes. The cycling between HO2/RO2 and OH was maintained during the night by the low concentrations of NO and the overall radical concentration was limited by slow loss of peroxy radicals to form peroxides. A strong peak in [NO2] during the night 31 August–1 September allowed an insight into the radical fluxes and the connections between the HOx and the NO3 cycles.

  18. Radicalization In Pakistan And The Spread Of Radical Islam In Pakistan

    Directory of Open Access Journals (Sweden)

    Bahir ahmad

    2015-08-01

    Full Text Available ABSTRACT It is pertinent to mention that radicalism is not intrinsic to Islam and radical interpretations of the religion or for that matter may occur within any way of life and religion Saikal 2003 and yet the question remains as to why Muslims in certain geographical regions have more radical approaches towards their religion and also that what are the causes of such radicalization. Becoming a radical Muslim is not even a matter of a day nor is it a sudden process. There are several reasons behind making a person radical peaceful angry smiling or tolerant. For knowing the reason behind radicalization or radicals persons one has to understand the causes. Tracing these causes is one of the ways to eliminate such behavior. The first step in the elimination of the radical sentiments in a person is to develop peace in his personality Fair Malhotra amp Shapiro 2010. The chapter which has been addressed here is going to shed light on the roots and symptoms of the radicalism. There will be a brief discussion on how the roots of radicalism can be traced and can be eliminated. The assessment and discussion will be conducted on the parameters of the economy media politics and theology from social cultural point of view. According to the analysis of Ahrari 2000 political factor is one of the major and direct factors which have resulted in causing of the radicalism. These factors however intertwine with one another. Radical actions cannot take place only because of the political factors.

  19. Western Radicalization: Rethinking the Psychology of Terrorism

    Science.gov (United States)

    2017-03-01

    RADICALIZATION: RETHINKING THE PSYCHOLOGY OF TERRORISM by Vern Pierson March 2017 Thesis Co-Advisors: Mohammed Hafez John Rollins THIS PAGE...thesis 4. TITLE AND SUBTITLE WESTERN RADICALIZATION: RETHINKING THE PSYCHOLOGY OF TERRORISM 5. FUNDING NUMBERS 6. AUTHOR(S) Vern Pierson 7...terrorists are engaging in political “group speak” and are by nature psychologically “normal.” Thus, anyone is susceptible to radicalization. To counter

  20. Research progress on trifluoromethyl-based radical reaction process

    Science.gov (United States)

    Song, Hao

    2017-12-01

    Due to the unique properties imparted by the trifluoromethyl group, such as high electron density and strong lipotropy, which effectively improve acidity, lipophilicity and metabolic stability of the molecule itself, trifluoromethyl-substituted organic compounds are becoming increasingly important as structural motifs in pharmaceuticals, agrochemicals and organic materials. In this review, we present several methods developed for the direct introduction of a trifluoromethyl group, beginning with its rich and storied history. Then the present article addresses mechanism and process in carbon-carbon bond forming reaction based on radical process which is divided into three parts according to the way of CF3 radical generation. Finally, challenges and opportunities of researches on trifluoromethylation reactions facing are prospected.

  1. Dynamics of Radical-Mediated Enzyme Catalyses

    Science.gov (United States)

    Warncke, Kurt

    1997-11-01

    An emergent class of enzymes harnesses the extreme reactivity of electron-deficient free radical species to perform some of the most difficult reactions in biology. The regio- and stereo-selectivity achieved by these enzymes defies long-held ideas that radical reactions are non-specific. The common primary step in these catalyses is metal- or metallocenter-assisted generation of an electron-deficient organic "initiator radical". The initiator radical abstracts a hydrogen atom from the substrate, opening a new reaction channel for rearrangement to the product. Our aim is to elucidate the detailed molecular mechanisms of the radical pair separation and radical rearrangement steps. Radical pair separation and substrate radical rearrangement are tracked by using time-resolved (10-7 to 10-3 s) techniques of pulsed-electron paramagnetic resonance spectroscopy (FT-EPR, ESEEM). Synchronous time-evolution of the reactions is attained by triggering with a visible laser pulse. Transient non-Boltzmann population of the states of the spin-coupled systems, and resultant electron spin polarization, facilitates study at or near room temperature under conditions where the enzymes are operative. The systems examined include ethanolamine deaminase, a vitamin B12 coenzyme-dependent enzyme, ribonucleotide reductase and photosynthetic reaction centers. The electronic and nuclear structural and kinetic information obtained from the pulsed-EPR studies is used to address how the initiator radicals are stabilized against deleterious recombination with the metal, and to distinguish the participation of concerted versus sequential rearrangement pathways.

  2. Assessment of in vitro antimicrobial potency and free radical scavenging capacity of the essential oil and ethanol extract of Calycotome villosa subsp. intermedia growing in Algeria

    Directory of Open Access Journals (Sweden)

    Ilyas Chikhi

    2014-10-01

    Full Text Available Objective: To assess the antimicrobial and antioxidant activity of the essential oil and ethanol extract of the aerial parts of Calycotome villosa subsp. intermedia growing in the West Northern region of Algeria. Methods: Chemical composition of essential oils obtained by hydrodistillation from areal parts of Calycotome villosa subsp. intermedia was investigated using gas chromatography (retention indices and gas chromatography-mass spectrometry while the antimicrobial activities were determinate by paper disc diffusion method and minimum inhibitory concentration assays tested against four bacterial strains and one yeast and antioxidant activity was evaluated as a free radical scavenging capacity (RSC. Results: Essential oils were dominated by non-terpenic compounds and fatty acids. However, the phenylpropanoids, monoterpenes and sesquiterpenes components were only present in small percentages. The most important antibacterial activity of essential oil was expressed on Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Salmonella typhimurium. Antioxidant activity was evaluated as a RSC. RSC was assessed by measuring the scavenging activity of essential oil and ethanol extract on 1,1-diphenyl-2-picrylhydrazil (DPPH. Investigated ethanol extract reduced the DPPH radical formation (IC50=68 µg/mL. Conclusions: Results in this experiment indicate that the essential oil and the ethanol extract display antibacterial activity against two Gram-positive bacteria and activity to a lesser extent against two Gram-negative species. They may be a new potential source of components, which are likely to have impact on human health.

  3. Radical Cations and Acid Protection during Radiolysis

    International Nuclear Information System (INIS)

    Mincher, Bruce J.; Zarzana, Christopher A.; Mezyk, Stephen P.

    2016-01-01

    Ligand molecules for used nuclear fuel separation schemes are exposed to high radiation fields and high concentrations of acid. Thus, an understanding of the complex interactions between extraction ligands, diluent, and acid is critical to understanding the performance of a separation process. The diglycolamides are ligands with important structural similarities to CMPO; however, previous work has shown that their radiolytic degradation has important mechanistic differences from CMPO. The DGAs do not enjoy radioprotection by HNO3 and the kinetics of DGA radiolytic degradation are different. CMPO degrades with pseudo-zero-order kinetics in linear fashion with absorbed dose while the DGAs degrade in pseudo-first-order, exponential fashion. This suggests that the DGAs degrade by simple reaction with some product of direct diluent radiolysis, while CMPO degradation is probably multi-step, with a slow step that is not dependent on the CMPO concentration, and mitigated by HNO 3 . It is thus believed that radio-protection and the zero-order radiolytic degradation kinetics are related, and that these phenomena are a function of either the formation of strong acid complexes with CMPO and/or to the presence of the CMPO phenyl ring. Experiments to test both these hypotheses have been designed and partially conducted. This report summarizes findings related to these phenomena for FY16, in satisfaction of milestone M3FT-16IN030104053. It also reports continued kinetic measurements for the reactions of the dodecane radical cation with solvent extraction ligands.

  4. Radical Cations and Acid Protection during Radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Mincher, Bruce J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zarzana, Christopher A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mezyk, Stephen P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-09

    Ligand molecules for used nuclear fuel separation schemes are exposed to high radiation fields and high concentrations of acid. Thus, an understanding of the complex interactions between extraction ligands, diluent, and acid is critical to understanding the performance of a separation process. The diglycolamides are ligands with important structural similarities to CMPO; however, previous work has shown that their radiolytic degradation has important mechanistic differences from CMPO. The DGAs do not enjoy radioprotection by HNO3 and the kinetics of DGA radiolytic degradation are different. CMPO degrades with pseudo-zero-order kinetics in linear fashion with absorbed dose while the DGAs degrade in pseudo-first-order, exponential fashion. This suggests that the DGAs degrade by simple reaction with some product of direct diluent radiolysis, while CMPO degradation is probably multi-step, with a slow step that is not dependent on the CMPO concentration, and mitigated by HNO3. It is thus believed that radio-protection and the zero-order radiolytic degradation kinetics are related, and that these phenomena are a function of either the formation of strong acid complexes with CMPO and/or to the presence of the CMPO phenyl ring. Experiments to test both these hypotheses have been designed and partially conducted. This report summarizes findings related to these phenomena for FY16, in satisfaction of milestone M3FT-16IN030104053. It also reports continued kinetic measurements for the reactions of the dodecane radical cation with solvent extraction ligands.

  5. "Cartooning capitalism": Radical cartooning and the making of American popular radicalism in the early twentieth century

    OpenAIRE

    Cohen, Michael

    2007-01-01

    During the first two decades of the twentieth century, a mass culture of popular radicalism - consisting of various socialist, industrial unionist, anarchist, Progressive, feminist, black radical and other movements - arose to challenge the legitimacy of corporate capitalism in the United States. This article considers the role of radical cartoonists in propagandizing for, and forging unity within, this culture of popular radicalism. By articulating a common set of anti-capitalist values and ...

  6. Students' Ideas and Radical Constructivism

    Science.gov (United States)

    Sánchez Gómez, Pedro J.

    2016-08-01

    In this article, I study, from the point of view of the analytic philosophy of mind, the compatibility of students' ideas studies (SIS) with radical constructivism (RC). I demonstrate that RC is based on a psychology of narrow mental states; that is, the idea that the mental content of an individual can be fully characterised without any reference external to her or him. I show that this fact imposes some severe restrictions to SIS to be incorporated into RC. In particular, I argue that only qualitative studies can comply with the requirement of narrowness. Nevertheless, I propose that quantitative works can be employed as sources of types in order to study token actual students. I use this type-token dichotomy to put forward an outline of a theory of the relation between school contents and mental contents. In this view, token mental contents regarding a given topic can be defined, and probed, only by resorting to typical school contents.

  7. Iron and iron derived radicals

    Energy Technology Data Exchange (ETDEWEB)

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

  8. Kierkegaard as radical Christian thinker

    Directory of Open Access Journals (Sweden)

    Mojsić Sofija

    2013-01-01

    Full Text Available The main goal of this paper is the reaffirmation and emphasis of the radical, revolutionary aspect of Kierkegaard’s thought which has been mainly neglected in the standard literature on the Danish thinker. The author contends that there were two crises in Kierkegaard’s life: in 1838 and 1848. In 1838 Kierkegaard completely withdrew from the world and people into his “hidden inwardness”, which he claimed to be the essence of true Christianity. In 1848 he broke through his isolation and spoke openly of his new conviction. He stressed the practical and revolutionary character of Christianity, which demanded revolutionary change of the entire society and inner revolution in the individual personality in accordance with the authentic early Christian faith.

  9. Hydroxyl radical formation by dithranol.

    Science.gov (United States)

    Müller, K; Kappus, H

    1988-11-15

    Ethene formation from 2-keto-thiomethyl-butyric acid (KMBA) was used to measure hydroxyl radical generation from the antipsoriatic drug dithranol in phosphate buffer pH 7.8. Because the singlet oxygen (1O2) sensitizer, rose bengale, showed enlarged production of ethene when irradiated in the presence of KMBA, experiments were performed in the dark in order to avoid 1O2 production by dithranol. KMBA was converted to ethene by dithranol under aerobic conditions, whereas ethene formation was negligible in the absence of oxygen. Addition of catalytic amounts of FeCl3 resulted in increased ethene formation, indicating the catalysis of a superoxide-driven Fenton-reaction. O2- - and .OH-scavengers such as rutin, catechin, dimethyl sulfoxide, mannitol, ethanol, sodium salicylate and propyl gallate as well as catalase and superoxide dismutase inhibited ethene formation.

  10. Antioxidant and pro-oxidant effects of green tea extracts in oxygen radical absorbance capacity assay.

    Science.gov (United States)

    Shin, Jung-Keun; Kim, Gyo-Nam; Jang, Hae-Dong

    2007-03-01

    Green tea extracts (GTEs) [water (GTE-W) and 75% ethanol (GTE-E)] were investigated to characterize their propensities to act as antioxidants or as pro-oxidants by analyzing oxygen radical absorbance capacity (ORAC) and scavenging capacity for hydroxyl radical. When 2,2'-azobis(2-amidinopropane) dihydrochloride was used for the generation of peroxyl radicals, both GTE-W and GTE-E exhibited strong concentration-dependent scavenging activity through donating protons, which could be explained by their reducing property. When hydroxyl radicals were generated through the addition of Cu(2+) and H(2)O(2), GTE-W and GTE-E exhibited antioxidant activity or pro-oxidant activity, depending on their concentrations, which might be attributed to the metal chelating activity, the scavenging activity on hydroxyl radical, and/or the pro-oxidant activity to generate some reactive oxygen species. When Cu(2+) without H(2)O(2) was used as an oxidant in the assay, the copper-initiated pro-oxidant activities of GTE-W and GTE-W was consistent with the availability of (-)-epigallocatechin and (-)-epicatechin to generate hydrogen peroxide and/or hydroxyl radical. The pro-oxidant activity of GTE-W and GTE-E was demonstrated by the deoxyribose assay. These results indicate that both GTE-W and GTE-E can have pro-oxidant activity at lower concentrations and antioxidant activity at higher concentrations in the ORAC and deoxyribose assays using generated hydroxyl radicals.

  11. Unified approach to characterization of collisions between reactive radical pairs in solution. Final report

    International Nuclear Information System (INIS)

    Lawler, R.G.

    1986-06-01

    New techniques have been developed for accurately measuring time-dependent EPR spectra of small radicals produced by water radiolysis. These have been applied to the first systematic measurements of spin-lattice relaxation time for small radicals and prove a spin-rotation mechanism for these species. Heisenberg exchange and chemical decay rates for these species, and for the ''stable'' triphenylmethyl radical show that the former process is invariably diffusion controlled even when the latter is not. Initial EPR polarization has been documented for H atoms produced in radiolytic spurs and CIDNP has been detected from HD similarly formed. Both results indicate random spin orientation among initially formed H atoms in water radiolysis. A new mechanism for electron polarization has been discovered. This is a logical consequence of electron spin selective radical recombination and has been documented for sulfite radicals. An anomalous solvent dependence has been discovered for the carbon-13 hyperfine splitting of methyl radicals formed by photolysis of a diacyl peroxide. A technique has been developed for determining both the recombination rate constant and equilibrium association constant simultaneously for strongly associated free radicals using ESR exclusively. The technique has been applied to triphenylmethyl and gives results in good agreement with earlier data obtained by electronic spectroscopy

  12. Modulatory effects of Cassia fistula fruits against free radicals and genotoxicity of mutagens.

    Science.gov (United States)

    Kaur, Sandeep; Kumar, Manish; Kaur, Paramjeet; Kaur, Varinder; Kaur, Satwinderjeet

    2016-12-01

    Cassia fistula L. (Fabaceae) fruits are highly recommended in folklore medicine for curing various ailments. In the current study, methanol (CaFM), hexane (CaFH), chloroform (CaFCl), ethyl acetate (CaFE), butanol (CaFB) and aqueous (CaFA) fractions of C. fistula fruits were investigated for their potential to inhibit the genotoxicity of mutagens and free radicals. The antimutagenicity of fractions was evaluated against the reactive carcinogenic ester generating mutagen, 2-aminofluorene (2-AF) and frame-shift mutation inducing mutagen, 4-nitro-o-phenylenediamine (NPD) in Ames Salmonella typhimurium TA98 tester strain. Among the fractions, CaFE showed strongest protective effect against the mutagenicity of both S9-dependent and direct-acting mutagen with an inhibitory percentage of 81% and 64% at the concentration of 1 × 10 3 and 2.5 × 10 3 respectively. All the fractions were analyzed for free radical scavenging activity using DPPH, nitric oxide, lipid peroxidation and superoxide anion assays. CaFE fraction showed maximum antioxidant activity in comparison to other fractions with an IC 50 of 97.01, 172.36, 144 and 264.79 μg/ml respectively. High performance liquid chromatography showed the presence of catechin, epicatechin and umbelliferone in appreciable amount which may account for its efficacy in combating free radicals and also showed protective effect against the mutagenicity of S9-dependent mutagen, 2-AF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Radical scavenging and anti-inflammatory activity of extracts from Opuntia humifusa Raf.

    Science.gov (United States)

    Cho, Jae Youl; Park, Seung-Chun; Kim, Tae-Wan; Kim, Kil-Soo; Song, Jae-Chan; Kim, Sang-Keun; Lee, Hui-Min; Sung, Hye-Jin; Park, Hwa-Jin; Song, Yong-Beom; Yoo, Eun-Sook; Lee, Choong-Hwan; Rhee, Man-Hee

    2006-01-01

    Opuntia humifusa Raf. (O. humifusa Raf.) is a member of the Cactaceae family. To determine the antioxidative and anti-inflammatory effects of this herb, various solvent fractions (methanol, hexane, chloroform, ethyl acetate, butanol, and water) prepared from the leaves of cacti were tested using DPPH (2,2-diphenyl-l-picrylhydrazyl radical) and xanthine oxidase assays, and nitric oxide (NO)-producing macrophage cells. We found that O. humifusa Raf. displayed potent antioxidative and anti-inflammatory activity. Thus, all solvent fractions, except for the water layer, showed potent scavenging effects. The scavenging effect of the ethyl acetate fraction was higher than that of the other fractions, with IC50 values of 3.6 and 48.2 microg mL(-1). According to activity-guided fractionation, one of the active radical scavenging principles in the ethyl acetate fraction was found to be quercetin. In contrast, only two fractions (chloroform and ethyl acetate) significantly suppressed nitric oxide production from the lipopolysaccharide (LPS)-activated RAW264.7 cells. In addition, chloroform and ethyl acetate fractions significantly blocked the expression of inducible nitric oxide synthetase (iNOS) and interleukin-6 (IL-6) from the RAW264.7 cells stimulated by LPS. Moreover, ethyl acetate fractions significantly blocked the expression of IL-1beta from the RAW264.7 cells stimulated by LPS. Therefore, the results suggested that O. humifusa Raf. may modulate radical-induced toxicity via both direct scavenging activity and the inhibition of reactive species generation, and the modulation of the expression of inflammatory cytokines. Finally, O. humifusa Raf. may be useful as a functional food or drug against reactive species-mediated disease.

  14. Radical Behaviorism and Buddhism: Complementarities and Conflicts

    Science.gov (United States)

    Diller, James W.; Lattal, Kennon A.

    2008-01-01

    Comparisons have been made between Buddhism and the philosophy of science in general, but there have been only a few attempts to draw comparisons directly with the philosophy of radical behaviorism. The present review therefore considers heretofore unconsidered points of comparison between Buddhism and radical behaviorism in terms of their…

  15. Free Radical Mechanisms in Autoxidation Processes.

    Science.gov (United States)

    Simic, Michael G.

    1981-01-01

    Discusses the use of steady-state radiation chemistry and pulse radiolysis for the generation of initial free radicals and formation of peroxy radicals in the autoxidation process. Provides information regarding the autoxidation process. Defines autoxidation reactions and antioxidant action. (CS)

  16. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    B. Mourrain; J.B. Lasserre; M. Laurent (Monique); P. Rostalski; P. Trebuchet (Philippe)

    2013-01-01

    htmlabstractIn this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and

  17. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    B. Mourrain; J.B. Lasserre; M. Laurent (Monique); P. Rostalski; P. Trebuchet (Philippe)

    2011-01-01

    htmlabstractIn this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and

  18. Moment matrices, border bases and radical computation

    NARCIS (Netherlands)

    Lasserre, J.B.; Laurent, M.; Mourrain, B.; Rostalski, P.; Trébuchet, P.

    2013-01-01

    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming its complex (resp. real) variety is finite. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-definite

  19. An Appreciation of Free Radical Chemistry

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 9. An Appreciation of Free Radical Chemistry - 6. Experiments Involving Free Radicals. G Nagendrappa. Classroom Volume 10 Issue 9 September 2005 pp 79-84 ...

  20. EPR spin trapping of protein radicals

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan; Hawkins, Clare Louise

    2004-01-01

    Electron paramagnetic resonance (EPR) spin trapping was originally developed to aid the detection of low-molecular-mass radicals formed in chemical systems. It has subsequently found widespread use in biology and medicine for the direct detection of radical species formed during oxidative stress ...

  1. Resonance raman studies of phenylcyclopropane radical cations

    NARCIS (Netherlands)

    Godbout, J.T.; Zuilhof, H.; Heim, G.; Gould, I.R.; Goodman, J.L.; Dinnocenzo, J.P.; Myers Kelley, A.

    2000-01-01

    Resonance Raman spectra of the radical cations of phenylcyclopropane and trans-1-phenyl-2-methylcyclopropane are reported. A near-UV pump pulse excites a photosensitizer which oxidizes the species of interest, and a visible probe pulse delayed by 35 ns obtains the spectrum of the radical ion. The

  2. Allylthioketone Mediated Free Radical Polymerization of Methacrylates

    Directory of Open Access Journals (Sweden)

    Feng Zhong

    2017-11-01

    Full Text Available By combination of high trapping free radical efficiency of the thioketone and resonance of the allylic radical, a new type of mediating agent, 1,3,3-triphenylprop-2-ene-1-thione (TPPT has been successfully synthesized, and then is used to study controlled free radical polymerization of methacrylates. Very stable TPPT radicals at the end of poly(methyl methacrylate (PMMA are detected in the polymerization of MMA using TPPT and AIBN as the control agent and initiator. The MALDI-TOF MS spectra are used to identify terminal groups of the resultant poly(glycidyl methacrylate (PGMA, and major component of the obtained polymer has the structure, (CH32(CNC-PGMA-C7H9O3. Chain extension reaction tests ascertain formation of the dead polymers during the polymer storage and purification process of the polymers. Owing to very slow fragmentation reaction of the TPPT-terminated polymethacrylate radical and addition reaction of this radical with a primary radical, the growing chain radicals are difficult to be regenerated, leading to an unobvious change of the molecular weight with monomer conversion. The molecular weights of polymers can be controlled by the ratios of monomer/initiator and TPPT/initiator. However, the first order kinetics of the polymerization and the polymers with narrow polydispersity are obtained, and these phenomena are discussed. This study provides useful information on how to design a better controlling agent.

  3. Ideals Adrift: An Educational Approach to Radicalization

    Science.gov (United States)

    van San, Marion; Sieckelinck, Stijn; de Winter, Micha

    2013-01-01

    These days, the radicalization of young people is above all viewed as a security risk. Almost all research into this phenomenon has been carried out from a legal, criminological or socio-psychological perspective with a focus on detecting and containing the risks posed by radicalization. In the light of the political developments since September…

  4. Free radicals in biology. Volume II

    International Nuclear Information System (INIS)

    Pryor, W.A.

    1976-01-01

    This volume continues the treatment of topics in free radical biology and free radical pathology from Volume I. In the first chapter, pyridinyl radicals, radicals which are models for those derived from NAD, are discussed. Pyridinyl radicals can be synthesized and isolated and directly studied in a number of chemical systems. The next chapter treats the role of glutathione in the cell. It is becoming even more apparent that this vital thiol controls a large number of important cellular functions. The GSH/GSSG balance has recently been implicated as a control for cellular development; this balance also may be important in relaying the effects of oxidants from one site to another in the body. The next chapter outlines the reactions of singlet oxygen; some of these involve free radicals and some do not. This reactive intermediate appears to be important both in photochemical smog and in cellular chemistry where singlet oxygen is produced by nonphotochemical processes. The production of free radicals from dry tissues, a controversial area with conflicting claims is reviewed. The next chapter outlines the current status of the studies of photochemical smog. The next two chapters treat specific reactive materials which are present in smog. The first discusses the chemistry of nitrogen oxides and ozone. The second chapter treats the chemistry of the peroxyacyl nitrites. These compounds, although present in only small concentration, are among the most toxic components of smog. The last two chapters treat radiation damage to proteins and radiation protection and radical reactions produced by radiation in nucleic acids

  5. Victimology: A Consideration of the Radical Critique.

    Science.gov (United States)

    Friedrichs, David O.

    1983-01-01

    Discusses the emergence of a new radical model in criminology and a new subdisciplinary area of concern, victimology, with roots in Marx and Engels' original formulations. Argues that the radical understanding of victimization provides an important corrective to mainstream approaches and broadens the focus of the concept of victimization. (JAC)

  6. Studies of a nitroxide radical by EPR in monocrystal: interaction of protons and electronic relaxation

    International Nuclear Information System (INIS)

    Alonso, A.

    1986-01-01

    The ESR spectra of a nitroxide radical, 4-hydroxi-2,2,6,6-tetramethylpiperidine-1-oxyl (TANOL II), introduced as impurity in a diamagnetic host, 4-hydroxi-2,6,6-tetramethylpiperedine (I), were investigated. The use of deuterated radical, 4-hydroxi-2,2,6,6 tetramethylpiperidine-d sub(17) -1, oxyl (PD-TANOL, III) improved the resolution of ESR spectra for most of orientations of magnetic field. The proton interqactions in the neighbourhood of magnetic group N-O were studied and superpyresfine tensors for two strongly coupled protons were determined. In order to study the influence of protons on electronic relaxation of radicals, the relaxation times T sub(1) and T sub(2) were estimated in the temperature range-160 sup(0)C - 25 sup(0)C for several orientations, and comparing data for protonated and deuterated radicals II and III, using the continuous wave saturation method. (author)

  7. Atmospheric chemistry of CF3O radicals: Reaction with H2O

    DEFF Research Database (Denmark)

    Wallington, T.J.; Hurley, M.D.; Schneider, W.F.

    1993-01-01

    Evidence is presented that CF3O radicals react with H2O in the gas phase at 296 K to give CF3OH and OH radicals. This reaction is calculated to be exothermic by 1.7 kcal mol-I implying a surprisingly strong CF3O-H bond energy of 120 +/- 3 kcal mol-1. Results from a relative rate experimental study...... suggest that the rate constant for the reaction of CF3O radicals with H2O lies in the range (0.2-4.0) X 10(-17) cm3 molecule-1 s-1. Implications for the atmospheric chemistry of CF3O radicals are discussed....

  8. Inhibitory effect on nitric oxide production and free radical scavenging activity of Thai medicinal plants in osteoarthritic knee treatment.

    Science.gov (United States)

    Anuthakoengkun, Areeya; Itharat, Arunporn

    2014-08-01

    Thai medicine plants used for Osteoarthritis of knee (OA) treatment consist of twelve plants such as Crinumn asiaticum, Cleome viscosa, Drypetes roxburghii, Piper longum, Piper nigrum, Plumbago indica, Alpinia galanga, Curcuma aromatica, Globba malaccensis, Zingiber montanum, Zingiber officinale andZingiberzerumbet. They showedhighfrequency in OA formula. To investigate inhibitory effect on LPS-induced nitric oxide (NO) release from RAW264. 7 cell and free radical scavenging activity usingDPPH assay of these ethanolic plant extracts. Plant materials were extracted by maceration in 95% ethanol. Anti-inflammatory activity were tested on LPS-induced NO production. Free radical scavenging activity was performed by DPPH assay. All of ethanolic extracts exhibited potent inhibitory effect on NO release. The ethanolic extract of Z. zerumbet exhibited the highest inhibitory effect followed by Z. montanum and G. malaccensis, respectively. Except A. galanga and C. viscosa, all extracts possessed more influential than indomethacin (IC50 = 20.32±3.23 μLg/ml), a positive control. The investigation on antioxidant activity suggested that the ethanolic extracts of D. roxburghii, Z. officinale, Z. montanum, C. aromatic, A. galanga, P indica, G malaccensis, P nigrum exhibited antioxidant activity. By means ofD. roxburghii had the highest electron donating activity,followed by Z. officinale. Moreover both extracts were more effective than BHT apositive control (EC50 = 14.04±1.95 μg/ml). Thai medicinal plants had anti-inflammatory activity and could inhibit destruction of articular cartilage that corresponded to the traditional medicine and supported using these medicinal plants for OA treatment.

  9. Chemical characterization and radical scavenging activity of leaves of Juniperus foetidisima, J. excelsa and J. communis from Macedonian flora

    Directory of Open Access Journals (Sweden)

    Marija Karapandzova

    2014-12-01

    Full Text Available Chemical characterization of three Juniperus species: J. foetidisima (JF, J. excelsa (JE and J. communis (JC from Macedonian flora enclosed determination of yield and essential oil composition of the oils obtained by hydro-distillation of dried leaves and determination of the content of total phenols and total flavonoids in dried plant material. GC/FID/MS analysis showed mainly monoterpene profile of the JC oil and combined monoterpene/sesquiterpene profile of JF and JE oils. Sesquiterpene cedrol was found as an important constituent of the JF and JE, thus the JF oil was characterized by three main components (a-pinene, limonene and cedrol, in amount up to 67.63%, 27.11% and 33.91%, respectively and JE oil by four components (a-pinene, sabinene, cis-thujone and cedrol, in amount up to 33.83%, 29.49%, 26.20% and 24.44%, respectively. The JC oil was free of cedrol, but contained relatively large sesquiterpene fraction (sesquiterpene hydrocarbons and oxygen containing sesquiterpenes in amounts up to 28.64% and 13.57%, respectively. The JC oil was characterized by three monoterpene components (a-pinene, sabinene and terpinen-4-ol, presented up to 28.68%, 16.27% and 12.16%, respectively. The content of total phenols determined by Folin-Ciocalteu method ranged from 96.18-122.91 mg GAE/g dw (water extraction while the content of total flavonoids ranged from 2.05-11.91 mg CE/g dw (ethanol extraction. Both water and ethanol extracts possessed radical scavenging activity against DPPH radical. Water extracts were more powerful with % of inhibition of DPPH ranging up to 64.52%, 67.40% and 78.23% for water extract (10 mg/ml of JF, JE and JC, respectively. Obtained results showed correlation with the content of total phenols.

  10. Electronic structure and properties of hydroxyalkyl radicals

    International Nuclear Information System (INIS)

    Kosobutskij, V.S.; Majboroda, V.D.; Petryaev, E.P.

    1989-01-01

    Quantum-chemical calculation using the MNDo method of hydroxymethyl and hydroxyethyl radicals and corresponding anion-radicals is made. Electron structure of radical particles differs considerably from the structure of initial alcohols. From the viewpoint of perturbation theory of molecular orbitals it is shown that noncoupled electron in hydroxyalkyl radicals and radical-anions occupies the loosening orbital. For this reason the above-mentioned particles easily enter the reactions of electron transfer on the acceptor and are not active in reactions of break-off and addition via binary bond. Theoretical concepts are confirmed by experimental data, obtained when studying gamma-radiolysis of methanol solution in water and in 5M NaOH aqueous solution (dose rate is 0.478 Gy/s, dose range is 0.796-4.293 kGy)

  11. Hydroxyl-radical-induced oxidation of cyclic dipeptides: Reactions of free peptide radicals and their peroxyl radicals

    International Nuclear Information System (INIS)

    Mieden, O.J.

    1989-01-01

    In the course of this study investigations were carried out into the reactions of hydroxyl radicals and hydrogen atoms with cyclic dipeptides as well as the subsequent reactions of peptide radicals and their peroxyl radicals in aqueous solution. The radiolysis products formed in the absence and presence of oxygen or transient metal complexes were characterized and determined on a quantitative basis. The linking of information from product analyses to the kinetic data for transient species obtained by time-resolving UV/VIS and conductivity measurements (pulse radiolysis) as well as computer-assisted simulations of individual events during the reaction permitted an evaluation of the mechanisms underlying the various processes and an identification of interim products with short life-times, which did or did not belong to the group of radicals. Through the characterization of key reactions of radicals and peroxyl radicals of this substance class a major advance has been made towards a better understanding of the role of radicals in the peptide compound and the mechanisms involved in indirect radiation effects on long-chain peptides and proteins. (orig.) [de

  12. An ESR study of radicals induced in irradiated fresh mango

    International Nuclear Information System (INIS)

    Kikuchi, Masahiro; Hussain, Mohammed S.; Morishita, Norio; Kobayashi, Yasuhiko; Ukai, Mitsuko; Shimoyama, Yuhei

    2009-01-01

    An electron spin resonance (ESR) spectroscopic study was performed on the radicals induced irradiated fresh mangoes. Fresh Philippine mangoes were irradiated by the γ-rays, lyophilized and powdered. The ESR spectrum of the dry specimen showed a strong main peak at g=2.004 and a pair of peaks at both magnetic fields of the main peak. The main peak detected from flesh and skin specimens faded away in a few days after the irradiation. On the other hand, the side peaks showed a well-defined dose response even 9 days after the irradiation. The side-peak is a useful mean to define the irradiation on fresh mangoes. (author)

  13. Synchrotron-based valence shell photoionization of CH radical

    Energy Technology Data Exchange (ETDEWEB)

    Gans, B., E-mail: berenger.gans@u-psud.fr, E-mail: christian.alcaraz@u-psud.fr; Falvo, C. [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Holzmeier, F.; Röder, A. [Institut of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg (Germany); Krüger, J.; Garcia, G. A. [Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex (France); Lopes, A.; Alcaraz, C., E-mail: berenger.gans@u-psud.fr, E-mail: christian.alcaraz@u-psud.fr [Laboratoire de Chimie Physique, UMR 8000 CNRS—Univ. Paris-Sud, Univ. Paris-Saclay, Bât. 350, Centre Universitaire Paris-Sud, F-91405 Orsay Cedex (France); Fittschen, C. [Université Lille, CNRS, UMR 8522–PC2A–Physicochimie des Processus de Combustion et de l’Atmosphère, F-59000 Lille (France); Loison, J.-C. [Institut des Sciences Moléculaires, UMR 5255 CNRS—Université de Bordeaux, Bât. A12, 351 cours de la Libération, F-33405 Talence Cedex (France)

    2016-05-28

    We report the first experimental observations of X{sup +} {sup 1}Σ{sup +}←X {sup 2}Π and a{sup +} {sup 3}Π←X {sup 2}Π single-photon ionization transitions of the CH radical performed on the DESIRS beamline at the SOLEIL synchrotron facility. The radical was produced by successive hydrogen-atom abstractions on methane by fluorine atoms in a continuous microwave discharge flow tube. Mass-selected ion yields and photoelectron spectra were recorded as a function of photon energy using a double imaging photoelectron/photoion coincidence spectrometer. The ion yield appears to be strongly affected by vibrational and electronic autoionizations, which allow the observation of high Rydberg states of the neutral species. The photoelectron spectra enable the first direct determinations of the adiabatic ionization potential and the energy of the first triplet state of the cation with respect to its singlet ground state. This work also brings valuable information on the complex electronic structure of the CH radical and its cation and adds new observations to complement our understanding of Rydberg states and autoionization processes.

  14. The Growth of “Islamic” Radical Books in Indonesia

    Directory of Open Access Journals (Sweden)

    Choirul Fuad Yusuf

    2006-02-01

    Full Text Available More recently, at least some decades after the triumph of global communication, thousands of fundamental and radical books—whether politically, religiously or culturally based books—have already rapidly grown in the world-wide. This phenomena, culturally can be seen from the positive spectrum as a new global dynamics of literacy civilization, but on the contrary it also can be considered as any kind of viruses treating the peaceful and harmonious life amongst Muslims' community at large. Even so the growth of religious radical books, including Islamic books which are strongly influenced by the growth and distribution of any universal ideologies and philosophical thoughts. In this concern, this article attempts to explicate of how the exclusive books grew up in Indonesia. A survey on “Mapping of the Islamic Books in the Post-Reformation Era in Indonesia, earned out in 2013 showed us, besides there is an increase of the practical books on Islam read by Muslims at large, the exclusive and extreme books have been growing significantly—including the books published by both fundatnental and radical book publication.

  15. Thermochemical Stability of alpha-Amino-alpha-carbonylmethyl Radicals and Their Resonance As Measured by ESR.

    Science.gov (United States)

    Welle, Frank M.; Beckhaus, Hans-Dieter; Rüchardt, Christoph

    1997-02-07

    ESR spectra of the captodative alpha-amino-alpha-carbonylmethyl radicals 8 have been recorded. No coalescence temperature for the rotation of the two NMe groups was found at temperatures below the decomposition temperature of the radicals. From known coalescence temperatures and rotational barriers of substituted methyl radicals the rotational barrier of >/=17 kcal mol(-)(1) was estimated for the (*)C-N bond in the radicals 8. Enthalpies DeltaH(diss) and entropies DeltaS(diss) of the homolytic dissociation of 7a,c,d into 8a,c,d have been obtained from equilibrium measurements by ESR. By correcting for substituent interaction enthalpies in 7 (steric and geminal), a radical stabilization enthalpy RSE = -20.7 +/- 1.0 kcal mol(-)(1) was obtained for 8. By addition of the known RSEs of dialkylamino- and carbonyl groups, a RSE = -9.9 kcal mol(-)(1) is predicted for 8. The difference between the experimental and predicted values of 10.8 kcal mol(-)(1) is attributed to a synergistic captodative substituent effect. A linear correlation between the radical stabilization enthalpies of the radicals 8 and of other mono- and disubstituted alkyl radicals and their ESR aH(alpha) coupling constants was found. According to this correlation the reduction of aH(alpha) by 1 G corresponds to an increase in RSE of 1.57 kcal mol(-)(1). The large resonance of the captodative alpha-amino-alpha-carbonylmethyl radicals 3, expressed by their high RSE, their small aH(alpha) coupling constant, and their high rotational barrier, can be rationalized by a strong interaction between the alpha-amino and the alpha-carbonyl groups similar to that in amides and expressed in the resonance structures 6.

  16. Fluoropolymer materials and architectures prepared by controlled radical polymerizations

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Jankova Atanasova, Katja; Hvilsted, Søren

    2007-01-01

    This review initially summarizes the mechanisms, merits and limitations of the three controlled radical polymerizations: nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP) or metal catalyzed living radical polymerization, and reversible addition–fragmentation chain...

  17. Involvement of free radicals in breast cancer.

    Science.gov (United States)

    Ríos-Arrabal, Sandra; Artacho-Cordón, Francisco; León, Josefa; Román-Marinetto, Elisa; Del Mar Salinas-Asensio, María; Calvente, Irene; Núñez, Maria Isabel

    2013-08-27

    Researchers have recently shown an increased interest in free radicals and their role in the tumor microenvironment. Free radicals are molecules with high instability and reactivity due to the presence of an odd number of electrons in the outermost orbit of their atoms. Free radicals include reactive oxygen and nitrogen species, which are key players in the initiation and progression of tumor cells and enhance their metastatic potential. In fact, they are now considered a hallmark of cancer. However, both reactive species may contribute to improve the outcomes of radiotherapy in cancer patients. Besides, high levels of reactive oxygen species may be indicators of genotoxic damage in non-irradiated normal tissues. The purpose of this article is to review recent research on free radicals and carcinogenesis in order to understand the pathways that contribute to tumor malignancy. This review outlines the involvement of free radicals in relevant cellular events, including their effects on genetic instability through (growth factors and tumor suppressor genes, their enhancement of mitogenic signals, and their participation in cell remodeling, proliferation, senescence, apoptosis, and autophagy processes; the possible relationship between free radicals and inflammation is also explored. This knowledge is crucial for evaluating the relevance of free radicals as therapeutic targets in cancer.

  18. 'Living'-chain radical polymerisation

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Gennadii V; Marchenko, A P [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2000-05-31

    The review is devoted to various types of compounds used as agents for 'living' radical polymerisation, such as alkoxyamines formed upon addition of the chain carrier radicals, R{sup .}, to stable nitroxyl radicals, as well as products of the addition of the radicals to transition metal complexes with different ligands, etc. In all cases, the mechanism of the action of these agents consists in their reversible dissociation ArightleftarrowsR{sup .} + X{sup .}, where X{sup .} is a stable free radical or a metal-containing complex which can accept radicals R{sup .} (R{sup .} + X{sup .}{yields}A) and thus compete with the quadratic chain termination. Particular attention is paid to the studies which allowed a quantitative formulation of the mechanism of 'living' radical polymerisation in the form of a mathematical model suitable for predicting both the parameters of the polymerisation and the properties of the resulting polymer (molecular mass and polydispersity). The bibliography includes 359 references.

  19. Editorial: From Radicalism to Minority Issues

    Directory of Open Access Journals (Sweden)

    Editor Al-Jami'ah Journal of Islamic Studies

    2014-06-01

    Full Text Available This edition presents contemporary themes around Islam and Muslims in Indonesia from the issues of radicalism, online media, a Dutch scholar during colonial era, women’s resistance to shariatization, local practice of Islamic sufism, minority group, to broader theme of the relation of religion and science. To begin with, James Adam Fenton sheds light on the way in which Indonesian society has responded to radical ideology. He argues that dialogue in open society with democratic spirit helps the society to disengage from radicalism.

  20. User involvement competence for radical innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher

    2007-01-01

    -assisted navigation systems. The case study analysis reveals that firms who closely interact with specific users benefit significantly for their radical innovation work. These users have a high motivation toward new solutions, are open to new technologies, possess diverse competencies, and are embedded into a very......One important market related capability for firms which seek to develop radical innovations is the competence to involve the 'right' users at the 'right' time in the 'right' form. While former studies have identified a rather passive role of users in the radical innovation process, this paper...

  1. Competition of charge- versus radical-directed fragmentation of gas-phase protonated cysteine sulfinyl radicals.

    Science.gov (United States)

    Love, Chasity B; Tan, Lei; Francisco, Joseph S; Xia, Yu

    2013-04-24

    The fragmentation behavior of various cysteine sulfinyl ions (intact, N-acetylated, and O-methylated), new members of the gas-phase amino acid radical ion family, was investigated by low-energy collision-induced dissociation (CID). The dominant fragmentation channel for the protonated cysteine sulfinyl radicals ((SO•)Cys) was the radical-directed Cα-Cβ homolytic cleavage, resulting in the formation of glycyl radical ions and loss of CH2SO. This channel, however, was not observed for protonated N-acetylated cysteine sulfinyl radicals (Ac-(SO•)Cys); instead, charge-directed H2O loss followed immediately by SH loss prevailed. Counterintuitively, the H2O loss did not derive from the carboxyl group but involved the sulfinyl oxygen, a proton, and a Cβ hydrogen atom. Theoretical calculations suggested that N-acetylation significantly increases the barrier (~14 kcal mol(-1)) for the radical-directed fragmentation channel because of its reduced capability to stabilize the thus-formed glycyl radical ions via the captodative effect. N-Acetylation also assists in moving the proton to the sulfinyl site, which reduces the barrier for H2O loss. Our studies demonstrate that for cysteine sulfinyl radical ions, the stability of the product ions (glycyl radical ions) and the location of the charge (proton) can significantly modulate the competition between radical- and charge-directed fragmentation.

  2. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  3. Cultured rat and purified human Pneumocystis carinii stimulate intra- but not extracellular free radical production in human neutrophils

    DEFF Research Database (Denmark)

    Jensen, T; Aliouat, E M; Lundgren, B

    1998-01-01

    The production of free radicals in human neutrophils was studied in both Pneumocystis carinii derived from cultures of L2 rat lung epithelial-like cells and Pneumocystis carinii purified from human lung. Using the cytochrome C technique, which selectively measured extracellular superoxide...... generation, hardly any free radical production was observed after stimulation with cultured rat-derived P. carinii. A chemiluminescence technique, which separately measured intra- and extracellular free radical production, was subsequently employed to differentiate the free radical generation....... It was established that 1) P. carinii stimulated intra- but not extracellular free radical production in human neutrophils, 2) opsonized cultured rat-derived P. carinii stimulated human neutrophils to a strong intracellular response of superoxide production, and 3) opsonized P. carinii, purified from human lung also...

  4. Oxidation of free, peptide and protein tryptophan residues mediated by AAPH-derived free radicals: role of alkoxyl and peroxyl radicals

    DEFF Research Database (Denmark)

    Fuentes-Lemus, E.; Dorta, E.; Escobar, E.

    2016-01-01

    The oxidation of tryptophan (Trp) residues, mediated by peroxyl radicals (ROOc), follows a complex mechanism involving free radical intermediates, and short chain reactions. The reactivity of Trp towards ROOc should be strongly affected by its inclusion in peptides and proteins. To examine...... the latter, we investigated (by fluorescence) the kinetic of the consumption of free, peptide- and protein-Trp residues towards AAPH (2,20 -azobis(2-amidinopropane)dihydrochloride)-derived free radicals. Interestingly, the initial consumption rates (Ri ) were only slightly influenced by the inclusion of Trp...... concentrations (10–50 mM), the values of Ri were nearly constant; and at high Trp concentrations (50 mM to 1 mM), a slower increase of Ri than expected for chain reactions. Similar behavior was detected for all three systems (free Trp, and Trp in peptides and proteins). For the first time we are showing...

  5. Radical Pancreaticoduodenectomy for Benign Disease

    Directory of Open Access Journals (Sweden)

    D. O. Kavanagh

    2008-01-01

    Full Text Available Whipple's procedure is the treatment of choice for pancreatic and periampullary malignancies. Preoperative histological confirmation of malignancy is frequently unavailable and some patients will subsequently be found to have benign disease. Here, we review our experience with Whipple's procedure for patients ultimately proven to have benign disease. The medical records of all patients who underwent Whipple's procedure during a 15-year period (1987–2002 were reviewed; 112 patients underwent the procedure for suspected malignancy. In eight cases, the final histology was benign (7.1%. One additional patient was known to have benign disease at resection. The mean age was 50 years (range: 30–75. The major presenting features included jaundice (five, pain (two, gastric outlet obstruction (one, and recurrent gastrointestinal haemorrhage (one. Investigations included ultrasound (eight, computerised tomography (eight, endoscopic retrograde cholangiopancreatography (seven; of these, four patients had a stent inserted and three patients had sampling for cytology, and endoscopic ultrasound (two. The pathological diagnosis included benign biliary stricture (two, chronic pancreatitis (two, choledochal cyst (one, inflammatory pseudotumour (one, cystic duodenal wall dysplasia (one, duodenal angiodysplasia (one, and granular cell neoplasm (one. There was no operative mortality. Morbidity included intra-abdominal collection (one, anastomotic leak (one, liver abscess (one, and myocardial infarction (one. All patients remain alive and well at mean follow-up of 41 months. Despite recent advances in diagnostic imaging, 8% of the patients undergoing Whipple'’s procedure had benign disease. A range of unusual pathological entities can mimic malignancy. Accurate preoperative histological diagnosis may have allowed a less radical operation to be performed. Endoscopic ultrasound–guided fine needle aspirate (EUS-FNA may reduce the need for Whipple's operation in

  6. Radical pancreaticoduodenectomy for benign disease.

    LENUS (Irish Health Repository)

    Kavanagh, D O

    2008-01-01

    Whipple\\'s procedure is the treatment of choice for pancreatic and periampullary malignancies. Preoperative histological confirmation of malignancy is frequently unavailable and some patients will subsequently be found to have benign disease. Here, we review our experience with Whipple\\'s procedure for patients ultimately proven to have benign disease. The medical records of all patients who underwent Whipple\\'s procedure during a 15-year period (1987-2002) were reviewed; 112 patients underwent the procedure for suspected malignancy. In eight cases, the final histology was benign (7.1%). One additional patient was known to have benign disease at resection. The mean age was 50 years (range: 30-75). The major presenting features included jaundice (five), pain (two), gastric outlet obstruction (one), and recurrent gastrointestinal haemorrhage (one). Investigations included ultrasound (eight), computerised tomography (eight), endoscopic retrograde cholangiopancreatography (seven; of these, four patients had a stent inserted and three patients had sampling for cytology), and endoscopic ultrasound (two). The pathological diagnosis included benign biliary stricture (two), chronic pancreatitis (two), choledochal cyst (one), inflammatory pseudotumour (one), cystic duodenal wall dysplasia (one), duodenal angiodysplasia (one), and granular cell neoplasm (one). There was no operative mortality. Morbidity included intra-abdominal collection (one), anastomotic leak (one), liver abscess (one), and myocardial infarction (one). All patients remain alive and well at mean follow-up of 41 months. Despite recent advances in diagnostic imaging, 8% of the patients undergoing Whipple\\'s procedure had benign disease. A range of unusual pathological entities can mimic malignancy. Accurate preoperative histological diagnosis may have allowed a less radical operation to be performed. Endoscopic ultrasound-guided fine needle aspirate (EUS-FNA) may reduce the need for Whipple\\'s operation

  7. Day case laparoscopic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Hamid Abboudi

    2017-10-01

    Full Text Available Background: To evaluate the feasibility of performing laparoscopic radical prostatectomy (LRP as a day case procedure while maintaining patient satisfaction and safety. Herein we report our experience, selection criteria, and discharge criteria for day case LRP. Methods: We performed a prospective study with 32 patients undergoing extraperitoneal LRP. These patients were counselled before the procedure that they would go home the same evening of the procedure. Pain scores and quality of life data were recorded day 1 postoperatively via a telephone consultation. The patients underwent routine blood tests on day 2 and an outpatient review on day 7 and regularly thereafter via an assigned key worker. Socio-demographic data, comorbidities, and outcomes were collected for analysis. Results: All patients were successfully discharged the same day of surgery. Mean patient age was 62 years with a mean body mass index of 25. Mean operative time was 147 minutes, and estimated blood loss was 101 ml. Three patients were treated for post operative urinary tract infections; two patients developed infected lymphoceles which required percutaneous drainage and one patient required re-catheterisation due to a burst catheter balloon. Of these six complications four patients required re-admission. Post-operative pain, nausea and vomiting were low whilst patient satisfaction scores were unanimously high in all patients surveyed. Conclusions: The early experience with extraperitoneal LRP as a same day surgery is promising although patients who are at high risk of lymphocele should be excluded. Preoperative patient counselling and selection is paramount. Patient satisfaction is not adversely affected by the shortened stay. Surgeon experience, a well-motivated patient, meticulous attention to detail through an integrated pathway, a multidisciplinary team and adequate postoperative assessment are essential.

  8. Fast Identification of Radical Scavengers from Securigera varia by Combining 13C-NMR-Based Dereplication to Bioactivity-Guided Fractionation.

    Science.gov (United States)

    Sientzoff, Pacôme; Hubert, Jane; Janin, Coralie; Voutquenne-Nazabadioko, Laurence; Renault, Jean-Hugues; Nuzillard, Jean-Marc; Harakat, Dominique; Magid, Abdulmagid Alabdul

    2015-08-14

    Securigera varia (Fabaceae) is a common herbaceous perennial plant widely growing in Europe and Asia and purposely established for erosion control, roadside planting, and soil rehabilitation. The aim of this study was to determine the radical scavenging activity of a crude methanol extract of S. varia aerial parts by using the free radical DPPH (1,1-diphenyl-2-picrylhydrazyl) and to rapidly identify the compounds involved in this activity. The crude extract was initially separated in five fractions on Diaion HP20 resin and the most active part was fractionated by Centrifugal Partition Extraction (CPE). Known compounds were directly identified by a (13)C-NMR-based dereplication method. Semi-preparative high performance liquid chromatography purification experiments were further performed to identify unknown or minor active compounds. As a result, one new (13) and twelve known flavonoid glycosides together with three nitropropanoylglucopyranoses were isolated, including astragalin (1), kaempferol-3-O-(6-O-acetyl)-β-D-glucopyranoside (2), kaempferol-3,4'-di-O-β-D-glucopyranoside (3), trifolin (4), isoquercitrin (5), hyperoside (6), isovitexin (7), isoorientin (8), isovitexin 4'-O-β-D-glucopyranoside (9), apigenin 7-O-β-D-glucuronopyranoside (10), luteolin 7-O-β-D-glucuronopyranoside (11), apigenin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucuronopyranoside (12), apigenin 7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (13), 6-O-(3-nitropropanoyl)-β-D-glucopyranoside (14), coronillin (16) and coronarian (15). 120 mg of the most active compound isoorientin against the free radical DPPH was recovered by CPE with an HPLC purity of 99%.

  9. Fast Identification of Radical Scavengers from Securigera varia by Combining 13C-NMR-Based Dereplication to Bioactivity-Guided Fractionation

    Directory of Open Access Journals (Sweden)

    Pacôme Sientzoff

    2015-08-01

    Full Text Available Securigera varia (Fabaceae is a common herbaceous perennial plant widely growing in Europe and Asia and purposely established for erosion control, roadside planting, and soil rehabilitation. The aim of this study was to determine the radical scavenging activity of a crude methanol extract of S. varia aerial parts by using the free radical DPPH (1,1-diphenyl-2-picrylhydrazyl and to rapidly identify the compounds involved in this activity. The crude extract was initially separated in five fractions on Diaion HP20 resin and the most active part was fractionated by Centrifugal Partition Extraction (CPE. Known compounds were directly identified by a 13C-NMR-based dereplication method. Semi-preparative high performance liquid chromatography purification experiments were further performed to identify unknown or minor active compounds. As a result, one new (13 and twelve known flavonoid glycosides together with three nitropropanoylglucopyranoses were isolated, including astragalin (1, kaempferol-3-O-(6-O-acetyl-β-D-glucopyranoside (2, kaempferol-3,4′-di-O-β-D-glucopyranoside (3, trifolin (4, isoquercitrin (5, hyperoside (6, isovitexin (7, isoorientin (8, isovitexin 4′-O-β-D-glucopyranoside (9, apigenin 7-O-β-D-glucuronopyranoside (10, luteolin 7-O-β-D-glucuronopyranoside (11, apigenin 7-O-α-L-rhamnopyranosyl-(1→2-β-D-glucuronopyranoside (12, apigenin 7-O-β-D-glucopyranosyl-(1→2-β-D-glucuronopyranoside (13, 6-O-(3-nitropropanoyl-β-D-glucopyranoside (14, coronillin (16 and coronarian (15. 120 mg of the most active compound isoorientin against the free radical DPPH was recovered by CPE with an HPLC purity of 99%.

  10. Through-bond interaction in the radical cation of N,N-dimethylpiperazine

    DEFF Research Database (Denmark)

    Brouwer, A.M.; Langkilde, F.W.; Bajdor, K.

    1994-01-01

    The radical cation of N,N-dimethylpiperazine is investigated by resonance Raman spectroscopy and ab initio calculations. The calculations strongly support the assignment of the vibrational spectrum to a chair conformation. It is shown that a dramatic geometry relaxation following ionization allow...... a much more efficient interaction between the nitrogen 'lone pairs' than in the neutral ground state....

  11. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R

    1998-12-14

    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  12. Psychopathology according to behaviorism: a radical restatement.

    Science.gov (United States)

    Pérez-Alvarez, Marino

    2004-11-01

    This article is a radical restatement of the predominant psychopathology, which is characterized by nosological systems and by its approach towards a neurobiological conception of the so-called mental disorders. The "radical" sense of this restatement is that of radical behaviorism itself. As readers will recall, "radical" applied to behaviorism means total (not ignoring anything that interests psychology), pragmatic (referring to the practical sense of knowledge), and it also derives from the Latin word for "root" (and thus implies change beginning at a system's roots or getting to the root of things, in this case, of psychological disorders). Based on this, I introduce the Aristotelian distinction of material and form, which, besides being behaviorist avant la lettre, is used here as a critical instrument to unmask the hoax of psychopathology as it is presented. The implications of this restatement are discussed, some of them already prepared for clinical practice.

  13. Interactions between simple radicals and water

    International Nuclear Information System (INIS)

    Crespo-Otero, Rachel; Sanchez-Garcia, Elsa; Suardiaz, Reynier; Montero, Luis A.; Sander, Wolfram

    2008-01-01

    The interactions of the simple radicals CH 3 , NH 2 , OH, and F with water have been studied by DFT (UB3LYP/6-311++G(2d,2p)) and ab initio (RHF-UCCSD(T)/6-311++G(2d,2p)) methods. In this order the number of lone pairs (from zero to three), the electronegativity, and the strength of the X-H bonds increase (X = C, N, and O). The various minima of the radical-water complexes were located using the multiple minima hypersurface (MMH) approach which had previously been proven to be useful for closed-shell molecules. The role of the unpaired electron in hydrogen bonding was investigated using the natural bond orbital (NBO) analysis. A considerable contribution of the unpaired electron to the complex stabilization was only found for the methyl radical and the fluorine atom, whereas in the aminyl and the hydroxyl radical the role of the unpaired electron is negligible

  14. Photodynamically generated bovine serum albumin radicals

    DEFF Research Database (Denmark)

    Silvester, J A; Timmins, G S; Davies, Michael Jonathan

    1998-01-01

    Porphyrin-sensitized photoxidation of bovine serum albumin (BSA) results in oxidation of the protein at (at least) two different, specific sites: the Cys-34 residue giving rise to a thiyl radical (RS.); and one or both of the tryptophan residues (Trp-134 and Trp-214) resulting in the formation...... of tertiary carbon-centred radicals and disruption of the tryptophan ring system. In the case of porphyrins such as hematoporphyrin, which bind at specific sites on BSA, these species appear to arise via long-range transfer of damage within the protein structure, as the binding site is some distance from...... the ultimate site of radical formation. This transfer of damage is shown to depend on a number of factors including the conformation of the protein, the presence of blocking groups and pH. Alteration of the protein conformation results in radical formation at additional (or alternative) sites, as does blocking...

  15. Radicalization and the Use of Social Media

    Directory of Open Access Journals (Sweden)

    Robin Thompson

    2011-01-01

    Full Text Available The use of social media tools by individuals and organizations to radicalize individuals for political and social change has become increasingly popular as the Internet penetrates more of the world and mobile computing devices are more accessible. To establish a construct for radicalization,the power and reach of social media will be described so there is common understanding of what social media is and how it is utilized by various individuals and groups. The second section will answer the question of why social media applications are the perfect platform for the radical voice. Finally, the use of social media and its influence in radicalizing populations in Northern Africa and the Middle East during 2011 will be analyzed and recommendations proposed.

  16. Radical Sustainable Innovation of office buildings

    DEFF Research Database (Denmark)

    Koch, Christian; Berker, Thomas; Koch-Ørvad, Nina

    2017-01-01

    by high degrees of newness in the entire life cycle. RSI should offer significant enhancements of known benefits, entirely new benefits, or substantial cost reductions, leading to the transformation of existing markets, the creation of sustainable growth, and global sustainability. Thus, if buildings were......The recent development of technologies, processes and methods of sustainable building has enabled an unprecedented quantum leap in the available solutions. These possibilities could be interpreted as radical, yet they appear at a time as results of a long emergent development. The aim of this paper...... is to critically scrutinize, theoretically and empirically, whether radical innovation is occurring in sustainable building and what the implication are. The theoretical framework is based on concepts of radical innovation, inventions and sustainability. Radical sustainable innovation (RSI) should be characterized...

  17. Prison Radicalization: The New Extremist Training Grounds?

    National Research Council Canada - National Science Library

    Coffin, Jr., McKinley D

    2007-01-01

    As a nation with the largest prison population in the world, the United States has all the ingredients for criminals, extremists, and religious radicals to collaborate in producing a new breed of homegrown terrorist...

  18. Sphingomyelinase inhibitory and free radical scavenging potential ...

    African Journals Online (AJOL)

    Sphingomyelinase inhibitory and free radical scavenging potential of selected Nigerian medicinal plant extracts. FM Awah, PN Uzoegwu, P Ifeonu, JO Oyugi, J Rutherford, X Yao, F Fehrmann, KR Fowke, MO Eze ...

  19. Free radical scavenging activity of papaya juice

    Energy Technology Data Exchange (ETDEWEB)

    Webman, E.J.; Mower, H.F.; Edlin, Gordon

    1989-03-01

    Papaya juice is an efficient scavenger of highly reactive hydroxyl radicals (OH radical) formed during /sup 60/Co irradiation of water. The OH anion radicals were detected by the electron spin resonance (ESR) technique of spin trapping using DMPO (5,5-dimethyl-1-pyrroline-N-oxide) or by a colorimetric assay in which salicylate is converted into polyhydroxybenzoic acids. Papaya juice is also able to quench the ESR signal of a stable free radical (TEMPOL) and the ESR signal of the DMPO-OH adduct. The active substance(s) in papaya juice are heat-stable, dialyzable, and soluble in water but not in lipid solvents. The active agents do not appear to be ascorbate, tocopherol, or carotenoids.

  20. ESR of radicals captured in coal

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y.; Yamakawa, T.

    1986-01-01

    A study is reported of the interrelation between the state of movement exhibited by a spin probe radical added to Morwell, Wandoan and Liddell coals, and 1) the pore structure of the coals, 2) the configuration of their functional groups. The radicals used as the spin probe was 2,2,6,6-tetramethyl-4-piperidinol-1-oxyl (TEMPOL). In the case of Wandoan coal, the probe radical entered the pores, with the result that the degree of freedom of its rotational movement remained restricted up to high temperatures. With Liddell coal, the shift to free rotation took place over a broader range of temperatures. This was due to the distribution of active sites where interaction with the introduced radical molecules was possible. 14 references, 6 figures, 3 tables.

  1. Proton hyperfine tensors in nitroxide radicals

    Energy Technology Data Exchange (ETDEWEB)

    Brustolon, M.; Maniero, A.L.; Segre, U. (Universita di Padova (Italy)); Ottaviani, M.F. (Universita di Firenze (Italy)); Romanelli, M. (Universita della Basilicata (Italy))

    1990-08-23

    The proton hyperfine tensors of five nitroxide radicals have been obtained by ENDOR spectroscopy in frozen solution. The spectra are interpreted by computing the dipolar hyperfine interaction and simulating the spectra. EPR spectra in solution of the same radicals have been simulated by taking into account the effects of the proton hyperfine tensors. We have been able to reproduce accurately the line broadening effects of the proton hyperfine structures inside each nitrogen hyperfine component and we have determined the correlation times for the rotational motion. In the case of the radical Tempol, our analysis allows discrimination between the effects due to the protons of the axial and equatorial methyl groups. On the basis of experimental evidence we can attribute the larger isotropic hyperfine coupling constant to the axial methyl protons. The possible use of the present results for interpreting the spectra of other nitroxide radicals is discussed.

  2. Neo-liberal Governing of 'Radicals'

    DEFF Research Database (Denmark)

    Lindekilde, Lasse

    2012-01-01

    The Danish government’s counter-radicalization Action Plan of 2009 had intended and unintended effects. Primarily targeting Danish Muslims, it employs neoliberal governmentality approaches of governance through individual support and response, information and knowledge, empowerment, surveillance...

  3. Fast beam studies of free radical photodissociation

    Energy Technology Data Exchange (ETDEWEB)

    Neumark, D.M. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    The authors have developed a novel technique for studying the photodissociation spectroscopy and dynamics of free radicals. In these experiments, radicals are generated by laser photodetachment of a fast (6-8 keV) mass-selected negative ion beam. The resulting radicals are photodissociated with a second laser, and the photofragments are collected and detected with high efficiency using a microchannel plate detector. The overall process is: ABC{sup -} {yields} ABC + e{sup -} {yields} A + BC, AB + C. Two types of fragment detection schemes are used. To map out the photodissociation cross-section of the radical, the photodissociation laser is scanned and the total photofragment yield is measured as a function of wavelength. In other experiments, the photodissociation frequency is fixed and the photofragment masses, kinetic energy release, and scattering angle is determined for each photodissociation event.

  4. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  5. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  6. Measurement of peroxy radicals by chemical ionization mass spectrometry with a corona ion source

    Science.gov (United States)

    Wang, Weihao; Tham, Yee Jun; Wang, Zhe; Tanner, David; Yu, Chuan; Wang, Tao

    2017-04-01

    Peroxy radicals including hydroperoxyl (HO2) and organic peroxy (RO2) radicals play key roles in atmospheric radical chemistry. However, accurate measurement of these radicals remains a challenge due to low concentration, strong activity and not well known intereference. Here we present the measurement of ambient peroxy (HO2+RO2) radicals at an urban site in Hong Kong using chemical ionization mass spectrometry (CIMS) with a corona ion source. The peroxy radicals are titrated by NO into OH and further converted into H2SO4, which is detected by the CIMS through the reaction with NO3- ions. Although the corona ion source has advantages as a non-radiative source and with a low cost, it has a higher background and is less stable compared to the widely used radioactive source. We have improved the design of the corona ion source. The detection limit for the corona ion source is 1×108 molecules/cm3 for an integration time of 1 min. Hexafluoropropylene (C3F6), which is widely used as OH scavenger, has been shown to produce HO2 through its reaction with OH in presence of high concentrations of NO, leading to high instrument background for HO2. The measurement results of ambient HO2 and RO2 during a photochemical episode will be presented.

  7. Structure reactivity relationship in the reaction of DNA guanyl radicals with hydroxybenzoates

    Energy Technology Data Exchange (ETDEWEB)

    Do, Trinh T.; Tang, Vicky J.; Aguilera, Joseph A. [Department of Radiology University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States); Milligan, Jamie R., E-mail: jmilligan@ucsd.ed [Department of Radiology University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0610 (United States)

    2010-11-15

    In DNA, guanine bases are the sites from which electrons are most easily removed. As a result of hole migration to this stable location on guanine, guanyl radicals are major intermediates in DNA damage produced by the direct effect of ionizing radiation (ionization of the DNA itself and not through the intermediacy of water radicals). We have modeled this process by employing gamma irradiation in the presence of thiocyanate ions, a method which also produces single electron oxidized guanyl radicals in plasmid DNA in aqueous solution. The stable products formed in DNA from these radicals are detected as strand breaks after incubation with the FPG protein. When a phenolic compound is present in the solution during gamma irradiation, the formation of guanyl radical species is decreased by electron donation from the phenol to the guanyl radical. We have quantified the rate of this reaction for four different phenolic compounds bearing carboxylate substituents as proton acceptors. A comparison of the rates of these reactions with the redox strengths of the phenolic compounds reveals that salicylate reacts ca. 10-fold faster than its structural analogs. This observation is consistent with a reaction mechanism involving a proton coupled electron transfer, because intra-molecular transfer of a proton from the phenolic hydroxyl group to the carboxylate group is possible only in salicylate, and is favored by the strong 6-membered ring intra-molecular hydrogen bond in this compound.

  8. Detection and Quantification of Free Radicals in Peroxisomal Disorders: A Comparative Study with Oxidative Stress Parameters.

    Science.gov (United States)

    Abd-Elmaksoud, Sohair Abd-El Mawgood; El-Bassyouni, Hala; Afifi, Hanan; Thomas, Manal Micheal; Ibrahim, Alshaymaa Ahmed; Shalaby, Aliaa; Hamid, Tamer Ahmed Abdel; Hamid, Nehal Abdel; El-Ghobary, Hany

    2015-11-01

    Free radicals have been thought to participate in pathogenesis of peroxisomal disorders. The aim of the work is to detect free oxide radicals in blood of patients with peroxisomal disorders and to study their relation with various oxidative stress parameters. Twenty patients with peroxisomal disorders and 14 age and sex matched healthy subjects were included in the study. Patients with peroxisomal disorders were subdivided according to diagnosis into peroxisomal biogenesis disorders and single enzyme deficiency. Oxidative stress was evaluated in both patients and control subjects by assessment of free radicals, malondialdehyde, nitric oxide metabolites and superoxide dismutase. There was increase in free radicals, malondialdehyde, nitric oxide metabolites in patients compared with control subjects. However, there was decrease in superoxide dismutase levels in patients compared with control subjects. We concluded that there is excess free radicals production accompanied with decrease in antioxidant defenses in patients with peroxisomal disorders. These results strongly support a role of free radicals in the pathophysiology of peroxisomal disorders and strengthen the importance of oxidative stress phenomenon in peroxisomal disorders pathogenesis.

  9. The Radical Flank Effect and Cross-occupational Collaboration for Technology Development during a Power Shift.

    Science.gov (United States)

    Truelove, Emily; Kellogg, Katherine C

    2016-12-01

    This 12-month ethnographic study of an early entrant into the U.S. car-sharing industry demonstrates that when an organization shifts its focus from developing radical new technology to incrementally improving this technology, the shift may spark an internal power struggle between the dominant engineering group and a challenger occupational group such as the marketing group. Analyzing 42 projects in two time periods that required collaboration between engineering and marketing during such a shift, we show how cross-occupational collaboration under these conditions can be facilitated by a radical flank threat, through which the bargaining power of moderates is strengthened by the presence of a more-radical group. In the face of a strong threat by radical members of a challenger occupational group, moderate members of the dominant engineering group may change their perceptions of their power to resist challengers' demands and begin to distinguish between the goals of radical versus more-moderate challengers. To maintain as much power as possible and prevent the more-dramatic change in engineering occupational goals demanded by radical challengers, moderate engineers may build a coalition with moderate challengers and collaborate for incremental technology development.

  10. Glutathione radical cation in the gas phase; generation, structure and fragmentation.

    Science.gov (United States)

    Zhao, Junfang; Siu, K W Michael; Hopkinson, Alan C

    2011-11-07

    Two different chemical methods have been used to form glutathione radical cations: (1) collision-induced dissociations (CIDs) of the ternary complex [Cu(II)(tpy)(M)]˙(2+) (M = GSH, tpy = 2,2':6',2''-terpyridine) and (2) homolysis of the S-NO bond in protonated S-nitrosoglutathione. The radical cations, M˙(+), were trapped and additional CIDs were performed. They gave virtually identical CID spectra, suggesting a facile interconversion between initial structures prior to fragmentation. DFT calculations at the B3LYP/6-31++G(d,p) level of theory have been used to study interconversion between different isomers of the glutathione radical cation and to examine mechanisms by which these ions fragment. The N-terminal α-carbon-centred radical cation, strongly stabilized by the captodative effect, is at the global minimum, which is 8.5 kcal mol(-1) lower in enthalpy than the lowest energy conformer of the S-centred radical cation. The barrier against interconversion is 18.1 kcal mol(-1) above the S-centred radical.

  11. Analysis of radicals of irradiated garlic

    International Nuclear Information System (INIS)

    Kameya, Hiromi; Kaimori, Yoshihiko; Ukai, Mitsuko

    2010-01-01

    The detection method of gamma ray irradiated garlic using Electron Spin Resonance(ESR)spectroscopy was studied. The ESR spectrum was consisted of one singlet signal at g=2.00. This signal is due to an organic free radical. Upon irradiation, the intensity of the signal was increased. Also two signals due to cellulose radical were detected nearby the singlet. The intensity of the singlet signal was increased as depend on the increase of the irradiation dose level. (author)

  12. [Early complications following open radical prostatectomy

    DEFF Research Database (Denmark)

    Roder, M.A.; Gruschy, L.; Brasso, K.

    2009-01-01

    INTRODUCTION: Radical prostatectomy has been offered as curative treatment for localized prostate cancer at Rigshospitalet since August 1995. We here report on postoperative complications in 719 patients operated during the 12-year-period from August 1995 to August 2007 with special emphasis...... patients (1,1%). One patient died within 30 days after surgery. CONCLUSION: Our results demonstrate that radical prostatectomy can be performed with a minimal mortality and an acceptable morbidity Udgivelsesdato: 2009/4/27...

  13. Inactivation of Bacillus atrophaeus by OH radicals

    Science.gov (United States)

    Ono, Ryo; Yonetamari, Kenta; Tokumitsu, Yusuke; Yonemori, Seiya; Yasuda, Hachiro; Mizuno, Akira

    2016-08-01

    The inactivation of Bacillus atrophaeus by OH radicals is measured. This study aims to evaluate the bactericidal effects of OH radicals produced by atmospheric-pressure nonthermal plasma widely used for plasma medicine; however, in this study, OH radicals are produced by vacuum ultraviolet (VUV) photolysis of water vapor instead of plasma to allow the production of OH radicals with almost no other reactive species. A 172 nm VUV light from a Xe2 excimer lamp irradiates a He-H2O mixture flowing in a quartz tube to photodissociate H2O to produce OH, H, O, HO2, H2O2, and O3. The produced reactive oxygen species (ROS) flow out of the quartz tube nozzle to the bacteria on an agar plate and cause inactivation. The inactivation by OH radicals among the six ROS is observed by properly setting the experimental conditions with the help of simulations calculating the ROS densities. A 30 s treatment with approximately 0.1 ppm OH radicals causes visible inactivation.

  14. Deceleration of molecular beams of NO radicals

    Energy Technology Data Exchange (ETDEWEB)

    Klenner, Alexander; Kirste, Moritz; Schewe, Christian; Scharfenberg, Ludwig; Meijer, Gerard; Meerakker, Sebastian Y.T. van de [Fritz-Haber-Institut, Max-Planck-Gesellschaft, Berlin (Germany)

    2010-07-01

    The motion of neutral molecules in a beam can be manipulated with inhomogeneous electric and magnetic fields. Time-varying fields can be used to decelerate or accelerate beams of molecules to any desired velocity. Molecular beams with a tunable velocity find applications in experiments such as the production and investigation of cold molecules or crossed beam collision studies. Molecules with an open shell structure like the OH(X2{pi}3/2,J=3/2) radical are of special interest and have often been used. The NO (X2{pi}1/2,J=1/2) radical would be the ideal molecule in these experiments, as beams of NO can be produced with superior number densities and can be detected more sensitively than OH. But Stark deceleration of NO radicals appears only feasible in the X2{pi}3/2,J=3/2 state, that is not populated under normal conditions. We present the production of intense beams of NO radicals in the X2{pi}3/2,J=3/2 state by stimulated emission pumping of ground-state NO(X2{pi}1/2,J=1/2) radicals via the A 2{sigma}{sup -} state. This state also has a large magnetic dipole moment, and we discuss the prospects for the Zeeman deceleration of NO(X2{pi}3/2,J=3/2) radicals.

  15. Radical and Not So Radical Transgressions: Invading Backstage Domains

    Directory of Open Access Journals (Sweden)

    Lada Čale Feldman

    2012-06-01

    Full Text Available Featuring as one of the privileged metaphors in humanities and social sciences, theatre provides primarily an image of a circumscribed space whose spatial syntax and modes of human engagement take place within and with respect to the larger space of the city, the world, and, as in Calderon’s Gran teatro del mundo, the universe. It is precisely as a special organization of spatiality that theatre reached the status of Foucault’s radical hetero-topos, flexible as it proved to be as a model for not only counter-representing all the human dealings in the external space, but also of conceptualizing, as in Freud’s psychoanalysis, man’s inner world, his psychic topography. But theatre is above all a concrete place, a built form with its own spatial history, its changing social and ideological functions, and its ways of bestowing to the bodies that enter into it actual or phantasm identities, thoughts, sensations, feelings and memories.My intervention will deal with one of the ruling borders/dichotomies/barriers of theatrical space, the one dividing “front stage” from “backstage” regions. In his detailed analysis of the latter in an individual and concrete theatre building, Andrew Filmer relies among others on Edward Soja’s “trialectics of being”, and thus also on Lefebvre’s categories of perceptual, conceptual and lived aspects of spatiality which Soja evokes, which will here be of particular interest. In contrast to the repercussions of such an analytical triad for the ethnographic study of concrete theatrical sites, I will ask how it pertains to potential manipulations of the aforementioned division of front-stage and backstage within contemporary performance practice. The temporal aspect of this manipulation should also be emphasized, having in mind the historical provenance of a whole backstage mythology – evidenced in numerous novels, plays and films situated in the backstage world - in the elaborated architectural

  16. Titanium: light, strong, and white

    Science.gov (United States)

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  17. Free radical scavenging activities of pigment extract from Hibiscus ...

    African Journals Online (AJOL)

    AJL

    2012-01-05

    Jan 5, 2012 ... 2008; Perry et al., 2000). In living organism, free radicals including hydroxyl radical, superoxide anion radical, peroxide radical are generated as the medium of energy supply, detoxification, chemical signal and immunity. But during the excessive metabolism, they cause extensive oxidative damage to cells ...

  18. Streptomyces sp. MUM212 as a Source of Antioxidants with Radical Scavenging and Metal Chelating Properties

    Directory of Open Access Journals (Sweden)

    Loh Teng-Hern Tan

    2017-05-01

    Full Text Available Reactive oxygen species and other radicals potentially cause oxidative damage to proteins, lipids, and DNA which may ultimately lead to various complications including mutations, carcinogenesis, neurodegeneration, cardiovascular disease, aging, and inflammatory disease. Recent reports demonstrate that Streptomyces bacteria produce metabolites with potent antioxidant activity that may be developed into therapeutic drugs to combat oxidative stress. This study shows that Streptomyces sp. MUM212 which was isolated from mangrove soil in Kuala Selangor, Malaysia, could be a potential source of antioxidants. Strain MUM212 was characterized and determined as belonging to the genus Streptomyces using 16S rRNA gene phylogenetic analysis. The MUM212 extract demonstrated significant antioxidant activity through DPPH, ABTS and superoxide radical scavenging assays and also metal-chelating activity of 22.03 ± 3.01%, 61.52 ± 3.13%, 37.47 ± 1.79%, and 41.98 ± 0.73% at 4 mg/mL, respectively. Moreover, MUM212 extract was demonstrated to inhibit lipid peroxidation up to 16.72 ± 2.64% at 4 mg/mL and restore survival of Vero cells from H2O2-induced oxidative damages. The antioxidant activities from the MUM212 extract correlated well with its total phenolic contents; and this in turn was in keeping with the gas chromatography–mass spectrometry analysis which revealed the presence of phenolic compounds that could be responsible for the antioxidant properties of the extract. Other chemical constituents detected included hydrocarbons, alcohols and cyclic dipeptides which may have contributed to the overall antioxidant capacity of MUM212 extract. As a whole, strain MUM212 seems to have potential as a promising source of novel molecules for future development of antioxidative therapeutic agents against oxidative stress-related diseases.

  19. Composition, antimicrobial and free-radical scavenging activities of the essential oil of Plectranthus marrubatus.

    Science.gov (United States)

    Asres, Kaleab; Tadesse, Solomon; Mazumder, Avijit; Bucar, Franz

    2012-05-01

    Essential oil from the aerial part of Plectranthus marrubatus J. K. Morton (Lamiaceae), obtained by hydrodistillation was analyzed by gas chromatography/mass spectrometry (GC/MS) and evaluated for antimicrobial and free radical scavenging activities. Twenty-four compounds representing 99% of the total oil were identified. The major constituents were thymol, p-cymene and gamma-terpinene. The oil was tested against 21 bacterial and 4 fungal strains using the disc diffusion method and found to be active against a broad spectrum of pathogens including Gram-positive and Gram-negative bacteria as well as some fungal strains. The minimum inhibitory concentrations (MICs) of the oil against the bacterial strains tested ranged from 10 to 800 microg/mL, and from 400 to 800 microg/mL against the fungal strains employed. The in vitro antioxidant activity was assessed using 2,2-diphenyl-l-picrylhydrazil (DPPH) and showed a low EC50 value of 0.15 microl/mL. The study provides evidence for the broad-spectrum antimicrobial and antioxidant effect of Plectranthus marrubatus essential oil, and a possible explanation for its traditional use in the treatment of cold, fever, stomach disorder, diarrhea and as a skin cleaner.

  20. Free radical scavenging activity, total phenolic and flavonoid contents of mulberry (Morus spp. L., Moraceae extracts

    Directory of Open Access Journals (Sweden)

    Radojković Marija M.

    2012-01-01

    Full Text Available Mulberry (Morus spp. L., Moraceae fruits, leaves, bark and branch have been used in traditional medicine as diuretic, hypoglycemic and hypotensive. The mechanism of their effects is correlated with the content of active components. Objective of this work was to evaluate and compare antioxidant properties of different extracts of two Morus species growing in Serbia: Morus alba L. (white mulberry and Morus nigra L. (black mulberry. Potential antioxidant activity, content of antioxidant compounds (phenolics and flavonoids and radical scavenging capacity, tested by DPPH method, were evaluated. The phenolic and flavonoid composition of different Morus extracts was determined by the HPLC method. The extracts prepared from fruits, leaves and roots of M. alba and M. nigra exhibited different characteristics. The highest extraction yield was achieved by M. alba leaves extraction (23.40%. M. nigra roots extract shown the highest total phenolics (186.30 mg CAE/g, while highest total flavonoids content (67.37 mg RE/g was determined for M. nigra leaves extracts. In addition, black mulberry leaves extracts with the highest antioxidant activity had the highest phenolic acids contents. The dominant phenolic components in the samples were rutin and chlorogenic acid. All investigated mulberry dry extracts shown high content of phenolic compounds and significant antioxidant activity. This work contributes to knowledge of the antioxidant properties of Morus species. The obtained results may be useful in the evaluation of new dietary supplements and food products.

  1. Chemical composition, anti-inflammatory, molluscicidal and free-radical scavenging activities of the leaves of Ficus radicans 'Variegata' (Moraceae).

    Science.gov (United States)

    Naressi, Maria Augusta; Ribeiro, Marcos Alessandro dos Santos; Bersani-Amado, Ciomar Aparecida; Zamuner, Maria Lucilia M; Costa, Willian Ferreira da; Tanaka, Clara M Abe; Sarragiotto, Maria Helena

    2012-01-01

    The methanol crude extract of the leaves of Ficus radicans Roxb. 'Variegata' (Moraceae) and the n-hexane, ethyl acetate and aqueous methanol fractions resulting from its fractionation were evaluated for their anti-inflammatory, molluscicidal and free-radical scavenging activities. The crude extract and fractions exhibited significant inhibition of inflammation in both croton oil (CO)-induced ear oedema in mice (p<0.001) and carrageenan-induced rat paw oedema models (p<0.01). The molluscicidal assay against Biomphalaria glabrata showed a weak activity for the n-hexane fraction (DL(50)= 400 µg mL(-1)). A moderated 1,1-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity was observed for the ethyl acetate fraction (IC(50)= 66.2 µg mL(-1)). Fractionation of the extracts through chromatographic methods afforded the coumarins 7-methoxycoumarin, 7-hydroxy-6-methoxycoumarin and methoxy-3,4-dihydrocoumarin, the steroids β-sitosterol and β-sitosterol 3-O-β-glucopyranoside, as well as a cinnamic acid derivative and a flavonoid identified as trans-4-methoxy-2-β-D-glucopyranosyloxy cinnamic acid and quercetin 3-O-β-D-xylopyranosyl-(1 → 2)-α-L-rhamnopyranoside, respectively. The compounds were identified on the basis of their NMR spectral data and comparison with those previously reported in the literature.

  2. Chemical Composition, In Vitro Antimicrobial, Free-Radical-Scavenging and Antioxidant Activities of the Essential Oil of Leucas inflata Benth

    Directory of Open Access Journals (Sweden)

    Ramzi A. Mothana

    2017-02-01

    Full Text Available The essential oil of Leucas inflata Balf.f. (Lamiaceae, collected in Yemen, was analyzed using gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS techniques. Forty-three components were recognized, representing 89.2% of the total oil. The L. inflata volatile oil was found to contain a high percentage of aliphatic acids (51.1%. Hexadecanoic acid (32.8% and n-dodecanoic acid (7.8% were identified as the major compounds. Oxygenated monoterpenes were distinguished as the second significant group of constituents (16.0%. Camphor (6.1% and linalool (3.2% were found to be the main components among the oxygenated monoterpenes. In addition, the volatile oil was assessed for its antimicrobial activity against four bacterial strains and one yeast species using broth micro-dilution assay for minimum inhibitory concentrations (MIC. In addition, antioxidant activity was measured utilizing the anti-radical activity of the sable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH and β-Carotene-linoleic acid assays. The oil of L. inflata showed an excellent antibacterial activity against only the tested Gram-positive bacteria with a MIC-value of 0.81 mg/mL. Furthermore, the oil demonstrated, at a concentration of 1 mg/mL, a weak to moderate antiradical and antioxidant activity of 38% and 32%, respectively.

  3. Enhanced photostability, radical scavenging and antitumor activity of indole-3-carbinol-loaded rose hip oil nanocapsules.

    Science.gov (United States)

    Gehrcke, Mailine; Giuliani, Laura Minussi; Ferreira, Luana Mota; Barbieri, Allanna Valentini; Sari, Marcel Henrique Marcondes; da Silveira, Elita Ferreira; Azambuja, Juliana Hofstatter; Nogueira, Cristina Wayne; Braganhol, Elizandra; Cruz, Letícia

    2017-05-01

    This study aimed to develop poly(ε-caprolactone) nanocapsules loaded with indole-3-cabinol (I3C) using rose hip oil (RHO) or medium chain triglycerides (MCT) as oil core. In vitro radical scavenging activity (DPPH method), hemolysis, and antitumor effects on breast (MCF-7) and glioma (C6) cells were conducted. Preformulation evaluations revealed that RHO is suitable to prepare the nanocapsules considering the log P determination and dissolution/swelling experiments of polymer films. The nanocapsules were prepared and presented adequate physicochemical characteristics as mean size around 250nm, polydispersity index values oil core (RHO or MCT) on these parameters. However, the photodegradation study demonstrated that RHO nanocapsules showed less degree of I3C degradation in comparison to MCT nanocapsules. The in vitro release profile showed that both nanocapsule suspensions demonstrated an initial burst effect followed by a prolonged I3C release. In addition, the formulations were considered hemocompatibles at 10μg/mL and showed an enhanced radical scavenging activity in comparison to free I3C. Moreover, nanocapsules prepared with RHO increased about two times the antitumor effect of I3C on MCF-7 and C6 cells without significant reduction of astrocyte cell viability. In conclusion, nanocapsule formulations developed in this study might be considered promising for cancer treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. How to counter radical narratives: Dutch deradicalization policy in the case of Moluccan and Islamic radicals

    NARCIS (Netherlands)

    Demant, F.; de Graaf, B.

    2010-01-01

    This article deals with the role of government in encouraging the decline of radical movements. The question posed is: "Which story can the government tell to encourage the decline of radical groups and the disengagement of their members?" The article makes use of the survey of factors promoting

  5. Modeling Radicalization Phenomena in Heterogeneous Populations.

    Directory of Open Access Journals (Sweden)

    Serge Galam

    Full Text Available The phenomenon of radicalization is investigated within a mixed population composed of core and sensitive subpopulations. The latest includes first to third generation immigrants. Respective ways of life may be partially incompatible. In case of a conflict core agents behave as inflexible about the issue. In contrast, sensitive agents can decide either to live peacefully adjusting their way of life to the core one, or to oppose it with eventually joining violent activities. The interplay dynamics between peaceful and opponent sensitive agents is driven by pairwise interactions. These interactions occur both within the sensitive population and by mixing with core agents. The update process is monitored using a Lotka-Volterra-like Ordinary Differential Equation. Given an initial tiny minority of opponents that coexist with both inflexible and peaceful agents, we investigate implications on the emergence of radicalization. Opponents try to turn peaceful agents to opponents driving radicalization. However, inflexible core agents may step in to bring back opponents to a peaceful choice thus weakening the phenomenon. The required minimum individual core involvement to actually curb radicalization is calculated. It is found to be a function of both the majority or minority status of the sensitive subpopulation with respect to the core subpopulation and the degree of activeness of opponents. The results highlight the instrumental role core agents can have to hinder radicalization within the sensitive subpopulation. Some hints are outlined to favor novel public policies towards social integration.

  6. [Lower urinary tract dysfunction following radical hysterectomy].

    Science.gov (United States)

    Aoun, F; Roumeguère, T

    2015-12-01

    Radical hysterectomy is associated with a significant amount of urinary functional complications and a negative impact on quality of life. The aim of this review is to provide a comprehensive overview of the neurological etiology of lower urinary tract dysfunction following radical hysterectomy and to establish an optimal postoperative management strategy. We performed a comprehensive overview using the following terms: "radical hysterectomy" and "urologic diseases etiology" or "urologic disease prevention and control". The reported incidence of lower urinary tract dysfunction after radical hysterectomy varies from 12 to 85%. Several animal and clinical urodynamic studies corroborate the neurologic etiology of the dysfunction. Lower urinary tract dysfunction is a common postoperative finding (70-85%) but spontaneous recovery is to be expected within 6-12 months after surgery. The most frequent long term sequela is stress urinary incontinence (40% of cases) and its management is complex and challenging. Postoperative refractory overactive bladder and bladder underactivity can be treated by neuromodulation of sacral roots and superior hypogastric plexus, respectively. In the absence of good clinical predictors, preoperative urodynamic examinations could have a role in understanding the pathophysiology of the dysfunction before such interventions. The pathophysiology of lower urinary tract dysfunction following radical hysterectomy is multifactorial. Its management is complex and should be multidisciplinary. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  7. Introducing Stable Radicals into Molecular Machines.

    Science.gov (United States)

    Wang, Yuping; Frasconi, Marco; Stoddart, J Fraser

    2017-09-27

    Ever since their discovery, stable organic radicals have received considerable attention from chemists because of their unique optical, electronic, and magnetic properties. Currently, one of the most appealing challenges for the chemical community is to develop sophisticated artificial molecular machines that can do work by consuming external energy, after the manner of motor proteins. In this context, radical-pairing interactions are important in addressing the challenge: they not only provide supramolecular assistance in the synthesis of molecular machines but also open the door to developing multifunctional systems relying on the various properties of the radical species. In this Outlook, by taking the radical cationic state of 1,1'-dialkyl-4,4'-bipyridinium (BIPY •+ ) as an example, we highlight our research on the art and science of introducing radical-pairing interactions into functional systems, from prototypical molecular switches to complex molecular machines, followed by a discussion of the (i) limitations of the current systems and (ii) future research directions for designing BIPY •+ -based molecular machines with useful functions.

  8. Analysis of radicals induced in irradiated foods

    International Nuclear Information System (INIS)

    Kishida, Keigo; Kaimori, Yoshihiko; Kawamura, Shoei; Sakamoto, Yuhki; Nakamura, Hideo; Ukai, Mitsuko; Kikuchi, Masahiro; Shimoyama, Yuhei; Kobayashi, Yasuhiko

    2012-01-01

    By electron spin resonance (ESR) spectroscopy, we revealed free radicals in γ-ray irradiated foods; black pepper, green coffee bean and ginseng. We also analyzed the decay behavior of radiation induced free radicals during storage of irradiated foods. The ESR spectrum of experimental irradiated foods consists of a sextet signal centered at g=2.0 and a singlet signal at the same g-value position and a singlet signal at g=4.0. The singlet signal at g=2.0 is originated from organic free radicals and its peak intensity showed the dependence of γ-ray irradiation dose levels. The signal intensity was decreased during storage. Only after 3 hours of radiation treatment the peak intensity was decreased fast and after that the intensity was decreased slowly. The relaxation times, T 1 and T 2 , of radiation induced free radicals showed the variations before and after irradiation. During long time storage period it was shown that T 1 was increased and T 2 was decreased. By analysis of decay process using the simulation methods based on the theory of reaction speed, it is considered that at least two kinds of radicals were induced in irradiated foods during long time storage. (author)

  9. Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand

    Directory of Open Access Journals (Sweden)

    Chantarudee Atip

    2012-04-01

    Full Text Available Abstract Background Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp. and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Methods Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L. pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50. The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. Results The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold higher in the bee corn pollen (EC50 = 7.42 ± 0.12 μg/ml, than the floral corn pollen (EC50 = 212 ± 13.6% μg/ml. After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including

  10. Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand

    Science.gov (United States)

    2012-01-01

    Background Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp.) and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Methods Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L.) pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM) and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50). The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. Results The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold) higher in the bee corn pollen (EC50 = 7.42 ± 0.12 μg/ml), than the floral corn pollen (EC50 = 212 ± 13.6% μg/ml). After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including biotin (56.7 μg/100

  11. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  12. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  13. Breaking the dogma: PCB-derived semiquinone free radicals do not form covalent adducts with DNA, GSH, and amino acids.

    Science.gov (United States)

    Wangpradit, Orarat; Rahaman, Asif; Mariappan, S V Santhana; Buettner, Garry R; Robertson, Larry W; Luthe, Gregor

    2016-02-01

    Covalent bond formations of free radical metabolites with biomolecules like DNA and proteins are thought to constitute a major mechanism of toxicity and carcinogenesis. Glutathione (GSH) is generally accepted as a radical scavenger protecting the cell. In the present study, we investigated a semiquinone radical (SQ(●-)) metabolite of the semivolatile 4-chlorobiphenyl, using electron paramagnetic resonance spectroscopy, and oxygen consumption. Proton nuclear magnetic resonance ((1)H NMR) and liquid chromatography-mass spectrometry (LC-MS) were also employed to elucidate the radical interaction with DNA, amino acids, and GSH. We found that DNA and oligonucleotides stabilized SQ(●-) by electron delocalization in the π-stacking system, resulting in persistent radical intercalated, rather than forming a covalent bond with SQ(●-). This finding was strongly supported by the semiempirical calculation of the semioccupied molecular orbital and the linear combination of the atomic orbitals, indicating 9.8 kcal mol(-1) energy gain. The insertion of SQ(●-) into the DNA strand may result in DNA strand breaks and interruption of DNA replication process or even activate radical mediated secondary reactions. The presence of amino acids resulted in a decrease of the electron paramagnetic resonance (EPR) signal of SQ(●-) and correlated with their isoelectric points. The pH shifts the equilibrium of the dianions of hydroquinone and influenced indirectly the formation of SQ(●-). Similar findings were observed with GSH and Cys. GSH and Cys functioned as indirect radical scavengers; their activities depend on their chemical equilibria with the corresponding quinones, and their further reaction via Michael addition. The generally accepted role of GSH as radical scavenger in biological systems should be reconsidered based upon these findings, questioning the generally accepted view of radical interaction of semiquinones with biologically active compounds, like DNA, amino acids

  14. Resveratrol products resulting by free radical attack

    Science.gov (United States)

    Bader, Yvonne; Quint, R. M.; Getoff, Nikola

    2008-06-01

    Trans-resveratrol ( trans-3,4',5-trihydroxystilbene; RES), which is contained in red wine and many plants, is one of the most relevant and extensively investigated stilbenes with a broad spectrum of biological activities. Among other duties, RES has been reported to have anti-carcinogenetic activities, which could be attributed to its antioxidant properties. The degradation of RES was studied under various conditions. The products (aldehydes, carboxylic acids, etc.) generated from RES by the attack of free radicals were registered as a function of the radical concentration (absorbed radiation dose). Based on the obtained data it appears that the OH radicals are initiating the rather complicated process, which involves of the numerous consecutive reactions. A possible starting reaction mechanism is presented.

  15. Exploring How Lead Users Develop Radical Innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher; Hienerth, Christoph; Gemuenden, Hans Georg

    2008-01-01

    In this study, we explore how lead users develop radical innovations outside of manufacturing firms. We analyze the transition from a very early stage of activities to the ultimate commercialization of these innovations. The focus in this context is on the initiatives undertaken by lead users...... lead users as surgeons launch entrepreneurial activities and bridge periods in which established medical equipment manufacturers would not risk investing in radical innovations. By doing so, lead users create the conditions usually provided in manufacturer-initiated lead user projects, including...... the supply of diversified knowledge, the development and coordination of a network for further development of the innovation, and initial tests of technical or market feasibility. Our findings have implications for manufacturing firms that wish to design radical innovation projects with (individual) lead...

  16. Customers as Partners in Radical Service Innovation

    DEFF Research Database (Denmark)

    Scupola, Ada; Nicolajsen, Hanne Westh

    2009-01-01

      Purpose- The main purpose of this paper is to investigate customer involvement and related challenges in radical service innovations in engineering consulting services Design/methodology/approach - The paper uses a case study approach and so called rich descriptions to investigate customer...... involvement, roles and related challenges and conditions in radical service innovations.Findings- One main finding is that customers can engage in radical service innovations in engineering consultancy services and may play a decisive role. In doing this they most likely take on all the three user involvement...... roles defined in the literature of New Service and New Product Development. Also a number of conditions are found to be necessary in order for this collaboration to succeed. The conclusion is that another understanding and handling of the customer/supplier relation is needed along with a need...

  17. Optimal pain management for radical prostatectomy surgery

    DEFF Research Database (Denmark)

    Joshi, Grish P; Jaschinski, Thomas; Bonnet, Francis

    2015-01-01

    BACKGROUND: Increase in the diagnosis of prostate cancer has increased the incidence of radical prostatectomy. However, the literature assessing pain therapy for this procedure has not been systematically evaluated. Thus, optimal pain therapy for patients undergoing radical prostatectomy remains...... controversial. METHODS: Medline, Embase, and Cochrane Central Register of Controlled Trials were searched for studies assessing the effects of analgesic and anesthetic interventions on pain after radical prostatectomy. All searches were conducted in October 2012 and updated in June 2015. RESULTS: Most...... treatments studied improved pain relief and/or reduced opioid requirements. However, there were significant differences in the study designs and the variables evaluated, precluding quantitative analysis and consensus recommendations. CONCLUSIONS: This systematic review reveals that there is a lack...

  18. A Radically Configurable Six-State Compound

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J.C.; Fahrenbach, Albert C.; Cao, Dennis; Dyar, Scott M.; Frasconi, M.; Giesener, M. A.; Benítez, D.; Tkatchouk, E.; Li, H.; Stern, Charlotte L.; Sarjeant, Amy A.; Hartlieb, K.J.; Liu, Z.; Carmieli, Raanan; Botros, Y.Y.; Wasielewski, M. R.; Goddard III, W.A.; Stoddart, J. Fraser

    2013-01-24

    Most organic radicals possess short lifetimes and quickly undergo dimerization or oxidation. Here, we report on the synthesis by radical templation of a class of air- and water-stable organic radicals, trapped within a homo[2]catenane composed of two rigid and fixed cyclobis(paraquat-p-phenylene) rings. The highly energetic octacationic homo[2]catenane, which is capable of accepting up to eight electrons, can be configured reversibly, both chemically and electrochemically, between each one of six experimentally accessible redox states (0, 2+, 4+, 6+, 7+, and 8+) from within the total of nine states evaluated by quantum mechanical methods. All six of the observable redox states have been identified by electrochemical techniques, three (4+, 6+, and 7+) have been characterized by x-ray crystallography, four (4+, 6+, 7+, and 8+) by electron paramagnetic resonance spectroscopy, one (7+) by superconducting quantum interference device magnetometry, and one (8+) by nuclear magnetic resonance spectroscopy.

  19. Inhibition and Promotion of Pyrolysis by Hydrogen Sulfide (H2S) and Sulfanyl Radical (SH)

    DEFF Research Database (Denmark)

    Zeng, Zhe; Altarawneh, Mohammednoor; Oluwoye, Ibukun

    2016-01-01

    the weakest C–H sites in alkenes and alkynes, except for ethylene, appears noticeably exothermic. Furthermore, abstraction of H from propene, 1-butene, and iso-butene displays pronounced spontaneity (i.e., ΔrG° hydrogen bond. However......, an alkyl radical readily abstracts H atom from H2S, with H2S acting as a potent scavenger for alkyl radicals in combustion processes. That is, these reactions proceed in the opposite direction than those involving SH and alkene or alkyne species, exhibiting shallow barriers and strong spontaneity. Our...... findings demonstrate that the documented inhibition effect of hydrogen sulfide (H2S) on pyrolysis of alkanes does not apply to alkenes and alkynes. During interaction with hydrocarbons, the inhibitive effect of H2S and promoting interaction of SH radical depend on the reversibility of the H abstraction...

  20. Generation of OH Radical by Ultrasonic Irradiation in Batch and Circulatory Reactor

    Science.gov (United States)

    Fang, Yu; Shimizu, Sayaka; Yamamoto, Takuya; Komarov, Sergey

    2018-03-01

    Ultrasonic technology has been widely investigated in the past as one of the advance oxidation processes to treat wastewater, in this process acoustic cavitation causes generation of OH radical, which play a vital role in improving the treatment efficiency. In this study, OH radical formation rate was measured in batch and circulatory reactor by using Weissler reaction at various ultrasound output power. It is found that the generation rate in batch reactor is higher than that in circulatory reactor at the same output power. The generation rate tended to be slower when output power exceeds 137W. The optimum condition for circulatory reactor was found to be 137W output and 4L/min flow rate. Results of aluminum foil erosion test revealed a strong dependence of cavitation zone length on the ultrasound output power. This is assumed to be one of the reasons why the generation rate of HO radicals becomes slower at higher output power in circulatory reactor.

  1. Rydberg states of the SH(SD) radical revealed by multiphoton ionization spectroscopy

    Science.gov (United States)

    Ashfold, M. N. R.; Tutcher, B.; Western, C. M.

    Three hitherto uncharacterized Rydberg states of the SD radical, each arising from a … 5σ22π24p1 ← … 5σ22π3 electronic promotion, have been identified through analysis of the rotationally structured two photon resonance enhancements each provides to the multiphoton ionization spectrum of this species. One, possessing 2Σ- symmetry, had actually been observed (but not recognized as such) in an earlier absorption study. The others, of 2Π and 2Φ symmetry, have not been reported previously. The SH radical was also observed to exhibit fragmentary rotational structure in the wavelength regions of the 2Σ--X2Π and 2Φ-X2Π transitions. The results provide strong support for the ab initio theoretical analysis of the vertical electronic spectrum of the mercapto radical by Bruna and Hirsch (1987, Molec. Phys., 61, 1359).

  2. Comparative EPR studies of free radicals in melanin synthesized by Bacillus weihenstephanensis soil strains

    Science.gov (United States)

    Zdybel, Magdalena; Pilawa, Barbara; Drewnowska, Justyna M.; Swiecicka, Izabela

    2017-07-01

    EPR spectroscopy was used to examine the properties of and free radical concentrations in atypical water-soluble melanin-like pigments from Bacillus weihenstephanensis strains. The same EPR spectral shape was observed in bacterial melanins as in eumelanin. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR lines indicated slow spin-lattice relaxation processes in the samples. Strong dipolar interactions characterized the tested melanin samples. Higher free radical concentrations were found in bacterial melanin than in synthetic melanin. The free radical concentrations in melanin from B. weihenstephanensis increased in the following order: strain JAS 81/4 < JAS 83/3 < JAS 86/1 < JAS 39/1.

  3. Free radical scavenging capacity and antioxidant activity of methanolic and ethanolic extracts of plum (Prunus domestica L. in both fresh and dried samples

    Directory of Open Access Journals (Sweden)

    Amin Morabbi Najafabad

    2014-09-01

    Full Text Available Objectives: Consumption of fruits, such as plums and prunes, is useful in treating blood circulation disorder, measles, digestive disorder, and prevention of cancer, diabetes, and obesity. The paper presents a description of antioxidant and antiradical capacity of plum (Prunus domestica L. in both fresh and dried samples. Materials and Methods: Samples were mixed with methanol and ethanol (as solvents and were extracted on magnetic shaker, separately. The experiments were carried out to measure the Total Phenolic Content (TPC, Total Flavonoid Content (TFC, Total Antioxidant Capacity (TAC, Reducing Power Assay (RPA, Chain Breaking Activity (CBA, and quantity of Malondialdehyde (MDA, 2,2-Diphenyl-1-Picrylhydrazyl (DPPH,Nitric Oxide (NO,Hydrogen peroxide (H2O2 and superoxide(O2- radicals inhibition. Results: The results showed that the highest values for the TPC, TFC,TAC, RPA, CBA, DPPH, and NO were related to ethanolic extractsof dried sample which showed statistically significant differences (p2O2 and O2-were related to ethanolic extracts of fresh sample. The correlations data were analyzed among all parameters and the TPC and TFC had a significant correlation (r2=0.977. Moreover, it was found that methanol was more successful in extraction procedure than ethanol (p

  4. Ethanol extract of Tetrapleura tetraptera fruit peels: Chemical characterization, and antioxidant potentials against free radicals and lipid peroxidation in hepatic tissues

    Directory of Open Access Journals (Sweden)

    Ochuko L. Erukainure

    2017-11-01

    Full Text Available The chemical and antioxidant properties of the ethanolic extract of Tetrapleura tetraptera fruit peels were investigated. Dried peels of T. tetraptera fruits were extracted with ethanol. The extract was subjected to preliminary phytochemical screening using standard procedures. GC–MS was used in identifying the secondary metabolites. The antioxidant properties of the extract were determined by its ferric reducing activity, 2,2′-diphenyl-1-picrylhydrazyl (DPPH and nitric oxide (NO radicals scavenging activities, and the inhibition of lipid peroxidation in hepatic tissues of albino male rats. Preliminary phytochemical screening revealed the presence of flavonoids, phenols, tannins, saponins, terpenoids and phlebotannin. GC–MS analysis revealed the presence of D-fructose, piperazine, octodrine, glycidol, glyceraldehydes, 6-octadecenoic acid and 9,12-octadecenoic acid, with D–fructose being the most predominant compound. The extract exhibited high antioxidant activities both in vitro and ex vivo, as indicated by its ability to scavenge DPPH and nitric oxide as well as inhibition of lipid peroxidation. This is further portrayed by its ferric reducing activity. These results suggest an antioxidant protective effect of the extract against oxidative hepatic damage and can be attributed to a synergetic action of the identified bioactive compounds. Keywords: Antioxidant, Lipid peroxidation, Phytochemicals, Secondary metabolites

  5. Progress in Resonance Enhanced Multiphoton Ionization Spectroscopy of Transient Free Radicals

    Science.gov (United States)

    Hudgens, Jeffrey W.

    The following sections are included: * IntroductioN * An Overview of Rehpi Spectroscopy * A Brief History * The Rempi Mechanism * Multiphoton Selection Rules * Characteristics of Rydberg States * Experimental Elements * Apparatus * Identification of Spectral Carriers * The Unique Role of Mass Spectrometry * REMPI Mass Spectra of Free Radicals Show Little Fragmentation * Determination of the Photon Order of the Resonant State * Summary of Transient Radicals Studied By Rempi Spectroscopy * Diatomic Radicals * CF Radical * CH Radical * REMPI Spectra of ClO and BrO Radicals * ClO * BrO * CCl Radical * NH (a1 Δ) Radical * PH (b 1Σ+) Radical * PO Radical * SiF Radical * Triatomic Radicals * CCO Radical * NH2 Radical * HCO Radical * SiF2 Radical * Methyl Radical * One Photon Resonance Enhanced Ionization * Three Photon REMPI of Methyl radicals * Two Photon Spectroscopy * The np ^{2}A^{primeprime}_{2}l←l← tildeX ^{2}A^{primeprime}_{2} Bands * The nf ^{2}E^{prime} l← l← tildeX ^{2}A^{primeprime}_{2} Bands * Substituted Methyl Radicals * CH2F Radical * CHCl2 Radical * CH2OH Radical * CF3 Radical * Other Polyatomic Radicals * Allyl and 2-Methvlallyl Radicals * Substituted Allyl Radicals * Benzyl Radical * Cyclohexanyl radicals * Ethyl Radical * Methoxy Radical * Acknowledgments * References

  6. Mechanisms of radical removal by SO2

    DEFF Research Database (Denmark)

    Rasmussen, Christian Lund; Glarborg, Peter; Marshall, Paul

    2007-01-01

    It is well established from experiments in premixed, laminar flames, jet-stirred reactors, flow reactors, and batch reactors that SO2 acts to catalyze hydrogen atom removal at stoichiometric and reducing conditions. However, the commonly accepted mechanism for radical removal, SO2 + H(+M) reversi......It is well established from experiments in premixed, laminar flames, jet-stirred reactors, flow reactors, and batch reactors that SO2 acts to catalyze hydrogen atom removal at stoichiometric and reducing conditions. However, the commonly accepted mechanism for radical removal, SO2 + H...

  7. Resonance ionization detection of combustion radicals

    Energy Technology Data Exchange (ETDEWEB)

    Cool, T.A. [Cornell Univ., Ithaca, NY (United States)

    1993-12-01

    Fundamental research on the combustion of halogenated organic compounds with emphasis on reaction pathways leading to the formation of chlorinated aromatic compounds and the development of continuous emission monitoring methods will assist in DOE efforts in the management and disposal of hazardous chemical wastes. Selective laser ionization techniques are used in this laboratory for the measurement of concentration profiles of radical intermediates in the combustion of chlorinated hydrocarbon flames. A new ultrasensitive detection technique, made possible with the advent of tunable VUV laser sources, enables the selective near-threshold photoionization of all radical intermediates in premixed hydrocarbon and chlorinated hydrocarbon flames.

  8. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  9. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  10. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  11. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  12. Competing with the radical right. Distances between the European radical right and other parties on typical radical right issues

    NARCIS (Netherlands)

    Immerzeel, T.|info:eu-repo/dai/nl/357424875; Lubbers, M.|info:eu-repo/dai/nl/229636756; Coffe, H.R.|info:eu-repo/dai/nl/304824186

    2015-01-01

    The popularity of European Radical Right Populist parties (RRPs) has led to investigations into the distances between RRPs’ and other parties’ stances regarding immigration. This article adds to this literature by investigating the distance between RRPs and the other parties on a wider variety of

  13. Competing with the radical right: Distances between the European radical right and other parties on typical radical right issues

    NARCIS (Netherlands)

    Immerzeel, T.; Lubbers, M.; Coffé, H.

    2016-01-01

    The popularity of European Radical Right Populist parties (RRPs) has led to investigations into the distances between RRPs' and other parties' stances regarding immigration. This article adds to this literature by investigating the distance between RRPs and the other parties on a wider variety of

  14. Free radical behaviours during methylene blue degradation in the Fe2+/H2O2 system.

    Science.gov (United States)

    Wang, Zhonghua; Zhao, Haiqian; Qi, Hanbing; Liu, Xiaoyan; Liu, Yang

    2017-12-22

    Behaviours of the free radicals during the methylene blue (MB) oxidation process in the Fe 2+ /H 2 O 2 system were studied to reveal the reason for the low utilization efficiency of H 2 O 2 . The roles of [Formula: see text], [Formula: see text] and [Formula: see text] radicals were proven to be different in the MB oxidation process. The results showed that [Formula: see text] radicals had a strong ability to oxidize MB; however, they were not the main active substances for MB degradation due to the low concentration in the traditional Fe 2+ /H 2 O 2 system. [Formula: see text] radicals could not oxidize MB. [Formula: see text] radicals were the main active substances for MB oxidation. In the short initial stage, the utilization efficiency of H 2 O 2 was high, because the generation rate of [Formula: see text] was much higher than that of [Formula: see text]. More [Formula: see text] radicals were involved in the MB oxidation reaction. In the long deceleration stage (after the short initial stage), a large amount of H 2 O 2 was consumed, but the amount of oxidized MB was very small. Most of the [Formula: see text] radicals were consumed via the rapid useless reaction between [Formula: see text] and [Formula: see text] in this stage, resulting in the serious useless consumption of H 2 O 2 . It is a feasible method to improve the utilization efficiency of H 2 O 2 by adding suitable additives into the Fe 2+ /H 2 O 2 system to weaken the useless reaction between [Formula: see text] and [Formula: see text].

  15. Homogenate-assisted Vacuum-powered Bubble Extraction of Moso Bamboo Flavonoids for On-line Scavenging Free Radical Capacity Analysis.

    Science.gov (United States)

    Sun, Yinnan; Yang, Kui; Cao, Qin; Sun, Jinde; Xia, Yu; Wang, Yinhang; Li, Wei; Ma, Chunhui; Liu, Shouxin

    2017-07-11

    A homogenate-assisted vacuum-powered bubble extraction (HVBE) method using ethanol was applied for extraction of flavonoids from Phyllostachys pubescens (P. pubescens) leaves. The mechanisms of homogenate-assisted extraction and vacuum-powered bubble generation were discussed in detail. Furthermore, a method for the rapid determination of flavonoids by HPLC was established. HVBE followed by HPLC was successfully applied for the extraction and quantification of four flavonoids in P. pubescens , including orientin, isoorientin, vitexin, and isovitexin. This method provides a fast and effective means for the preparation and determination of plant active components. Moreover, the on-line antioxidant capacity, including scavenging positive ion and negative ion free radical capacity of different fractions from the bamboo flavonoid extract was evaluated. Results showed that the scavenging DPPH ˙ free radical capacity of vitexin and isovitexin was larger than that of isoorientin and orientin. On the contrary, the scavenging ABTS⁺ ˙ free radical capacity of isoorientin and orientin was larger than that of vitexin and isovitexin.

  16. Comparative analysis of radical scavenging and antioxidant activity of phenolic compounds present in everyday use spice plants by means of spectrophotometric and chromatographic methods.

    Science.gov (United States)

    Stankevičius, Mantas; Akuņeca, Ieva; Jãkobsone, Ida; Maruška, Audrius

    2011-06-01

    Comparative analysis of radical scavenging and antioxidant activities of phenolic compounds present in everyday use spice plants was carried out by means of spectrophotometric and chromatographic methods. Six spice plant samples, namely onion (Allium cepa), parsley (Petroselinum crispum) roots and leaves, celery (Apium graveolens) roots and leaves and leaves of dill (Anethum graveolens) were analyzed. Total amount of phenolic compounds and radical scavenging activity (RSA) was the highest in celery leaves and dill extracts and was the lowest in celery roots. Comparing commonly used spectrophotometric analysis of 2,2-diphenyl-1-picrylhydrazyl (DPPH) RSA of extracts with the results obtained using reversed-phase chromatographic separation with on-line post-column radical scavenging reaction detection, good correlation was obtained (R(2)=0.848). Studies using HPLC system with electrochemical detector showed that bioactive phytochemicals can be separated and antioxidant activities of individual compounds evaluated without the need of a complex HPLC system with reaction detector. The results obtained using electrochemical detection correlate with the RSA assayed using spectrophotometric method (R(2)=0.893). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Free radical scavenging action of Bio-catalyzer alpha.rho No.11 (Bio-normalyzer) and its by-product.

    Science.gov (United States)

    Santiago, L A; Osato, J A; Hiramatsu, M; Edamatsu, R; Mori, A

    1991-01-01

    Bio-catalyzer alpha.rho No.11 (Bio-normalyzer) and its by-product are natural health products made by yeast fermentation of glucose, Carica papaya Linn., Pennisetum pupureum Schum., and Sechium edule Swartz. Their effects on free radicals were examined by electron spin resonance spectrometry using spin trapping agent 5,5-dimethyl-1-pyrroline-1-oxide (DMPO). It was observed that both Bio-catalyzer and its by-product scavenged 95% of DMPO-OH spin adducts (89 x 10(15) spins/ml) generated by FeSO4-H2O2-diethylene triamine pentaacetic acid system at 45.45 mg/ml each. Five percent of DMPO-O2- spin adducts (27 x 10(15) spins/ml) generated by hypoxanthine-xanthine oxidase system and 11% of 1,1-diphenyl-2-picrylhydrazyl radicals (7 x 10(15) spins/ml) were quenched using 25 mg/ml of Bio-catalyzer while 5% of superoxide and nil DPPH radicals were scavenged by its by-product. Vivo tests showed that oral administration of 1-g/kg body weight of Bio-catalyzer significantly inhibited thiobarbituric acid reactive substances formation, which is an index of lipid peroxidation, in the FeCl3-induced epileptic focus of rats. These findings suggest that Bio-catalyzer or its by-product may be useful health foods against neural lipid peroxidation, traumatic epilepsy and aging.

  18. Laboratory studies of nitrate radical chemistry - application to atmospheric processes

    Energy Technology Data Exchange (ETDEWEB)

    Noremsaune, Ingse

    1997-12-31

    This thesis studies atmospheric chemistry and tries in particular to fill gaps in the data base of atmospheric reactions. It studies the nitrate radical reactions with chloroethenes and with but-2-yne (2-butyne). The mechanisms and rate coefficients for the NO{sub 3}-initiated degradation of the chloroethenes and 2-butyne were investigated by means of the static reaction chamber and the fast flow-discharge technique. The reactions between the nitrate radical and the chloroethenes were studied at atmospheric pressure in a reaction chamber with synthetic air as bath gas. FTIR (Fourier Transform InfraRed spectroscopy) spectroscopy was used to follow the reactions and to identify the products. Products were observed for the reactions with (E)-1,2-dichloroethene and tetrachloroethene, although the absorption bands are weak. The alkyl peroxynitrate and nitrate compounds form very strong and characteristic absorption bands. The rate coefficients for the reactions between NO{sub 3} and the chloroethenes were investigated at room temperature by three different methods. The results are given in tables. 132 refs., 44 figs., 21 tabs.

  19. A trinuclear radical-bridged lanthanide single-molecule magnet

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Colin A.; Darago, Lucy E.; Gonzalez, Miguel I. [Department of Chemistry, University of California, Berkeley, CA (United States); Demir, Selvan [Institut fuer Anorganische Chemie, Georg-August-Universitaet, Goettingen (Germany); Long, Jeffrey R. [Department of Chemistry, University of California, Berkeley, CA (United States); Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2017-08-14

    Assembly of the triangular, organic radical-bridged complexes Cp*{sub 6}Ln{sub 3}(μ{sub 3}-HAN) (Cp*=pentamethylcyclopentadienyl; Ln=Gd, Tb, Dy; HAN=hexaazatrinaphthylene) proceeds through the reaction of Cp*{sub 2}Ln(BPh{sub 4}) with HAN under strongly reducing conditions. Significantly, magnetic susceptibility measurements of these complexes support effective magnetic coupling of all three Ln{sup III} centers through the HAN{sup 3-.} radical ligand. Thorough investigation of the Dy{sup III} congener through both ac susceptibility and dc magnetic relaxation measurements reveals slow relaxation of the magnetization, with an effective thermal relaxation barrier of U{sub eff}=51 cm{sup -1}. Magnetic coupling in the Dy{sup III} complex enables a large remnant magnetization at temperatures up to 3.0 K in the magnetic hysteresis measurements and hysteresis loops that are open at zero-field up to 3.5 K. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Free radical scavenging and anti-acne activities of mangosteen fruit rind extracts prepared by different extraction methods.

    Science.gov (United States)

    Pothitirat, Werayut; Chomnawang, Mullika Traidej; Supabphol, Roongtawan; Gritsanapan, Wandee

    2010-02-01

    The ethanol extracts of mangosteen fruit rinds prepared by several extraction methods were examined for their contents of bioactive compounds, DPPH-scavenging activity, and anti-acne producing bacteria against Propionibacterium acnes and Staphylococcus epidermidis. The dried powder of the fruit rind was extracted with 95% ethanol by maceration, percolation, Soxhlet extraction, ultrasonic extraction, and extraction using a magnetic stirrer. Soxhlet extraction promoted the maximum contents of crude extract (26.60% dry weight) and alpha-mangostin (13.51%, w/w of crude extract), and also gave the highest anti-acne activity with MIC 7.81 and 15.63 microg/mL and MBC 15.53 and 31.25 microg/mL against P. acnes and S. epidermidis, respectively. Ethanol 70% and 50% (v/v) were also compared in Soxhlet extraction. Ethanol 50% promoted the extract with maximum amounts of total phenolic compounds (26.96 g gallic acid equivalents/100 g extract) and total tannins (46.83 g tannic acid equivalents/100 g extract), and also exhibited the most effective DPPH-scavenging activity (EC(50) 12.84 microg/mL). Considering various factors involved in the process, Soxhlet extraction carried a low cost in terms of reagents and extraction time. It appears to be the recommended extraction method for mangosteen fruit rind. Ethanol 50% should be the appropriate solvent for extracting free radical-scavenging components, phenolic compounds, and tannins, while 95% ethanol is recommended for extraction of alpha-mangostin, a major anti-acne component from this plant.

  1. Peroxy Radical Chemistry and Partitioning under a Ponderosa Pine Canopy

    Science.gov (United States)

    Wolfe, G. M.; Cantrell, C. A.; Mauldin, L.; Kim, S.; Henry, S. B.; Boyle, E. S.; Karl, T.; Harley, P. C.; Turnipseed, A.; Zheng, W.; Flocke, F. M.; Apel, E. C.; Hornbrook, R. S.; Hall, S. R.; Ullmann, K.; Guenther, A. B.; DiGangi, J. P.; Kaser, L.; Schnitzhofer, R.; Hansel, A.; Graus, M.; Nakashima, Y.; Kajii, Y. J.; Keutsch, F. N.

    2012-12-01

    As the first intermediates in the OH-initiated oxidation of hydrocarbons, peroxy radicals are central to the photochemistry of the lower atmosphere. Peroxy radical abundance and partitioning controls relative rates of radical propagation and termination in low-NOx regimes, and the coupled cycling of these molecules lies at the heart of recently-highlighted deficiencies in traditional chemical mechanisms. Using observations of hydroperoxy (HO2) and total peroxy (HO2 + RO2) radicals acquired during the summer 2010 BEACHON-ROCs campaign, we explore the processes affecting radical-mediated chemistry within a rural Ponderosa pine forest in central Colorado. Steady-state and fully-coupled 0-D modeling studies are used to provide complementary perspectives on our understanding of the radical budget in this environment. Analysis will focus on the nature and impact of unidentified radical sources and sinks and on how the composition of the peroxy radical pool modulates radical regeneration.

  2. Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

    Directory of Open Access Journals (Sweden)

    Béla Fiser

    Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

  3. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  4. Antioxidative effects of Kimchi under different fermentation stage on radical-induced oxidative stress.

    Science.gov (United States)

    Kim, Boh Kyung; Choi, Ji Myung; Kang, Soon Ah; Park, Kun Young; Cho, Eun Ju

    2014-12-01

    Kimchi is a traditional Korean fermented vegetable containing several ingredients. We investigated the protective activity of methanol extract of kimchi under different fermentation stages against oxidative damage. Fresh kimchi (Fresh), optimally ripened kimchi (OptR), and over ripened kimchi (OvR) were fermented until the pH reached pH 5.6, pH 4.3, and pH 3.8, respectively. The radical scavenging activity and protective activity from oxidative stress of kimchi during fermentation were investigated under in vitro and cellular systems using LLC-PK1 cells. Kimchi exhibited strong radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, superoxide anion, and hydroxyl radical. In addition, the free radical generators led to loss of cell viability and elevated lipid peroxidation, while treatment with kimchi resulted in significantly increased cell viability and decreased lipid peroxidation. Furthermore, the protective effect against oxidative stress was related to regulation of cyclooxygenase-2, inducible nitric oxide synthase, nuclear factor-κB p65, and IκB expression. In particular, OvR showed the strongest protective effect from cellular oxidative stress among other kimchi. The current study indicated that kimchi, particularly OptR and OvR, played a protective role against free radical-induced oxidative stress. These findings suggest that kimchi is a promising functional food with an antioxidative effect and fermentation of kimchi led to elevation of antioxidative activity.

  5. Chemical Composition, and Antibacterial (against Staphylococcus aureus and Free-Radical-Scavenging Activities of the Essential Oil of Scrophularia amplexicaulis Benth.

    Directory of Open Access Journals (Sweden)

    Ardalan Pasdaran

    2012-07-01

    Full Text Available Chemical composition of the essential oil obtained from the aerial parts of Scrophularia amplexicaulis Benth. was analyzed, for the first time, by the gas chromatography/mass spectrometry (GC-MS and gas chromatography/flame ionization detection (GC-FID. A total yield of 3 mg of essential oil per100 g of plant dry mass was obtained, and 27 compounds were identified, representing 97. 7 % of total oil. The essential oil were characterized by a high content of oxygenated monoterpenes and phenolic derivatives. The main constituents were eugenol (53.8%, eugenol acetate (24.5%, b -caryophyllene (5.7%, caryophyllene oxide (6.4% and aromadendrene oxide II (2.1%. The antimicrobial activity of the essential oil was tested against Staphylococcus aureus using the well diffusion method, and t he free-radical-scavenging activity was assessed by the 2,2-diphenyl-picryl-hydrazyl (DPPH assay.

  6. EPR studies of free radicals decay and survival in gamma irradiated aminoglycoside antibiotics: sisomicin, tobramycin and paromomycin.

    Science.gov (United States)

    Wilczyński, Sławomir; Pilawa, Barbara; Koprowski, Robert; Wróbel, Zygmunt; Ptaszkiewicz, Marta; Swakoń, Jan; Olko, Paweł

    2012-02-14

    Radiation sterilization technology is more actively used now that any time because of its many advantages. Gamma radiation has high penetrating power, relatively low chemical reactivity and causes small temperature rise. But on the other hand radiosterilization can lead to radiolytic products appearing, in example free radicals. Free radicals in radiative sterilized sisomicin, tobramycin and paromomycin were studied by electron paramagnetic resonance (EPR) spectroscopy. Dose of gamma irradiation of 25kGy was used. Concentrations and properties of free radicals in irradiated antibiotics were studied. EPR spectra were recorded for samples stored in air and argon. For gamma irradiated antibiotics strong EPR lines were recorded. One- and two-exponential functions were fitted to experimental points during testing and researching of time influence of the antibiotics storage to studied parameters of EPR lines. Our study of free radicals in radiosterilized antibiotics indicates the need for characterization of medicinal substances prior to sterilization process using EPR values. We propose the concentration of free radicals and other spectroscopic parameters as useful factors to select the optimal type of sterilization for the individual drug. The important parameters are i.a. the τ time constants and K constants of exponential functions. Time constants τ give us information about the speed of free radicals concentration decrease in radiated medicinal substances. The constant K(0) shows the free radicals concentration in irradiated medicament after long time of storage. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  8. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  9. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  10. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  11. Free radical-mediated hydroxymethylation using CO and HCHO.

    Science.gov (United States)

    Kawamoto, Takuji; Ryu, Ilhyong

    2012-01-01

    Tin-free radical hydroxymethylations of haloalkanes using CO and HCHO as a C1 unit proceed efficiently in the presence of borohydrides as radical mediators. In the approach using CO, the formation of aldehydes by radical carbonylation and their subsequent reduction by hydrides lead to alcohols. On the other hand, the use of formaldehyde is more straightforward, in which the key reaction is alkyl radical addition to formaldehyde to give alkoxy radical, which abstracts hydrogen from borohydride reagents. The cascade sequences were observed in the reaction of cholesteryl bromide with HCHO, which displays the diverse applications of HCHO in radical chemistry.

  12. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  13. Interactions between simple radicals and water

    Energy Technology Data Exchange (ETDEWEB)

    Crespo-Otero, Rachel [Lehrstuhl fuer Organische Chemie II der Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Laboratorio de Quimica Computacional y Teorica, Facultad de Quimica, Universidad de la Habana, 10400 (Cuba); Sanchez-Garcia, Elsa [Lehrstuhl fuer Organische Chemie II der Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)], E-mail: elsa.sanchez@rub.de; Suardiaz, Reynier; Montero, Luis A. [Laboratorio de Quimica Computacional y Teorica, Facultad de Quimica, Universidad de la Habana, 10400 (Cuba); Sander, Wolfram [Lehrstuhl fuer Organische Chemie II der Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)], E-mail: wolfram.sander@rub.de

    2008-11-03

    The interactions of the simple radicals CH{sub 3}, NH{sub 2}, OH, and F with water have been studied by DFT (UB3LYP/6-311++G(2d,2p)) and ab initio (RHF-UCCSD(T)/6-311++G(2d,2p)) methods. In this order the number of lone pairs (from zero to three), the electronegativity, and the strength of the X-H bonds increase (X = C, N, and O). The various minima of the radical-water complexes were located using the multiple minima hypersurface (MMH) approach which had previously been proven to be useful for closed-shell molecules. The role of the unpaired electron in hydrogen bonding was investigated using the natural bond orbital (NBO) analysis. A considerable contribution of the unpaired electron to the complex stabilization was only found for the methyl radical and the fluorine atom, whereas in the aminyl and the hydroxyl radical the role of the unpaired electron is negligible.

  14. Radical irradiation for carcinoma of the prostate

    African Journals Online (AJOL)

    1990-09-15

    Sep 15, 1990 ... 309. Radical irradiation for carcinoma of the prostate. R. P. ABRATT, P. S. CRAIGHEAD, V. B. REDDI,, ... treated by hormones for at least 2 months and who were subsequently irradiated, are also discussed ... Hospital, Port Elizabeth; and Frere Hospital, East London, in. 1979. S Atr MedJ 1990; 78: 309-311.

  15. Free radicals in adolescent varicocele testis.

    Science.gov (United States)

    Romeo, Carmelo; Santoro, Giuseppe

    2014-01-01

    We examine the relationship between the structure and function of the testis and the oxidative and nitrosative stress, determined by an excessive production of free radicals and/or decreased availability of antioxidant defenses, which occur in the testis of adolescents affected by varicocele. Moreover, the effects of surgical treatment on oxidative stress were provided. We conducted a PubMed and Medline search between 1980 and 2014 using "adolescent," "varicocele," "free radicals," "oxidative and nitrosative stress," "testis," and "seminiferous tubules" as keywords. Cross-references were checked in each of the studies, and relevant articles were retrieved. We conclude that increased concentration of free radicals, generated by conditions of hypoxia, hyperthermia, and hormonal dysfunction observed in adolescent affected by varicocele, can harm germ cells directly or indirectly by influencing nonspermatogenic cells and basal lamina. With regard to few available data in current literature, further clinical trials on the pre- and postoperative ROS and RNS levels together with morphological studies of the cellular component of the testis are fundamental for complete comprehension of the role played by free radicals in the pathogenesis of adolescent varicocele and could justify its pharmacological treatment with antioxidants.

  16. Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic ...

    African Journals Online (AJOL)

    Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic Profile of Methanol Extracts of Wild Plants of Southern Sonora, Mexico. EF Moran-Palacio, LA Zamora-Álvarez, NA Stephens-Camacho, GA Yáñez- Farías, A Virgen-Ortiz, O Martínez-Cruz, JA Rosas-Rodríguez ...

  17. Radical Scavenging, Antimicrobial and Insecticidal Efficacy of ...

    African Journals Online (AJOL)

    Lichens are self-supporting symbiotic association of mycobiont and photobiont. The present study was conducted to investigate antimicrobial, insecticidal and radical scavenging potential of methanol extract of two macrolichens viz. Parmotrema cristiferum (Taylor) Hale and Dirinaria applanata (Fée) D.D. Awasthi.

  18. Parents’ Perspectives on Radicalization: A Qualitative Study

    NARCIS (Netherlands)

    E. Sikkens (Elga); M.R.P.J.R.S. van San (Marion); S. Sieckelinck (Stijn); M. de Winter (Micha)

    2018-01-01

    textabstractAbstract: Radicalization of young people might be influenced by the way parents react towards the development of political or religious ideals. However, these reactions have hardly been explored. This study aimed to discover how parents reacted to the development of extreme ideals, and

  19. Radical recombinations in acetylene-air flames

    NARCIS (Netherlands)

    Zeegers, P.J.Th.; Alkemade, C.T.J.

    In this paper an analysis is given of the behaviour of excess radical concentrations, H, OH and O as a function of height above the reaction zone in premixed acetylene-air flames at 2–200° to 2400°K and 1 atmosphere pressure. The intensity was measured of the Li resonance line which is related to

  20. Short Communication Radical Scavenging Activity and Preliminary ...

    African Journals Online (AJOL)

    Bheema

    Cassia arereh is traditionally used as a fish poison and to manage different disease conditions including gastrointestinal tract (GIT) disorders, ... growth of pathogenic bacteria. These events are often associated with the termination of free radical propagation in biological systems. Accordingly, the antioxidant capacity is ...

  1. Quantification of Radicals Generated in a Sonicator

    Directory of Open Access Journals (Sweden)

    Kassim Badmus

    2016-06-01

    Full Text Available The hydroxyl radical (OH• is a powerful oxidant produced as a consequence of cavitation in water. It can react nonspecifically in breaking down persistent organic pollutants in water into their mineral form. It can also recombine to form hydrogen peroxide which is very useful in water treatment. In this study, terephthalic acid (TA and potassium iodide dosimetry were used to quantify and investigate the behaviour of the generated OH radical in a laboratory scale sonicator. The 2-hydroxyl terephthalic acid (HTA formed during terephthalic acid dosimetry was determined by optical fibre spectrometer. The production rate of HTA served as a means of evaluating and characterizing the OH• generated over given time in a sonicator. The influence of sonicator power intensity, solution pH and irradiation time upon OH• generation were investigated. Approximately 2.2 ´ 10-9 M s-1 of OH radical was generated during the sonication process. The rate of generation of the OH radicals was established to be independent of the concentration of the initial reactant. Thus, the rate of generation of OH• can be predicted by zero order kinetics in a sonicator.

  2. Lipophilic fluorescent products of free radicals

    Czech Academy of Sciences Publication Activity Database

    Ivica, Josko; Wilhelm, Jiří

    2014-01-01

    Roč. 158, č. 3 (2014), s. 365-372 ISSN 1213-8118 R&D Projects: GA ČR(CZ) GAP303/11/0298 Institutional support: RVO:67985823 Keywords : lipofuscin-like pigments * lipid peroxidation * free radicals * fluorescence Subject RIV: CE - Biochemistry Impact factor: 1.200, year: 2014

  3. Long term complications after radical cystoprostatectomy with ...

    African Journals Online (AJOL)

    A. Shelbaia

    A total of 44 male patients underwent radical cystectomy and orthotopic diversion (W-pouch) for invasive bladder cancer with minimum follow up 1 year. Assessment ... The tools used to assess the complications during each visit included; history including voiding diary ... and mortality rates in both males and females [3].

  4. User involvement competence for radical innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher

    2007-01-01

    -assisted navigation systems. The case study analysis reveals that firms who closely interact with specific users benefit significantly for their radical innovation work. These users have a high motivation toward new solutions, are open to new technologies, possess diverse competencies, and are embedded into a very...

  5. Albert Einstein: Radical Pacifist and Democrat

    Science.gov (United States)

    Jayaraman, T.

    We draw attention here to the radical political grounding of Einstein's pacifism. We also drescribe some less commonly known aspects of his commitment to civil liberties, particularly in the context of the anti-l hysteria and anti-racism current in the United States of the late 1940s and 1950s. We also examine briefly his views on socialism.

  6. Radical Negativity: Music Education for Social Justice

    Science.gov (United States)

    McLaren, Peter

    2011-01-01

    According to Hedges (2010), the real enemies of the liberal class are radical thinkers such as Noam Chomsky and Ralph Nader, iconoclastic intellectuals who possess the moral autonomy to defy the power elite. While this author agrees with Hedges, he would take this argument even further. In this article, the author argues that the real enemy of…

  7. Laparoscopic radical trachelectomy: technique, feasibility, and outcomes.

    Science.gov (United States)

    Saadi, José Martín; Perrotta, Myriam; Orti, Roberto; Salvo, Gloria; Giavedoni, María Eugenia; Gogorza, Sebastían; Testa, Roberto

    2015-01-01

    Our objectives are to describe our surgical technique for laparoscopic radical trachelectomy, to evaluate its feasibility, and to present the perioperative results at Hospital Italiano de Buenos Aires, Argentina. We analyzed 4 patients who underwent laparoscopic radical trachelectomy for early-stage cervical cancer between December 2011 and May 2013. Four patients were included in this study. Total laparoscopic radical trachelectomy was performed in all cases. The mean age was 26 years (range, 19-32 years), the mean body mass index was 21 (range, 18-23), and the mean length of hospital stay was 33 hours (range, 24-36 hours). The mean operative time was 225 minutes (range, 210-240 minutes), and no complications were reported. During the postoperative period, only 1 patient presented with left vulvar edema, which resolved spontaneously. The pelvic and parametrial lymph nodes, as well as the vaginal cuff and cervical resection margins, were negative for malignancy in all cases. On average, 18 pelvic lymph nodes (range, 15-20) were removed. The tumor stage was IB in all 4 patients, and the mean tumor size was 17 mm (range, 12-31 mm). No patient required conversion to laparotomy. We consider laparoscopic radical trachelectomy, performed by trained surgeons, a feasible and safe therapeutic option as a fertility-sparing surgical technique, with good perioperative outcomes for women with early-stage cervical cancer with a desire to preserve their fertility. Minimally invasive surgery provides the widely known benefits of this type of approach.

  8. Phytochemical screening, free radical scavenging and antibacterial ...

    African Journals Online (AJOL)

    Cassia sieberiana is a tropical plant, widely distributed throughout Sudan and Guinea savannah. It is used in traditional medicine for the treatment of malarial, cancer and stomach ache. The study was conducted to screen for phytochemicals, free radical scavenging and antibacterial potentials of the root bark.

  9. Postoperative hypertension following radical neck dissection

    Directory of Open Access Journals (Sweden)

    Smita Prakash

    2012-01-01

    Full Text Available Baroreflex failure results in wide excursions of blood pressure and heart rate. We report two cases that developed severe postoperative hypertension after radical neck dissection. Carotid sinus denervation during neck dissection may be the cause of the reflex hypertension once general anesthesia-induced vasodilatation has ended.

  10. Globins Scavenge Sulfur Trioxide Anion Radical*

    Science.gov (United States)

    Gardner, Paul R.; Gardner, Daniel P.; Gardner, Alexander P.

    2015-01-01

    Ferrous myoglobin was oxidized by sulfur trioxide anion radical (STAR) during the free radical chain oxidation of sulfite. Oxidation was inhibited by the STAR scavenger GSH and by the heme ligand CO. Bimolecular rate constants for the reaction of STAR with several ferrous globins and biomolecules were determined by kinetic competition. Reaction rate constants for myoglobin, hemoglobin, neuroglobin, and flavohemoglobin are large at 38, 120, 2,600, and ≥ 7,500 × 106 m−1 s−1, respectively, and correlate with redox potentials. Measured rate constants for O2, GSH, ascorbate, and NAD(P)H are also large at ∼100, 10, 130, and 30 × 106 m−1 s−1, respectively, but nevertheless allow for favorable competition by globins and a capacity for STAR scavenging in vivo. Saccharomyces cerevisiae lacking sulfite oxidase and deleted of flavohemoglobin showed an O2-dependent growth impairment with nonfermentable substrates that was exacerbated by sulfide, a precursor to mitochondrial sulfite formation. Higher O2 exposures inactivated the superoxide-sensitive mitochondrial aconitase in cells, and hypoxia elicited both aconitase and NADP+-isocitrate dehydrogenase activity losses. Roles for STAR-derived peroxysulfate radical, superoxide radical, and sulfo-NAD(P) in the mechanism of STAR toxicity and flavohemoglobin protection in yeast are suggested. PMID:26381408

  11. EPR examination of free radical properties of DOPA-melanin complexes with ciprofloxacin, lomefloxacin, norfloxacin and sparfloxacin

    Science.gov (United States)

    Beberok, Artur; Buszman, Ewa; Zdybel, Magdalena; Pilawa, Barbara; Wrześniok, Dorota

    2010-09-01

    Paramagnetic complexes of DOPA-melanin with ciprofloxacin, lomefloxacin, norfloxacin and sparfloxacin were studied by EPR spectroscopy. The aim of this work was to determine free radical concentration and properties of these complexes. Free radical concentrations in the studied complexes were ∼1019-1020 spin/g. Relatively lower and similar (5.1-6.6 × 1019 spin/g) free radical concentrations characterized DOPA-melanin complexes with ciprofloxacin, and lomefloxacin. Higher concentrations (0.8-1.2 × 1020 spin/g) were obtained for complexes of norfloxacin and sparfloxacin. Effect of the drug concentration on free radicals in melanin was observed. Strong dipolar spin-spin interactions and slow spin-lattice relaxation processes exist in all of the samples.

  12. In vitro antioxidant and free radical scavenging activity of Leonurus ...

    African Journals Online (AJOL)

    The total phenolic compounds in the extracts were determined as gallic acid equivalents, and total flavonoid contents were calculated as quercetin equivalents from a calibration curve. Keywords: Antioxidant activity, Fe2+ chelating, 1,1-diphenyl-2-picryl hydrazyl (DPPH), phenol, Leonurus cardiaca, Grammosciadium ...

  13. Monolignol radical-radical coupling networks in western red cedar and Arabidopsis and their evolutionary implications

    Science.gov (United States)

    Kim, Myoung K.; Jeon, Jae-Heung; Davin, Laurence B.; Lewis, Norman G.

    2002-01-01

    The discovery of a nine-member multigene dirigent family involved in control of monolignol radical-radical coupling in the ancient gymnosperm, western red cedar, suggested that a complex multidimensional network had evolved to regulate such processes in vascular plants. Accordingly, in this study, the corresponding promoter regions for each dirigent multigene member were obtained by genome-walking, with Arabidopsis being subsequently transformed to express each promoter fused to the beta-glucuronidase (GUS) reporter gene. It was found that each component gene of the proposed network is apparently differentially expressed in individual tissues, organs and cells at all stages of plant growth and development. The data so obtained thus further support the hypothesis that a sophisticated monolignol radical-radical coupling network exists in plants which has been highly conserved throughout vascular plant evolution.

  14. Study of radical processes in amino acids and peptides containing thioether group induced by hydroxyl radicals

    International Nuclear Information System (INIS)

    Pogocki, D.M.

    1996-01-01

    Results of investigations of the OH-induced oxidation of amino acids and peptides containing thioether group are presented. Experiments have been carried out over pH range (0-10.5), employing pulse radiolysis and steady-state γ-radiolysis together with a gas-chromatography (GC), a high-performance ionic chromatography (HPICE), and electron spin resonance (ESR) techniques. A general OH-induced oxidation mechanism of these compounds has been proposed, with a hydroxysulfuranyl radical as a primary product formed by an addition of a hydroxyl radical to the thioether group. Secondary reactions of hydroxysulfuranyl radical are dependent on the geometry of the amino acid/peptide molecule, the number of functionalities and on the concentration of the amino acid/peptide and protons in the solutions. Transient products have been identified spectroscopically together with kinetic parameters of some radical reactions. Carbon dioxide acetaldehyde have been also identified as a final products. (author)

  15. TRANSITION METAL CATALYSIS IN CONTROLLED RADICAL POLYMERIZATION: ATOM TRANSFER RADICAL POLYMERIZATION. (R826735)

    Science.gov (United States)

    Novel and diversified macromolecular structures, which include polymers with designed topologies (top), compostions (middle), and functionalities (bottom), can be prepared by atom transfer radical polymerization processes. These polymers can be synthesized from a large variety of...

  16. Antioxidant and Free Radical Scavenging Activity of Trigonella foenum-graecum L, Murraya koenigii , Coriandrum sativum and Centella asiatica

    Directory of Open Access Journals (Sweden)

    Sanghamitra Dutta

    2016-04-01

    Full Text Available Antioxidants are naturally occurring substances that combat oxidative damage in biological entities. An antioxidant achieves this by slowing or preventing the oxidation process that can damage cells in the body. It does this by getting oxidized itself in place of the cells. The aim of the present study was to evaluate the in vitro antioxidant and free radical scavenging activities of aqueous and 95% methanol leaf extracts of four herbs viz. Trigonella foenum-graecum L, Murraya koenigii, Coriandrum sativum and Centella asiatica which have frequent use in Indian cuisine. Both aqueous and 95% methanol leaf extracts have shown significant amount reducing power. Both aqueous and 95% methanol leaf extracts of Coriandrum sativum had significant DPPH radical scavenging activity with IC50 value of 0.21± 0.3 mg/L and 0.176 ± 0.008 mg/L respectively. The aqueous leaf extract of Trigonella foenum-graecum L showed low scavenging activity. Among all the leaf extracts, the aqueous leaf extract of Centella asiatica has exhibited significantly high NO radical scavenging activity (80% with IC50 value of 0.11 ± 0.17 mg/L. The aqueous leaf extracts of the samples have showed significantly high superoxide radical scavenging activity. The activity was maximum for the aqueous leaf extract of Centella asiatica, IC50 value is 4.36 ± 0.41 mg/L. anti lipid peroxide activities were very high ( 90 % for aqueous leaf extracts of Coriandrum sativum (IC50 = 0.064 ± 0.85 mg/L and Centella asiatica (IC50 = 0.066 ± 0.9mg/L at a concentration of 0.16 mg/L. The aqueous leaf extracts of the samples were found to contain large amounts of flavonoids and phenolic compounds and exhibited high antioxidant and free radical scavenging activities. These in vitro assays indicate that these plant extracts are significant source of natural antioxidants which might be helpful in preventing the progress of various oxidative stresses.

  17. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  18. Strongly Interacting Light Dark Matter

    Directory of Open Access Journals (Sweden)

    Sebastian Bruggisser, Francesco Riva, Alfredo Urbano

    2017-09-01

    Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.

  19. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  20. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented