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Sample records for isomeric diglycosyl flavonoids

  1. Silver complexation and tandem mass spectrometry for differentiation of isomeric flavonoid diglycosides.

    Science.gov (United States)

    Zhang, Junmei; Brodbelt, Jennifer S

    2005-03-15

    For detection and differentiation of isomeric flavonoids, electrospray ionization mass spectrometry is used to generate silver complexes of the type (Ag + flavonoid)+. Collisionally activated dissociation (CAD) of the resulting 1:1 silver/flavonoid complexes allows isomer differentiation of flavonoids. Eighteen flavonoid diglycosides constituting seven isomeric series are distinguishable from each other based on the CAD patterns of their silver complexes. Characteristic dissociation pathways allow identification of the site of glycosylation, the type of disaccharide (rutinose versus neohesperidose), and the type of aglycon (flavonol versus flavone versus flavanone). This silver complexation method is more universal than previous metal complexation methods, as intense silver complexes are observed even for flavonoids that lack the typical metal chelation sites. To demonstrate the feasibility of using silver complexation and tandem mass spectrometry to characterize flavonoids in complex mixtures, flavonoids extracted from grapefruit juice are separated by high-performance liquid chromatography and analyzed via a postcolumn complexation ESI-MS/MS strategy. Diagnostic fragmentation pathways of the silver complexes of the individual eluting flavonoids allow successful identification of the six flavonoids in the extract.

  2. Diglycosyl diselenides alter redox homeostasis and glucose consumption of infective African trypanosomes

    Directory of Open Access Journals (Sweden)

    Jaime Franco

    2017-12-01

    Full Text Available With the aim to develop compounds able to target multiple metabolic pathways and, thus, to lower the chances of drug resistance, we investigated the anti-trypanosomal activity and selectivity of a series of symmetric diglycosyl diselenides and disulfides. Of 18 compounds tested the fully acetylated forms of di-β-D-glucopyranosyl and di-β-D-galactopyranosyl diselenides (13 and 15, respectively displayed strong growth inhibition against the bloodstream stage of African trypanosomes (EC50 0.54 μM for 13 and 1.49 μM for 15 although with rather low selectivity (SI < 10 assayed with murine macrophages. Nonacetylated versions of the same sugar diselenides proved to be, however, much less efficient or completely inactive to suppress trypanosome growth. Significantly, the galactosyl (15, and to a minor extent the glucosyl (13, derivative inhibited glucose catabolism but not its uptake. Both compounds induced redox unbalance in the pathogen. In vitro NMR analysis indicated that diglycosyl diselenides react with glutathione, under physiological conditions, via formation of selenenylsulfide bonds. Our results suggest that non-specific cellular targets as well as actors of the glucose and the redox metabolism of the parasite may be affected. These molecules are therefore promising leads for the development of novel multitarget antitrypanosomal agents. Keywords: Glutathione, Redox biosensor, Selenosugar, Trypanosome inhibition, Selenium NMR

  3. Structure Activity Relationships of N-linked and Diglycosylated Glucosamine-Based Antitumor Glycerolipids

    Directory of Open Access Journals (Sweden)

    Makanjuola Ogunsina

    2013-12-01

    Full Text Available 1-O-Hexadecyl-2-O-methyl-3-O-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (1 was previously reported to show potent in vitro antitumor activity on a range of cancer cell lines derived from breast, pancreas and prostate cancer. This compound was not toxic to mice and was inactive against breast tumor xenografts in mice. This inactivity was attributed to hydrolysis of the glycosidic linkage by glycosidases. Here three N-linked (glycosylamide analogs 2–4, one triazole-linked analog 5 of 1 as well as two diglycosylated analogs 6 and 7 with different stereochemistry at the C2-position of the glycerol moiety were synthesized and their antitumor activity against breast (JIMT-1, BT-474, MDA-MB-231, pancreas (MiaPaCa2 and prostrate (DU145, PC3 cancer cell lines was determined. The diglycosylated analogs 1-O-hexadecyl-2(R-, 3-O-di-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (7 and the 1:1 diastereomeric mixture of 1-O-hexadecyl-2(R/S, 3-O-di-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (6 showed the most potent cytotoxic activity at CC50 values of 17.5 µM against PC3 cell lines. The replacement of the O-glycosidic linkage by a glycosylamide or a glycosyltriazole linkage showed little or no activity at highest concentration tested (30 µM, whereas the replacement of the glycerol moiety by triazole resulted in CC50 values in the range of 20 to 30 µM. In conclusion, the replacement of the O-glycosidic linkage by an N-glycosidic linkage or triazole-linkage resulted in about a two to three fold loss in activity, whereas the replacement of the methoxy group on the glycerol backbone by a second glucosamine moiety did not improve the activity. The stereochemistry at the C2-position of the glycero backbone has minimal effect on the anticancer activities of these diglycosylated analogs.

  4. Xylene isomerization

    KAUST Repository

    Bilaus, Rakan Sulaiman; Pinnau, Ingo

    2016-01-01

    at isomenzation conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomenzation can also be coupled with a p

  5. Xylene isomerization

    KAUST Repository

    Bilaus, Rakan Sulaiman

    2016-06-23

    A process for producing xylenes, in particular para-xylene that is less energy intensive than conventional processes is provided. In an embodiment the process comprises contacting a feed mixture in an isomenzation zone with a catalyst at isomenzation conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomenzation can also be coupled with a p-xylene extraction process, where the raffinate (p-xylene deprived stream) from the extraction process is fed to an isomenzation reactor to produce p-xylene. In an embodiment, the process can comprise: a) providing a feed stream comprising a mixture of xylene isomers including p-xylene; b) extracting p-xylene from the feed stream using a separator to separate the feed stream into a p-xylene rich stream and a p-xylene deprived stream; and c) delivering the p-xylene deprived stream to an isomenzation unit, the isomenzation unit including an acidic sulfonated catalytic membrane, and using the isomenzation unit to produce an isomerized product comprising a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomenzation unit. In any one or more aspects, the isomenzation unit can be operated at a temperature in the range of less than 350°, for example about 20°C to about 200°C.

  6. Isomeric Targets and Beams

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Karamyan, S.A.

    1994-01-01

    One of the main topics of modern nuclear physics is the investigation of exotic nuclei including hyper-nuclei, trans fermium elements, proton and neutron rich isotopes near drip lines as well as high-spin excited states and states with anomalous deformation. The isomerism of nuclei is closely related with such phenomena as the alignment of single-particle orbitals, the coexistence of various deformations and the manifestation of intruder-levels from neighbouring shells. The investigation of electromagnetic and nuclear interactions of isomers could give important information on their shell structure and its role in the mechanism of nuclear reactions. For such experiments one can either make isomeric targets (sufficiently long-lived) or use the methods of acceleration of isomeric nuclei. Recently, an exotic 16 + four-quasiparticle isomer of 178 Hf m 2 was produced in a micro weight quantity and the first nuclear reactions on it were successfully observed. The talk describes these experiments as well as new ideas for the continuation of the studies and some advantageous ways for the isomeric beams production by the method of direct acceleration or by the secondary beam method. 35 refs., 15 figs., 8 tabs

  7. Antioxidative properties of flavonoids

    NARCIS (Netherlands)

    Bowedes, T.C.F.; Luttikhold, J.; Stijn, van M.F.M.; Visser, M.; Norren, van K.; Vermeulen, M.A.R.; Leeuwen, P.A.M.

    2011-01-01

    Evidence accumulates that a family of plant compounds, known as flavonoids, can prevent or slow down the progression of cardiovascular diseases, cancer, inflammatory and neurodegenerative diseases. Flavonoids are considered beneficial, this is often attributed to their powerful antioxidant

  8. Isomers chart; Table des isomeres

    Energy Technology Data Exchange (ETDEWEB)

    Dupont-Gautier, P; Chantelot, S; Moisson, N [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    The nuclear isomers are nuclides offering the same mass number and the same atomic number, but different energy levels. In the following chart the zero energy ground states are omitted and the metastable isomers, i.e. of non-zero energy, known and of measurable lifetime, are listed. The lower limit of this lifetime was set here to 0.1 x 10{sup -6} s. The various isomers were classified in increasing lifetimes. (authors) [French] Les isomeres nucleaires sont des nucleides presentant le meme nombre de masse et le meme numero atomique, mais des niveaux energetiques differents. Dans la table suivante, on a neglige les etats fondamentaux d'energie nulle et on a recense les isomeres metastables, c'est-a-dire d'energie non nulle, connus et de periode mesurable. La limite inferieure de cette periode a ete fixee ici a 0,1 x 10{sup -6} s. Les differents isomeres ont ete classes par periodes croissantes. (auteurs)

  9. Isomers chart; Table des isomeres

    Energy Technology Data Exchange (ETDEWEB)

    Dupont-Gautier, P.; Chantelot, S.; Moisson, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    The nuclear isomers are nuclides offering the same mass number and the same atomic number, but different energy levels. In the following chart the zero energy ground states are omitted and the metastable isomers, i.e. of non-zero energy, known and of measurable lifetime, are listed. The lower limit of this lifetime was set here to 0.1 x 10{sup -6} s. The various isomers were classified in increasing lifetimes. (authors) [French] Les isomeres nucleaires sont des nucleides presentant le meme nombre de masse et le meme numero atomique, mais des niveaux energetiques differents. Dans la table suivante, on a neglige les etats fondamentaux d'energie nulle et on a recense les isomeres metastables, c'est-a-dire d'energie non nulle, connus et de periode mesurable. La limite inferieure de cette periode a ete fixee ici a 0,1 x 10{sup -6} s. Les differents isomeres ont ete classes par periodes croissantes. (auteurs)

  10. Experimental grounds for nuclear shape isomerism

    International Nuclear Information System (INIS)

    Makarenko, V.E.

    1995-11-01

    Experimental data on fission isomeric states of actinide nuclei - half lives, energies, quantum numbers, decay branches and spectroscopic properties - are discussed. Quite a few results find their explanation in the framework of nuclear shape isomerism hypothesis being the in-thing for about thirty years. Others seem to be the hints to the quasiparticle nature of fission isomers. The problem could be solved by direct measurement of nuclear spin for isomeric states. (author). 44 refs, 1 tab

  11. Quantum optimal control of ozone isomerization

    International Nuclear Information System (INIS)

    Artamonov, Maxim; Ho, Tak-San; Rabitz, Herschel

    2004-01-01

    We present a feasibility study of ozone isomerization based on a recent ab initio potential energy surface and a model Hamiltonian constructed by holding the bond lengths constant and using the valence angle as the isomerization coordinate. Optimal control theory is used to find an electric field that drives isomerization with a yield of 95% to the symmetric metastable triangular form of ozone. A frequency filter is applied as an additional spectral constraint limiting the field bandwidth. A post-facto analysis is performed showing a degree of inherent robustness of the isomerization yield to field noise

  12. Experiments with neutron-rich isomeric beams

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Lewitowicz, M.; Pfuetzner, M.

    1998-01-01

    A review of experimental results obtained on microsecond-isomeric states in neutron-rich nuclei produced in fragmentation reactions and studied with SISSI-Alpha-LISE3 spectrometer system at GANIL Caen is given. The perspectives of experiments based on secondary reactions with isomeric beams are presented

  13. Flavonoids and the CNS

    DEFF Research Database (Denmark)

    Jäger, Anna Katharina; Saaby, Lasse

    2011-01-01

    Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on their structure....... Flavonoids are present in food and medicinal plants and are thus consumed by humans. They are found in plants as glycosides. Before oral absorption, flavonoids undergo deglycosylation either by lactase phloridzin hydrolase or cytosolic ß-glucocidase. The absorbed aglycone is then conjugated by methylation......, sulphatation or glucuronidation. Both the aglycones and the conjugates can pass the blood-brain barrier. In the CNS several flavones bind to the benzodiazepine site on the GABA(A)-receptor resulting in sedation, anxiolytic or anti-convulsive effects. Flavonoids of several classes are inhibitors of monoamine...

  14. Diurnal changes in flavonoids

    International Nuclear Information System (INIS)

    Veit, M.; Bilger, W.; Mühlbauer, T.; Brummet, W.; Winter, K.

    1996-01-01

    Field studies of a tropical tree, Anacardium excelsum, and a northern hemisphere high altitude fern, Cryptogramma crispa, revealed marked diurnal changes in soluble flavonoid content of leaves and fronds, respectively. The flavonoid content increased during the morning and decreased during the afternoon. In plants of C. crispa covered with UV-B absorbing filters, the flavonoid content remained at a constant level throughout the day/night cycle. Upon removal of UV-B absorbing filters (at night), the flavonoid content increased the next morning in a fashion similar to that observed in control plants maintained without filters. Decreases in photosystem II photochemical efficiency upon exposure of C. crispa to natural daylight were similar in plants previously covered with UV-B absorbing filters and in control plants, probably owing to the observed ability of plants to rapidly accumulate UV-B protective flavonoids. (author)

  15. Flavonoids and the CNS

    Directory of Open Access Journals (Sweden)

    Anna K. Jäger

    2011-02-01

    Full Text Available Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on their structure. Flavonoids are present in food and medicinal plants and are thus consumed by humans. They are found in plants as glycosides. Before oral absorption, flavonoids undergo deglycosylation either by lactase phloridzin hydrolase or cytosolic β-glucocidase. The absorbed aglycone is then conjugated by methylation, sulphatation or glucuronidation. Both the aglycones and the conjugates can pass the blood-brain barrier. In the CNS several flavones bind to the benzodiazepine site on the GABAA-receptor resulting in sedation, anxiolytic or anti-convulsive effects. Flavonoids of several classes are inhibitors of monoamine oxidase A or B, thereby working as anti-depressants or to improve the conditions of Parkinson’s patients. Flavanols, flavanones and anthocyanidins have protective effects preventing inflammatory processes leading to nerve injury. Flavonoids seem capable of influencing health and mood.

  16. Recent patents on flavonoids.

    Science.gov (United States)

    Mamta, Gokhale; Bansal, Y K; Sandhu, S S

    2013-12-01

    Flavonoids are substances which are widely distributed in the plant kingdom. They occur in considerable quantities in common food products, spices and beverages. Interest of researchers has been greatly enhanced towards therapeutic potential of flavonoids in last some years. This review summarizes important patents pertaining to recent biotechnological techniques applied for the production, analysis of biosynthetic pathways, effects and applications of different flavonoids. For systematic studies investigations which have been published in the form of patents, are classified in different sectors like biosynthesis, medical application, antimicrobial activity, alteration of flower color, industrial application, cosmetics, food and plant tissue culture. A number of activities have been observed in each sector with vast area of research on flavonoids.

  17. A new fundamental type of conformational isomerism

    Science.gov (United States)

    Canfield, Peter J.; Blake, Iain M.; Cai, Zheng-Li; Luck, Ian J.; Krausz, Elmars; Kobayashi, Rika; Reimers, Jeffrey R.; Crossley, Maxwell J.

    2018-06-01

    Isomerism is a fundamental chemical concept, reflecting the fact that the arrangement of atoms in a molecular entity has a profound influence on its chemical and physical properties. Here we describe a previously unclassified fundamental form of conformational isomerism through four resolved stereoisomers of a transoid (BF)O(BF)-quinoxalinoporphyrin. These comprise two pairs of enantiomers that manifest structural relationships not describable within existing IUPAC nomenclature and terminology. They undergo thermal diastereomeric interconversion over a barrier of 104 ± 2 kJ mol-1, which we term `akamptisomerization'. Feasible interconversion processes between conceivable synthesis products and reaction intermediates were mapped out by density functional theory calculations, identifying bond-angle inversion (BAI) at a singly bonded atom as the reaction mechanism. We also introduce the necessary BAI stereodescriptors parvo and amplo. Based on an extended polytope formalism of molecular structure and stereoisomerization, BAI-driven akamptisomerization is shown to be the final fundamental type of conformational isomerization.

  18. Easy Synthesis of Two Positional Isomeric Tetrazole Libraries

    NARCIS (Netherlands)

    Wang, Yuanze; Patil, Pravin; Dömling, Alexander

    2016-01-01

    A fast and efficient synthesis of libraries of positional isomeric 1H-tetrazoles and 5H-tetrazoles, for the purpose of testing binding hypothesis of isomeric tetrazoles in fragment-based drug discovery, is described.

  19. Neuroprotection by flavonoids

    Directory of Open Access Journals (Sweden)

    Dajas F.

    2003-01-01

    Full Text Available The high morbidity, high socioeconomic costs and lack of specific treatments are key factors that define the relevance of brain pathology for human health and the importance of research on neuronal protective agents. Epidemiological studies have shown beneficial effects of flavonoids on arteriosclerosis-related pathology in general and neurodegeneration in particular. Flavonoids can protect the brain by their ability to modulate intracellular signals promoting cellular survival. Quercetin and structurally related flavonoids (myricetin, fisetin, luteolin showed a marked cytoprotective capacity in in vitro experimental conditions in models of predominantly apoptotic death such as that induced by medium concentrations (200 µM of H2O2 added to PC12 cells in culture. Nevertheless, quercetin did not protect substantia nigra neurons in vivo from an oxidative insult (6-hydroxydopamine, probably due to difficulties in crossing the blood-brain barrier. On the other hand, treatment of permanent focal ischemia with a lecithin/quercetin preparation decreased lesion volume, showing that preparations that help to cross the blood-brain barrier may be critical for the expression of the effects of flavonoids on the brain. The hypothesis is advanced that a group of quercetin-related flavonoids could become lead molecules for the development of neuroprotective compounds with multitarget anti-ischemic effects.

  20. Flavonoids and Asthma

    Science.gov (United States)

    Tanaka, Toshio; Takahashi, Ryo

    2013-01-01

    Asthma is a chronic disease, characterized by airway inflammation, airflow limitation, hyper-reactivity and airway remodeling. It is believed that asthma is caused by the interaction between genetic and environmental factors. The prevalence of allergic diseases, including asthma, has increased worldwide during the past two decades. Although the precise reasons that have caused this increase remain unknown, dietary change is thought to be one of the environmental factors. Flavonoids, which are polyphenolic plant secondary metabolites ubiquitously present in vegetables, fruits and beverages, possess antioxidant and anti-allergic traits, as well as immune-modulating activities. Flavonoids are powerful antioxidants and anti-allergic nutrients that inhibit the release of chemical mediators, synthesis of Th2 type cytokines, such as interleukin (IL)-4 and IL-13, and CD40 ligand expression by high-affinity immunoglobulin E (IgE) receptor-expressing cells, such as mast cells and basophils. They also inhibit IL-4-induced signal transduction and affect the differentiation of naïve CD4+ T cells into effector T-cells through their inhibitory effect on the activation of the aryl hydrocarbon receptor. Various studies of flavonoids in asthmatic animal models have demonstrated their beneficial effects. The results of several epidemiological studies suggest that an increase in flavonoid intake is beneficial for asthma. Moreover, clinical trials of flavonoids have shown their ameliorative effects on symptoms related to asthma. However, these human studies are currently limited; further validation is required to clarify whether an appropriate intake of flavonoids may constitute dietary treatment and for part of a preventive strategy for asthma. PMID:23752494

  1. Formation, isomerization, and derivatization of keggin tungstoaluminates.

    Science.gov (United States)

    Jennifer J. Cowan; Alan J. Bailey; Robert A. Heintz; Bao T. Do; Kenneth I. Hardcastle; Craig L. Hill; Ira A. Weinstock

    2001-01-01

    Trends in the stability of ¥á and ©¬-Keggin heteropolytungstates of the second-row main-group heteroatoms Al(III), Si(IV), and P(V) are elaborated by data that establish the roles of kinetic and thermodynamic control in the formation and isomerization of Keggin tungstoaluminates. Slow, room-temperature co-...

  2. Isomeric periodic mesoporous organosilicas with controllable properties

    NARCIS (Netherlands)

    Vercaemst, C.; Ide, I.; Friedrich, H.; de Jong, K.P.; Verpoort, F.; van der Voort, P.

    2009-01-01

    The synthesis procedure for isomeric periodic mesoporous organosilicas with E-configured ethenylene bridges was investigated using the homemade pure E-isomer of 1,2-bis(triethoxysilyl)ethene. The pH, aging temperature and the presence of cosolvents played a key role in obtaining well-ordered

  3. Trimethylphosphide isomerization in lanthanum ions presence

    International Nuclear Information System (INIS)

    Zacharias, M.A.; Massabni, A.M.G.

    1984-01-01

    The integration between the trimethilphosphide and the lanthanum ions carry to the formation of solid complexes in a relation of 6:1 where the ligand is the phosphonate what is resultant of the isomerization of trimetylphosphite. By the RMN -1 H and infra-red spectra the products were characterized. (L.M.J.) [pt

  4. Iodine-Catalyzed Isomerization of Dimethyl Muconate

    Energy Technology Data Exchange (ETDEWEB)

    Settle, Amy E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berstis, Laura R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Shuting [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rorrer, Nicholas [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hu, Haiming [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Richards, Ryan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Crowley, Michael F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vardon, Derek R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-12

    cis,cis-Muconic acid is a platform biobased chemical that can be upgraded to drop-in commodity and novel monomers. Among the possible drop-in products, dimethyl terephthalate can be synthesized via esterification, isomerization, Diels-Alder cycloaddition, and dehydrogenation. The isomerization of cis,cis-dimethyl muconate (ccDMM) to the trans,trans-form (ttDMM) can be catalyzed by iodine; however, studies have yet to address (i) the mechanism and reaction barriers unique to DMM, and (ii) the influence of solvent, potential for catalyst recycle, and recovery of high-purity ttDMM. To address this gap, we apply a joint computational and experimental approach to investigate iodine-catalyzed isomerization of DMM. Density functional theory calculations identified unique regiochemical considerations due to the large number of halogen-diene coordination schemes. Both transition state theory and experiments estimate significant barrier reductions with photodissociated iodine. Solvent selection was critical for rapid kinetics, likely due to solvent complexation with iodine. Under select conditions, ttDMM yields of 95% were achieved in <1 h with methanol, followed by high purity recovery (>98%) with crystallization. Lastly, post-reaction iodine can be recovered and recycled with minimal loss of activity. Overall, these findings provide new insight into the mechanism and conditions necessary for DMM isomerization with iodine to advance the state-of-the-art for biobased chemicals.

  5. Crystal structure of isomeric boron difluoride acetylnaphtholates

    International Nuclear Information System (INIS)

    Bukvetskij, B.V.; Fedorenko, E.V.; Mirochnik, A.G.; Karasev, V.E.

    2006-01-01

    Crystal structures of luminescent isomeric acetylnaphtholates of boron difluoride are investigated. Full X-ray structural analysis is done at 293 K. Coordinated of atoms, bond angles, bond lengths, interatomic distances are determined. Results of comparative evaluations of the isomers are represented [ru

  6. Dietary flavonoids and iodine Metabolism

    NARCIS (Netherlands)

    Elst, van der J.P.; Smit, J.W.A.; Romijn, H.A.; Heide, van der D.

    2003-01-01

    Flavonoids have inhibiting effects on the proliferation of cancer cells, including thyroidal ones. In the treatment of thyroid cancer the uptake of iodide is essential. Flavonoids are known to interfere with iodide organification ill vitro, and to cause goiter. The influence of flavonoids on iodine

  7. Cat's claw oxindole alkaloid isomerization induced by common extraction methods

    Directory of Open Access Journals (Sweden)

    Samuel Kaiser

    2013-01-01

    Full Text Available Cat's claw oxindole alkaloids are prone to isomerization in aqueous solution. However, studies on their behavior in extraction processes are scarce. This paper addressed the issue by considering five commonly used extraction processes. Unlike dynamic maceration (DM and ultrasound-assisted extraction, substantial isomerization was induced by static maceration, turbo-extraction and reflux extraction. After heating under reflux in DM, the kinetic order of isomerization was established and equations were fitted successfully using a four-parameter Weibull model (R² > 0.999. Different isomerization rates and equilibrium constants were verified, revealing a possible matrix effect on alkaloid isomerization.

  8. Flavonoids and thyroid disease

    NARCIS (Netherlands)

    Heide, van der D.; Kastelijn, J.; Schroder-van der Elst, J.P.

    2003-01-01

    The most potent natural plant-derived compounds that can affect thyroid function, thyroid hormone secretion and availability to tissues is the group of flavonoids, i.e. plant pigments. They are present in our daily food, such as vegetables, fruits, grains, nuts, wine, and tea. Epidemiological

  9. Flavonoids Fight Diseases

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 2. Flavonoids Fight Diseases. G Nagendrappa. Article-in-a-Box Volume 9 Issue 2 February 2004 pp 5-5. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/02/0005-0005. Author Affiliations.

  10. Is isomerism a risk factor for intestinal volvulus?

    Science.gov (United States)

    Landisch, Rachel M; Loomba, Rohit S; Salazar, Jose H; Buelow, Matthew W; Frommelt, Michele; Anderson, Robert H; Wagner, Amy J

    2018-03-06

    Isomerism, or heterotaxy syndrome, affects many organ systems anatomically and functionally. Intestinal malrotation is common in patients with isomerism. Despite a low reported risk of volvulus, some physicians perform routine screening and prophylactic Ladd procedures on asymptomatic patients with isomerism who are found to have intestinal malrotation. The primary aim of this study was to determine if isomerism is an independent risk factor for volvulus. Kid's Inpatient Database data from 1997 to 2012 was utilized for this study. Characteristics of admissions with and without isomerism were compared with a particular focus on intestinal malrotation, volvulus, and Ladd procedure. A logistic regression was conducted to determine independent risk factors for volvulus with respect to isomerism. 15,962,403 inpatient admissions were included in the analysis, of which 7970 (0.05%) patients had isomerism, and 6 patients (0.1%) developed volvulus. Isomerism was associated with a 52-fold increase in the odds of intestinal malrotation by univariate analysis. Of 251 with isomerism and intestinal malrotation, only 2.4% experienced volvulus. Logistic regression demonstrated that isomerism was not an independent risk factor for volvulus. Isomerism is associated with an increased risk of intestinal malrotation but is not an independent risk factor for volvulus. Prognosis study. Level III. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Characterizing gamma fields using isomeric activation ratios

    Science.gov (United States)

    Venkataraman, Ramkumar; Fleming, Ronald F.

    1994-12-01

    Isomeric activities were induced in indium by gamma irradiation in three different gamma fields, through the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn. The irradiation fields were (i) the 15 kCi 60Co source available in the University, (ii) the spent fuel gamma irradiator in the pool of the University's Ford Nuclear Reactor (FNR) and (iii) south face of the core of the FNR during routine shut downs. Isomeric activation ratios can serve to characterize gamma fields, provided the response functions of the two (γ, γ') reactions sample different energy regimes of the gamma spectrum present in the irradiation fields. The response of an isomeric activation detector, in turn, depends on the number of activation energy levels of the nuclide and the probabilities with which the activation levels de-populate to the isomeric level. The reaction rate ratio RIn115m/ RIn113m was measured in the three gamma fields. The measured ratios were (i) 1.210 ± 0.011 in the 60Co source, (ii) 1.314 ± 0.060 in the spent fuel gamma irradiator and (iii) 1.298 ± 0.039 in a location alongside the FNR core during routine shut downs. The measured reaction rate ratios are not only close to each other, but close to unity as well. This indicates that the excitation functions for the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn have similar shapes and that for the nuclides 115In and 113In, the number of activation energy levels and the probabilities with which they populate the isomeric levels are very similar to each other. Thus, the ratio RIn115m/ RIn113m will not yield any information regarding the shape of gamma spectrum in the field of measurement. However by choosing (γ, γ') reactions with different shapes for the excitation functions one can measure a set of isomeric activation ratios that characterize a given gamma field.

  12. Quercetin: a versatile flavonoid

    Directory of Open Access Journals (Sweden)

    Dr. Deepak Kumar Rai

    2007-07-01

    Full Text Available Associative evidence from observational and intervention studies in human subjects shows that a diet including plant foods (particularly fruit and vegetables rich in antioxidants conveys health benefits. There is no evidence that any particular nutrient or class of bioactive substances makes a special contribution to these benefits. Flavonoids occur naturally in fruits, vegetables and beverages such as tea and wine. Quercetin is the major flavonoid which belongs to the class called flavonols. Quercetin is found in many common foods including apples, tea, onions, nuts, berries, cauliflower, cabbage and many other foods. Quercetin provides many health promoting benefits, including improvement of cardiovascular health, eye diseases, allergic disorders, arthritis, reducing risk for cancers and many more. The main aim of this review is to obtain a further understanding of the reported beneficial health effects of Quercetin, its pharmacological effects, clinical application and also to evaluate its safety.

  13. Flavonoids of Steganotaenia araliacea

    CSIR Research Space (South Africa)

    Omolo, JJ

    2014-01-01

    Full Text Available Communication www.usa-journals.com Omolo, et al., 2014: Vol 2(8) 52 ajrc.journal@gmail.com Flavonoids of Steganotaenia araliacea 1,2,3*Omolo J.J., 2Maharaj V., 2... Communication www.usa-journals.com Omolo, et al., 2014: Vol 2(8) 53 ajrc.journal@gmail.com Introduction The Tanga Aids Working Group (TAWG) in collaboration...

  14. Isomerization of C[sub 4] alkenes

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-11-13

    A method is described for isomerizing isobutene or n-butene to produce a mixture of isobutene and normal butene, and polymerizing at least a portion thereof to produce isobutene/n-butene co-dimer, which comprises feeding at least 80 weight % of either the isobutene or n-butene to a catalytic distillation reactor containing a fixed bed acidic cation exchange resin catalyst packing which provides both the catalyst sites and distillation sites for the reaction products, isomerizing a portion of the isobutene or n-butene to produce a mixture of isobutene and n-butene and reacting at least a portion of the isobutene and n-butene to form co-dimer of isobutene and n-butene, whereby an overhead fraction containing any unreacted isobutene and n-butene and a bottoms fraction containing co-dimer is produced. The result of the reaction is substantially the same regardless whether the feed is isobutene or n-butene. Other aspects of the invention, include combinations of procedures to produce high purity isobutene and n-butene. Either isobutene or n-butene product (depending on the desired product) can be recycled as feed, thus substantially carrying out the isomerization to extinction and total conversion to the desired product. 1 fig.

  15. Thermal E/ Z Isomerization in First Generation Molecular Motors.

    Science.gov (United States)

    Kuwahara, Shunsuke; Suzuki, Yuri; Sugita, Naoya; Ikeda, Mari; Nagatsugi, Fumi; Harada, Nobuyuki; Habata, Yoichi

    2018-04-20

    Determination of a thermal E/ Z isomerization barrier of first generation molecular motors is reported. Stable ( E)-1a directly converts to stable ( Z)-1c without photochemical E/ Z isomerization. The activation Gibbs energy of the isomerization was determined to be 123 kJ mol -1 by circular dichroism spectral changes. Density functional theory calculations show that ( Z)-1c is ∼11.4 kJ mol -1 more stable than ( E)-1a.

  16. The application of HPLC ESI MS in the investigation of the flavonoids and flavonoid glycosides of a Caribbean Lamiaceae plant with potential for bioaccumulation.

    Science.gov (United States)

    Peter, Sonia R; Peru, Kerry M; Fahlman, Brian; McMartin, Dena W; Headley, John V

    2015-01-01

    As part of an exchange technology program between the government of Barbados and Environment Canada, methanolic and aqueous extracts from the flavonoid-rich Lamiaceae family were characterized using negative-ion electrospray mass spectrometry. The species investigated is part of the Caribbean Pharmacopoeia, and is used for a variety of health issues, including colds, flu, diabetes, and hypertension. The extracts were investigated for structural elucidation of phenolics, identification of chemical taxonomic profile, and evidence of bio-accumulator potential. The methanolic and aqueous leaf extracts of Plectranthus amboinicus yielded rosmarinic acid, ladanein, cirsimaritin, and other methoxylated flavonoids. This genus also shows a tendency to form conjugates with monosaccharides, including glucose, galactose, and rhamnose. The aqueous extract yielded four isomeric rhamnosides. The formation of conjugates by Plectranthus amboinicus is thus evidence of high bioaccumulator significance.

  17. Flavonoids from Lonchocarpus muehlbergianus

    Directory of Open Access Journals (Sweden)

    Magalhães Aderbal F.

    2004-01-01

    Full Text Available The light petroleum extract from the roots of Lonchocarpus muehlbergianus Hassl contained nine flavonoids, including six new ones. These are 2,4-cis-2,4,5,8-tetramethoxy-(2,3:6,7-furanoflavan; 2,4-cis-4-hydroxy-2,5,8-trimethoxy-(2,3:6,7-furanoflavan; 2,4-cis-2-prenyloxy-4,5,8-trimethoxy-(2,3:6,7-fu-ranoflavan; 2,4-cis-2-prenyloxy-4-hydroxy-5,8-dimethoxy-(2,3:6,7-furanoflavan; 2',5',6'-trimethoxy-9-(1,1-dimethylallyoxy-[2,3:3,4]-furanochalcone; 5,6-dimethoxy-(2,3:7,8-furanoflavone, identi-fied by analysis of their spectral data (UV, IR, ¹H and 13C NMR, 2D-NMR, NOE and MS. The natural occurrence of 2,4-dioxygenated flavan derivatives is being reported for the first time. Quantitative analysis of the petrol extract, by using reversed-phase HPLC, showed that the most abundant flavonoid in the extract is 2,4-cis-2,4,5,8- tetramethoxy-(2,3:6,7-furanoflavan.

  18. Recent discoveries of anticancer flavonoids.

    Science.gov (United States)

    Raffa, Demetrio; Maggio, Benedetta; Raimondi, Maria Valeria; Plescia, Fabiana; Daidone, Giuseppe

    2017-12-15

    In this review we report the recent advances in anticancer activity of the family of natural occurring flavonoids, covering the time span of the last five years. The bibliographic data will be grouped, on the basis of biological information, in two great categories: reports in which the extract plants bioactivity is reported and the identification of each flavonoid is present or not, and reports in which the anticancer activity is attributable to purified and identified flavonoids from plants. Wherever possible, the targets and mechanisms of action as well as the structure-activity relationships of the molecules will be reported. Also, in the review it was thoroughly investigated the recent discovery on flavonoids containing the 2-phenyl-4H-chromen-4-one system even if some examples of unusual flavonoids, bearing a non-aromatic B-ring or other ring condensed to the base structure are reported. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Designing bifunctional alkene isomerization catalysts using predictive modelling

    NARCIS (Netherlands)

    Landman, I.R.; Paulson, E.R.; Rheingold, A.L.; Grotjahn, D.B.; Rothenberg, G.

    2017-01-01

    Controlling the isomerization of alkenes is important for the manufacturing of fuel additives, fine-chemicals and pharmaceuticals. But even if isomerization seems to be a simple unimolecular process, the factors that govern catalyst performance are far from clear. Here we present a set of models

  20. Flavonoids from Pseudotsuga menziesii.

    Science.gov (United States)

    Krauze-Baranowska, Mirosława; Sowiński, Paweł; Kawiak, Anna; Sparzak, Barbara

    2013-01-01

    Four O-acylated flavonol glycosides, new in the plant kingdom, were isolated from the needles of Pseudotsuga menziesii. Their structures were established by 1D and 2D NMR and MS data as: daglesioside I [kaempferol 3-O-[2",5"-O-(4''',4(IV)-dihydroxy)-beta-truxinoyl]-alpha-L-arabinofuranoside] (1), daglesioside II [kaempferol 3-O-[2",5"-O-(4"'-hydroxy)-beta-truxinoyl]-alpha-L-arabinofuranoside] (2), daglesioside III [kaempferol 3-O-[2",5"-di-O-(E)-p-coumaroyl]-alpha-L-arabinofuranoside] (3), and daglesioside IV [kaempferol 3-O-[3",6"-di-O-(E)-cinnamoyl]-beta-D-glucopyranoside] (4). In addition, the known flavonoids (E)-tiliroside, (E)-ditiliroside, astragalin (kaempferol 3-O-beta-D-glucopyranoside), isorhamnetin, kaempferol, and quercetin were identified. The cytotoxic activity of compounds 1 and 3 was evaluated towards the HL-60, HeLa, and MDA-MB468 cell lines.

  1. Radioimmunoassay for the citrus bitter principle, naringin, and related flavonoid-7-O-neohesperidosides

    International Nuclear Information System (INIS)

    Jourdan, P.S.; Weiler, E.W.; Mansell, R.L.

    1982-01-01

    An immunoassay for the citrus bitter principle, naringin, and related flavonoid-7-O-neohesperidosides is reported. The assay detects ca. 2 ng of naringin and can be used to quantify this compound in the parts per billion (ppb) range in crude grapefruit juice and extracts of other plant tissues. The antiserum used is highly reactive with the 2-rhamnosyl-1-glucopyranose at the C-7 position but not with e.g. the isomeric 6-rhamnosyl-1-glucopyranose moiety and can, thus, be used to identify the stereochemistry of this disaccharide moiety at the C-7 position of flavanoids. The assay involves a directly iodinated naringin-[ 125 I] as immunotracer. (orig.)

  2. Isomeric Detergent Comparison for Membrane Protein Stability

    DEFF Research Database (Denmark)

    Cho, Kyung Ho; Hariharan, Parameswaran; Mortensen, Jonas S.

    2016-01-01

    and utility, particularly for eukaryotic membrane proteins and membrane protein complexes. Thus, a number of new agents have been devised; some have made significant contributions to membrane protein structural studies. However, few detergent design principles are available. In this study, we prepared meta...... and ortho isomers of the previously reported para-substituted xylene-linked maltoside amphiphiles (XMAs), along with alkyl chain-length variation. The isomeric XMAs were assessed with three membrane proteins, and the meta isomer with a C12 alkyl chain was most effective at maintaining solubility....../stability of the membrane proteins. We propose that interplay between the hydrophile–lipophile balance (HLB) and alkyl chain length is of central importance for high detergent efficacy. In addition, differences in inter-alkyl-chain distance between the isomers influence the ability of the detergents to stabilise membrane...

  3. Optimization of Aqueous Extraction from Kalanchoe pinnata Leaves to Obtain the Highest Content of an Anti-inflammatory Flavonoid using a Response Surface Model.

    Science.gov (United States)

    Dos Santos Nascimento, Luana Beatriz; de Aguiar, Paula Fernandes; Leal-Costa, Marcos Vinicius; Coutinho, Marcela Araújo Soares; Borsodi, Maria Paula Gonçalves; Rossi-Bergmann, Bartira; Tavares, Eliana Schwartz; Costa, Sônia Soares

    2018-05-01

    The medicinal plant Kalanchoe pinnata is a phenolic-rich species used worldwide. The reports on its pharmacological uses have increased by 70% in the last 10 years. The leaves of this plant are the main source of an unusual quercetin-diglycosyl flavonoid (QAR, quercetin arabinopyranosyl rhamnopyranoside), which can be easily extracted using water. QAR possess a strong in vivo anti-inflammatory activity. To optimize the aqueous extraction of QAR from K. pinnata leaves using a three-level full factorial design. After a previous screening design, time (x 1 ) and temperature (x 2 ) were chosen as the two independent variables for optimization. Freeze-dried leaves were extracted with water (20% w/v), at 30°C, 40°C or 50°C for 5, 18 or 30 min. QAR content (determined by HPLC-DAD) and yield of extracts were analyzed. The optimized extracts were also evaluated for cytotoxicity. The optimal heating times for extract yield and QAR content were similar in two-dimensional (2D) surface responses (between 12.8 and 30 min), but their optimal extraction temperatures were ranged between 40°C and 50°C for QAR content and 30°C and 38°C for extract yield. A compromise region for both parameters was at the mean points that were 40°C for the extraction temperature and 18 min for the total time. The optimized process is faster and spends less energy than the previous one (water; 30 min at 55°C); therefore is greener and more attractive for industrial purposes. This is the first report of extraction optimization of this bioactive flavonoid. Copyright © 2018 John Wiley & Sons, Ltd. Copyright © 2018 John Wiley & Sons, Ltd.

  4. Antiartherosclerotic Effects of Plant Flavonoids

    Directory of Open Access Journals (Sweden)

    Shamala Salvamani

    2014-01-01

    Full Text Available Atherosclerosis is the process of hardening and narrowing the arteries. Atherosclerosis is generally associated with cardiovascular diseases such as strokes, heart attacks, and peripheral vascular diseases. Since the usage of the synthetic drug, statins, leads to various side effects, the plants flavonoids with antiartherosclerotic activity gained much attention and were proven to reduce the risk of atherosclerosis in vitro and in vivo based on different animal models. The flavonoids compounds also exhibit lipid lowering effects and anti-inflammatory and antiatherogenic properties. The future development of flavonoids-based drugs is believed to provide significant effects on atherosclerosis and its related diseases. This paper discusses the antiatherosclerotic effects of selected plant flavonoids such as quercetin, kaempferol, myricetin, rutin, naringenin, catechin, fisetin, and gossypetin.

  5. Flavonoid intake and all-cause mortality.

    Science.gov (United States)

    Ivey, Kerry L; Hodgson, Jonathan M; Croft, Kevin D; Lewis, Joshua R; Prince, Richard L

    2015-05-01

    Flavonoids are bioactive compounds found in foods such as tea, chocolate, red wine, fruit, and vegetables. Higher intakes of specific flavonoids and flavonoid-rich foods have been linked to reduced mortality from specific vascular diseases and cancers. However, the importance of flavonoids in preventing all-cause mortality remains uncertain. The objective was to explore the association between flavonoid intake and risk of 5-y mortality from all causes by using 2 comprehensive food composition databases to assess flavonoid intake. The study population included 1063 randomly selected women aged >75 y. All-cause, cancer, and cardiovascular mortalities were assessed over 5 y of follow-up through the Western Australia Data Linkage System. Two estimates of flavonoid intake (total flavonoidUSDA and total flavonoidPE) were determined by using food composition data from the USDA and the Phenol-Explorer (PE) databases, respectively. During the 5-y follow-up period, 129 (12%) deaths were documented. Participants with high total flavonoid intake were at lower risk [multivariate-adjusted HR (95% CI)] of 5-y all-cause mortality than those with low total flavonoid consumption [total flavonoidUSDA: 0.37 (0.22, 0.58); total flavonoidPE: 0.36 (0.22, 0.60)]. Similar beneficial relations were observed for both cardiovascular disease mortality [total flavonoidUSDA: 0.34 (0.17, 0.69); flavonoidPE: 0.32 (0.16, 0.61)] and cancer mortality [total flavonoidUSDA: 0.25 (0.10, 0.62); flavonoidPE: 0.26 (0.11, 0.62)]. Using the most comprehensive flavonoid databases, we provide evidence that high consumption of flavonoids is associated with reduced risk of mortality in older women. The benefits of flavonoids may extend to the etiology of cancer and cardiovascular disease. © 2015 American Society for Nutrition.

  6. Microbial biotransformation of bioactive flavonoids.

    Science.gov (United States)

    Cao, Hui; Chen, Xiaoqing; Jassbi, Amir Reza; Xiao, Jianbo

    2015-01-01

    The bioactive flavonoids are considered as the most important phytochemicals in food, which exert a wide range of biological benefits for human being. Microbial biotransformation strategies for production of flavonoids have attracted considerable interest because they allow yielding novel flavonoids, which do not exist in nature. In this review, we summarize the existing knowledge on the production and biotransformation of flavonoids by various microbes. The main reactions during microbial biotransformation are hydroxylation, dehydroxylation, O-methylation, O-demethylation, glycosylation, deglycosylation, dehydrogenation, hydrogenation, C ring cleavage of the benzo-γ-pyrone system, cyclization, and carbonyl reduction. Cunninghamella, Penicillium, and Aspergillus strains are very popular to biotransform flavonoids and they can perform almost all the reactions with excellent yields. Aspergillus niger is one of the most applied microorganisms in the flavonoids' biotransformation; for example, A. niger can transfer flavanone to flavan-4-ol, 2'-hydroxydihydrochalcone, flavone, 3-hydroxyflavone, 6-hydroxyflavanone, and 4'-hydroxyflavanone. The hydroxylation of flavones by microbes usually happens on the ortho position of hydroxyl group on the A ring and C-4' position of the B ring and microbes commonly hydroxylate flavonols at the C-8 position. The microorganisms tend to hydroxylate flavanones at the C-5, 6, and 4' positions; however, for prenylated flavanones, dihydroxylation often takes place on the C4α=C5α double bond on the prenyl group (the side chain of A ring). Isoflavones are usually hydroxylated at the C-3' position of the B ring by microorganisms. The microbes convert flavonoids to their 7-O-glycosides and 3-O-glycosides (when flavonoids have a hydroxyl moiety at the C-3 position). The demethylation of multimethoxyl flavonoids by microbes tends to happen at the C-3' and C-4' positions of the B ring. Multimethoxyl flavanones and isoflavone are demethylated at

  7. Flavonoids from Teucrium fruticans L.

    Directory of Open Access Journals (Sweden)

    Wanda Kisiel

    2014-01-01

    Full Text Available From aerial parts of Teucrium fncticans L. three flavonoids were isolated and identified as 5-hydroxy-6, 7, 3', 4'-tetramethoxyflavone, 5, 4'-dihydroxy-6, 7, 3'-trimethoxyflavone (cirsilineol and 5, 4'-dihydroxy-6, 7-dimethoxyflavone (cirsimaritin. The former compound was found to be a predominant flavone aglycone constituent of the plant material. This is the first report on the isolation of flavonoids from the plant.

  8. Graphene oxide catalyzed cis-trans isomerization of azobenzene

    Directory of Open Access Journals (Sweden)

    Dongha Shin

    2014-09-01

    Full Text Available We report the fast cis-trans isomerization of an amine-substituted azobenzene catalyzed by graphene oxide (GO, where the amine functionality facilitates the charge transfer from azobenzene to graphene oxide in contrast to non-substituted azobenzene. This catalytic effect was not observed in stilbene analogues, which strongly supports the existence of different isomerization pathways between azobenzene and stilbene. The graphene oxide catalyzed isomerization is expected to be useful as a new photoisomerization based sensing platform complementary to GO-based fluorescence quenching methods.

  9. Insights in the Rhodium-Catalyzed Tandem Isomerization-Hydroformylation of 10-Undecenitrile: Evidence for a Fast Isomerization Regime

    Directory of Open Access Journals (Sweden)

    Lucas Le Goanvic

    2018-04-01

    Full Text Available The tandem isomerization-hydroformylation of 10-undecenitrile (1 into the corresponding linear aldehyde (2 with a Rh-biphephos system was studied and the formation of internal olefin isomers (1-int-x was monitored over time. The existence of an “isomerization phenomenon” was evidenced, where fast isomerization of 1 into up to 70% of 1-int-x followed by fast back-isomerization of 1-int-x into 1 and, in turn, into 2 occurs. This fast dynamic isomerization regime is favored at high syngas pressure (40 bar and low biphephos-to-Rh ratio (5–10, and it is best observed at relatively high catalyst loadings ([1]0/[Rh] ≤ 3000. The latter regime is indeed evanescent, and gives place to a second stage in which isomerization of internal olefins (and eventual conversion into 2 proceeds much more slowly. The results are tentatively rationalized by the formation of an unstable species that promotes dynamic isomerization and which slowly vanishes or collapses into a Rh-biphephos species which is the one responsible for hydroformylation.

  10. Synthesis and Characterisation of Eight Isomeric Bis(2-pyridyloxynaphthalenes

    Directory of Open Access Journals (Sweden)

    Peter J. Steel

    2006-09-01

    Full Text Available Eight isomeric bis(2-pyridyloxynaphthalenes have been prepared from reactions of 2-bromopyridine with the appropriate dihydroxynaphthalene and the products fully characterised by 1- and 2-D NMR spectroscopy.

  11. Isomerizations of the Nitromethane Radical Cation in the Gas Phase

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars; Elbel, Susanne

    1986-01-01

    The concurrent isomerizations of the nitromethane radical cation to its aci-nitromethane and methylnitrite isomers, respectively, has been established based on metastable ion studies and collision activation mass spectrometry. The energy diagram for the ionized nitromethane/aci-nitromethane tauto......The concurrent isomerizations of the nitromethane radical cation to its aci-nitromethane and methylnitrite isomers, respectively, has been established based on metastable ion studies and collision activation mass spectrometry. The energy diagram for the ionized nitromethane...

  12. Structure, bioactivity, and synthesis of methylated flavonoids.

    Science.gov (United States)

    Wen, Lingrong; Jiang, Yueming; Yang, Jiali; Zhao, Yupeng; Tian, Miaomiao; Yang, Bao

    2017-06-01

    Methylated flavonoids are an important type of natural flavonoid derivative with potentially multiple health benefits; among other things, they have improved bioavailability compared with flavonoid precursors. Flavonoids have been documented to have broad bioactivities, such as anticancer, immunomodulation, and antioxidant activities, that can be elevated, to a certain extent, by methylation. Understanding the structure, bioactivity, and bioavailability of methylated flavonoids, therefore, is an interesting topic with broad potential applications. Though methylated flavonoids are widely present in plants, their levels are usually low. Because developing efficient techniques to produce these chemicals would likely be beneficial, we provide an overview of their chemical and biological synthesis. © 2017 New York Academy of Sciences.

  13. Study of the photochemical isomerization of ergosterol

    International Nuclear Information System (INIS)

    Mermet-Bouvier, Rene

    1972-01-01

    The photochemical reaction scheme of Ergosterol-Vitamin D 2 was studied. The schemes proposed in published literature are described together with earlier methods used for the analysis and determination. The method used is then discussed. In the first part, the factors concerning the changes occurring in molecular systems exposed to radiation, and the formalism used, are examined. Investigations of linear molecular systems and their applications to the reaction scheme of Ergosterol-Vitamin D 2 are discussed. The properties which enable the last three reaction schemes proposed in the literature to be distinguished are described. In the second part, the experimental analytical methods and the determinations made of the different isomers formed are presented. Chromatographic techniques (thin films, columns, gaseous phase) suitable for separating the various isomeric species are used. The existence of 8 isomers was established as well as a transformation occurring in one of them. The ultraviolet and infrared spectra were obtained. A reaction scheme is proposed (in which all the quantum yield values are given) from comparisons between the calculated and experimental values of the eigenvalue of the absolute minimum value λ m and the eigenvector corresponding to V m . (author) [fr

  14. Modification of flavonoid biosynthesis in crop plants

    NARCIS (Netherlands)

    Schijlen, E.G.W.M.; Vos, de C.H.; Tunen, van A.J.; Bovy, A.G.

    2004-01-01

    Flavonoids comprise the most common group of polyphenolic plant secondary metabolites. In plants, flavonoids play an important role in biological processes. Beside their function as pigments in flowers and fruits, to attract pollinators and seed dispersers, flavonoids are involved in UV-scavenging,

  15. Analysis and health effects of flavonoids.

    NARCIS (Netherlands)

    Hollman, P.C.H.; Hertog, M.G.L.; Katan, M.B.

    1996-01-01

    Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Over 4000 different flavonoids have been described. Flavonoids have a variety of biological effects in numerous mammalian cell systems, in vitro as well as in vivo. Recently much attention has been paid to their

  16. Flavonoids and terpenoids from Helichrysum forskahlii.

    Science.gov (United States)

    Al-Rehaily, Adnan J; Albishi, Omar A; El-Olemy, Mahmoud M; Mossa, Jaber S

    2008-06-01

    Three new flavonoids, namely helichrysone A (1), helichrysone B (2) and helichrysone C (3) were isolated from the aerial parts of Helichrysum forskahlii, together with 10 known flavonoids, three triterpenes, and one sesquiterpene. The structures of the new flavonoids 1-3 were established by 1D and 2D NMR spectral data. In addition, the antimicrobial activities of the isolated compounds were determined.

  17. Antioxidant activity of banana flavonoids.

    Science.gov (United States)

    Vijayakumar, S; Presannakumar, G; Vijayalakshmi, N R

    2008-06-01

    The antioxidant activity of flavonoids from banana (Musa paradisiaca) was studied in rats fed normal as well as high fat diets. Concentrations of peroxidation products namely malondialdehyde, hydroperoxides and conjugated diens were significantly decreased whereas the activities of catalase and superoxide dismutase were enhanced significantly. Concentrations of glutathione were also elevated in the treated animals.

  18. Improving gasoline quality produced from MIDOR light naphtha isomerization unit

    Directory of Open Access Journals (Sweden)

    M.F. Mohamed

    2017-03-01

    Full Text Available Isomerization process became one of the best gasoline production sources, as it gives a high octane product while saving environment from pollution impacts. This paper presents a practical study that aims to improve the gasoline quality and economic income of an existing light naphtha isomerization unit used for octane improvement. The study included selecting the optimum combination of isomerization unit equipment that gives better product specifications for a specified feed. Eight scenarios were studied and simulated to predict the product specs. The original studied unit is MIDOR light naphtha isomerization unit at Alexandria-Egypt that recycles the unconverted hexane (C6. The other studied scenarios were adding fractionators for separating feed iso-pentanes, and recycling unconverted pentanes, hexanes and/or combinations of these fractionators. The results show a change in octane number of gasoline product for a specific feed. Once through process with no extra fractionators has lower octane number of 81 while that with de-iso-pentanizer–de-pentanizer and de-hexanizer produces gasoline with 92.3 octane number. Detailed economic study was done to calculate the return on investment “ROI” for each process option based on equipment, utilities, feed and product prices. Once through simple isomerization unit had the lowest ROI of 14.3% per year while the combination of De-iso-pentanizer with the De-hexanizer had the best ROI of 26.6% per year.

  19. Radiochemical study of isomerization of free butyl cations

    International Nuclear Information System (INIS)

    Sinotova, E.N.; Nefedov, V.D.; Skorokhodov, S.S.; Arkhipov, Yu.M.

    1987-01-01

    Ion-molecular reactions of free butyl cations, generated by nuclear chemical method, with carbon monoxide containing small quantities of ethanol vapors are studied. Carbon monoxide was used to fix instable butyl cations in the form of corresponding acyl ions. Ester of α-methyl-butyric acid appears to be the only product of free butyl cation interaction with carbon monoxide in the presence of ethanol vapors. That means, that up to the moment of butyl cation reaction with carbon monoxide, the primary butyl cations are almost completely isomerized into secondary in agreement with results of previous investigations. This allows one to study free butyl cation isomerization process according to ion-molecular reaction product isomeric composition

  20. Isomeric states in 253No and 253Fm

    International Nuclear Information System (INIS)

    Antalic, S.; Kalaninova, Z.; Saro, S.; Venhart, M.; Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Khuyagbaatar, J.; Kojouharov, I.; Kuusiniemi, P.; Lommel, B.; Mann, R.; Sulignano, B.; Hofmann, S.; Leino, M.; Nishio, K.; Streicher, B.

    2011-01-01

    Nuclear structure and decay of isomeric states in 253 No were investigated. The isotope was produced by the reaction 48 Ca + 207 Pb. The excitation energy of the known single-particle isomeric state (5/2 + [622]) was measured by delayed coincidences between γ-rays and implanted evaporation residues and was placed into the level scheme. In addition, decay of a high-lying multi-quasiparticle isomer in 253 No was studied using e - -γ coincidence measurements. A rotational band populated by its de-excitation was identified in 253 No. A new isomeric state in 253 Fm was observed and a partial-level scheme for this isotope is suggested. In addition γ transitions from excited levels are reported for 253 Md. (orig.)

  1. Isomerization Intermediates In Solution Phase Photochemistry Of Stilbenes

    Science.gov (United States)

    Doany, F. E.; Hochstrasser, R. M.; Greene, B. I.

    1985-04-01

    Picosecond and subpicosecond spectroscopic studies have revealed evidence for an isomerization intermediate between cis and trans in the photoinduced isomerism of both stilbene and biindanyledene ("stiff" stilbene). In stiff stilbene, a transient absorption at 351 nm displays time evolution and viscosity dependence consistent with absorption by a twisted intermediate ("phantom" state) with a lOps lifetime. An analagous bottleneck state with a life-time of 4ps is also consistent with the ground state recovery dynamics of t-stilbene following excitation of c-stilbene when monitored with 0.1ps resolution.

  2. Evaluation of isomeric excitation functions in neutron induced reactions

    International Nuclear Information System (INIS)

    Grudzevich, O.; Ignatyuk, A.; Zolotarev, K.

    1992-01-01

    The possibilities of isomer levels experimental excitation functions description with theoretical models are discussed. It is shown that the experimental data in many cases can be described by theoretical models quite well without parameter fitting. However, large discrepancies are observed for some reactions. In our opinion, these discrepancies are due to uncertainties of discrete level schemes, schemes of gamma-transitions between levels and spin dependence of level density. Small values of isomeric ratios (< 0.1) have been described with the largest errors. The simple formulae for energy dependence of isomeric ratio for (n,g) reaction has been proposed. (author). 53 refs, 10 figs, 8 tabs

  3. cis–trans Isomerization of silybins A and B

    Directory of Open Access Journals (Sweden)

    Michaela Novotná

    2014-05-01

    Full Text Available Methods were developed and optimized for the preparation of the 2,3-cis- and the 10,11-cis-isomers of silybin by the Lewis acid catalyzed (BF3∙OEt2 isomerization of silybins A (1a and B (1b (trans-isomers. The absolute configuration of all optically pure compounds was determined by using NMR and comparing their electronic circular dichroism data with model compounds of known absolute configurations. Mechanisms for cis–trans-isomerization of silybin are proposed and supported by quantum mechanical calculations.

  4. Evaluation of excitation functions for isomeric levels in neutron reactions

    International Nuclear Information System (INIS)

    Grudzevich, O.T.; Zelenetskij, A.V.; Zolotarev, K.I.; Kornilov, N.V.; Pashchenko, A.B.

    1993-07-01

    The authors consider the use of theoretical models to describe experimental excitation functions for isomeric levels in neutron reactions and to predict the cross-sections when no experimental data are available. It is shown that, in many cases, experimental data can be described quite satisfactorily by calculations without adjustment of parameters. For threshold reactions at a neutron energy of ∼ 14 MeV the agreement between calculated and experimental isomeric ratios is ∼ 20%, and is determined mainly by errors in the experimental ratios. However, for some reactions there are considerable differences between experimental and calculated data, which are due, in the authors' opinion, to uncertainties in the schemes of the low-lying levels and of gamma transitions between levels and to the spin dependence of level density. The small isomeric ratio values R<0.1 are described with the lowest accuracy. A formula is suggested for the energy dependence of the isomeric ratio in the (n,γ) reaction. (author)

  5. cis-trans Isomerization of silybins A and B

    Czech Academy of Sciences Publication Activity Database

    Novotná, Michaela; Gažák, Radek; Biedermann, David; Di Meo, F.; Marhol, Petr; Kuzma, Marek; Bednárová, Lucie; Fuksová, Kateřina; Trouillas, P.; Křen, Vladimír

    -, č. 10 (2014), s. 1047-1063 ISSN 1860-5397 R&D Projects: GA ČR GAP207/10/0288; GA MŠk LH13097; GA MŠk(CZ) LD13041 Institutional support: RVO:61388971 ; RVO:61388963 Keywords : isomerization * silibinin * silybin Subject RIV: CC - Organic Chemistry Impact factor: 2.762, year: 2014

  6. Isomerization of β-carotene by titanium tetrachloride catalyst

    Indian Academy of Sciences (India)

    TECS

    2007-05-04

    May 4, 2007 ... antioxidant because of the presence of a long chain of conjugated carbon-carbon double bonds. ... such as extraction, chromatography etc. It has been reported that the chlorinated solvents can promote isomerization of trans conjugated polyenes such as β-carotene during extraction.5. Also, the isomeriza-.

  7. Isomerization of 2-phospha-4-silabicyclo[1.10]butane

    NARCIS (Netherlands)

    Slootweg, J.C.; Ehlers, A.W.; Lammertsma, K.

    2004-01-01

    In analogy with the valence isomerism of the hydrocarbons bicyclobutane, 1,3-butadiene and cyclobutene, the rearrangements for 2-phospha-4-sila- bicyclo[1.1.0]butane were studied at the B3LYP/6-311+G** level of theory. The monocyclic 1,2-dihydro-1,2-phosphasilete is shown to be the thermodynamically

  8. Flavonoid Bioavailability and Attempts for Bioavailability Enhancement

    Science.gov (United States)

    Thilakarathna, Surangi H.; Rupasinghe, H. P. Vasantha

    2013-01-01

    Flavonoids are a group of phytochemicals that have shown numerous health effects and have therefore been studied extensively. Of the six common food flavonoid classes, flavonols are distributed ubiquitously among different plant foods whereas appreciable amounts of isoflavones are found in leguminous plant-based foods. Flavonoids have shown promising health promoting effects in human cell culture, experimental animal and human clinical studies. They have shown antioxidant, hypocholesterolemic, anti-inflammatory effects as well as ability to modulate cell signaling and gene expression related disease development. Low bioavailability of flavonoids has been a concern as it can limit or even hinder their health effects. Therefore, attempts to improve their bioavailability in order to improve the efficacy of flavonoids are being studied. Further investigations on bioavailability are warranted as it is a determining factor for flavonoid biological activity. PMID:23989753

  9. Cancer chemoprevention through dietary flavonoids: what's limiting?

    Science.gov (United States)

    Amawi, Haneen; Ashby, Charles R; Tiwari, Amit K

    2017-06-19

    Flavonoids are polyphenols that are found in numerous edible plant species. Data obtained from preclinical and clinical studies suggest that specific flavonoids are chemo-preventive and cytotoxic against various cancers via a multitude of mechanisms. However, the clinical use of flavonoids is limited due to challenges associated with their effective use, including (1) the isolation and purification of flavonoids from their natural resources; (2) demonstration of the effects of flavonoids in reducing the risk of certain cancer, in tandem with the cost and time needed for epidemiological studies, and (3) numerous pharmacokinetic challenges (e.g., bioavailability, drug-drug interactions, and metabolic instability). Currently, numerous approaches are being used to surmount some of these challenges, thereby increasing the likelihood of flavonoids being used as chemo-preventive drugs in the clinic. In this review, we summarize the most important challenges and efforts that are being made to surmount these challenges.

  10. Flavonoids: promising natural compounds against viral infections.

    Science.gov (United States)

    Zakaryan, Hovakim; Arabyan, Erik; Oo, Adrian; Zandi, Keivan

    2017-09-01

    Flavonoids are widely distributed as secondary metabolites produced by plants and play important roles in plant physiology, having a variety of potential biological benefits such as antioxidant, anti-inflammatory, anticancer, antibacterial, antifungal and antiviral activity. Different flavonoids have been investigated for their potential antiviral activities and several of them exhibited significant antiviral properties in in vitro and even in vivo studies. This review summarizes the evidence for antiviral activity of different flavonoids, highlighting, where investigated, the cellular and molecular mechanisms of action on viruses. We also present future perspectives on therapeutic applications of flavonoids against viral infections.

  11. Wine Flavonoids in Health and Disease Prevention.

    Science.gov (United States)

    Fernandes, Iva; Pérez-Gregorio, Rosa; Soares, Susana; Mateus, Nuno; de Freitas, Victor

    2017-02-14

    Wine, and particularly red wine, is a beverage with a great chemical complexity that is in continuous evolution. Chemically, wine is a hydroalcoholic solution (~78% water) that comprises a wide variety of chemical components, including aldehydes, esters, ketones, lipids, minerals, organic acids, phenolics, soluble proteins, sugars and vitamins. Flavonoids constitute a major group of polyphenolic compounds which are directly associated with the organoleptic and health-promoting properties of red wine. However, due to the insufficient epidemiological and in vivo evidences on this subject, the presence of a high number of variables such as human age, metabolism, the presence of alcohol, the complex wine chemistry, and the wide array of in vivo biological effects of these compounds suggest that only cautious conclusions may be drawn from studies focusing on the direct effect of wine and any specific health issue. Nevertheless, there are several reports on the health protective properties of wine phenolics for several diseases such as cardiovascular diseases, some cancers, obesity, neurodegenerative diseases, diabetes, allergies and osteoporosis. The different interactions that wine flavonoids may have with key biological targets are crucial for some of these health-promoting effects. The interaction between some wine flavonoids and some specific enzymes are one example. The way wine flavonoids may be absorbed and metabolized could interfere with their bioavailability and therefore in their health-promoting effect. Hence, some reports have focused on flavonoids absorption, metabolism, microbiota effect and overall on flavonoids bioavailability. This review summarizes some of these major issues which are directly related to the potential health-promoting effects of wine flavonoids. Reports related to flavonoids and health highlight some relevant scientific information. However, there is still a gap between the knowledge of wine flavonoids bioavailability and their health

  12. Left cardiac isomerism in the Sonic hedgehog null mouse.

    Science.gov (United States)

    Hildreth, Victoria; Webb, Sandra; Chaudhry, Bill; Peat, Jonathan D; Phillips, Helen M; Brown, Nigel; Anderson, Robert H; Henderson, Deborah J

    2009-06-01

    Sonic hedgehog (Shh) is a secreted morphogen necessary for the production of sidedness in the developing embryo. In this study, we describe the morphology of the atrial chambers and atrioventricular junctions of the Shh null mouse heart. We demonstrate that the essential phenotypic feature is isomerism of the left atrial appendages, in combination with an atrioventricular septal defect and a common atrioventricular junction. These malformations are known to be frequent in humans with left isomerism. To confirm the presence of left isomerism, we show that Pitx2c, a recognized determinant of morphological leftness, is expressed in the Shh null mutants on both the right and left sides of the inflow region, and on both sides of the solitary arterial trunk exiting from the heart. It has been established that derivatives of the second heart field expressing Isl1 are asymmetrically distributed in the developing normal heart. We now show that this population is reduced in the hearts from the Shh null mutants, likely contributing to the defects. To distinguish the consequences of reduced contributions from the second heart field from those of left-right patterning disturbance, we disrupted the movement of second heart field cells into the heart by expressing dominant-negative Rho kinase in the population of cells expressing Isl1. This resulted in absence of the vestibular spine, and presence of atrioventricular septal defects closely resembling those seen in the hearts from the Shh null mutants. The primary atrial septum, however, was well formed, and there was no evidence of isomerism of the atrial appendages, suggesting that these features do not relate to disruption of the contributions made by the second heart field. We demonstrate, therefore, that the Shh null mouse is a model of isomerism of the left atrial appendages, and show that the recognized associated malformations found at the venous pole of the heart in the setting of left isomerism are likely to arise from

  13. Flavonoid variation in Eurasian Sedum and Sempervivum

    NARCIS (Netherlands)

    Stevens, J.F; 't Hart, H; Elema, E.T; Bolck, A

    Flavonoids from vegetative parts of 29 species of Eurasian Sedum, Sedum meyeri-johannis from central East Africa, 34 species of Sempervivum, and Jovibarba heuffelii have been identified after acid hydrolysis. Ten flavonoid aglycones were detected, i.e. kaempferol, herbacetin, sexangularetin,

  14. Antimicrobial action of purified raspberry flavonoid

    African Journals Online (AJOL)

    user

    2012-02-07

    Feb 7, 2012 ... numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. *Corresponding author. E-mail: bdsunjinxu@163.com. (Cushnie et al., 2005), but there have been no reports on the bacteriostatic and bactericidal action of raspberry flavonoid. In this paper ...

  15. Antioxidant activity and total phenolic and flavonoid content of ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... Key words: Astragalus squarrosus, antioxidant, phenolics, flavonoids. INTRODUCTION ... Phenolic and flavonoid compounds are widely distri- buted plant constituents. ..... Antioxidant effects of some ginger constituents.

  16. Isomeric rations study for the α + 70 Ge

    International Nuclear Information System (INIS)

    Hora Villano, M.H. da.

    1984-12-01

    Isomeric ratios for 73 Se F,I produced in the reaction α + 70 Ge with incidence laboratory energy ranging from 8 to 28 MeV, have been measured using off-line γ-ray spectroscopy. Relative formation cross-section for isomeric and ground states were obtained with NAT Ge targets. Compound nucleus statistical analyses were performed using computer codes Alice and Julian. Unlike to Alice code, the Julian code predictions agreed quite well with the experimental results. This agreement may be explained by the inclusion of the γ competition in the deexcitation channels of the compound nucleus and by the correct level density calculation of the emission probabilities in the Julian code. Finally angular momentum populations for isomers formations in the reaction 70 Ge(α, n) 73 have been determined. (author)

  17. Determination of the production rate of low intensity isomeric transitions

    International Nuclear Information System (INIS)

    Lakosi, L.; Veres, A.; Tam, N.C.; Pavlicsek, I.

    1992-01-01

    Flat 2π and cylindrical 4π multiwire proportional counters were built for counting for low energy internal conversion electrons from the nuclear isomers 83m Kr, 103m Rh and 189m Os, induced by irradiation with high intensity 60 Co and 4 MeV bremsstrahlung sources. The β-decay of 176m Lu was recorded by a plastic scintillator. In this way higher sensitivities were attained than by detecting γ-rays or characteristic X-rays associated with the isomeric transitions, and the excitation of 189m Os by low energy 137 Cs and 300 kV X-ray sources also became detectable. Comparatively large isomeric activities produced by linac irradiation were standardizing by a Ge spectrometer for calibrating proportional and scintillation counting. (orig.)

  18. Study of the isomeric states of 66As

    International Nuclear Information System (INIS)

    Czajkowski, S.; Blank, B.; Andriamonje, S.; Attallah, F.; Boue, F.; Davi, F.; Del Moral, R.; Fleury, A.; Musquere, A.; Pravikoff, M.S.; Dufour, J-P; Grzywacz, R.; Janas, Z.; Karny, M.; Pfuetzner, M.; Donzaud, C.; Grewe, A.; Heinz, A.; Junghans, A.; Lewitowicz, M.; Sauvestre, J-E.

    1997-01-01

    The most neutron-deficient isotopes in the N = Z region are an important source of information on the neutron-proton interaction far off stability. The isotopes in this region are characterized by an extreme sensitivity of the deformation to the isospin variations. Here the structure of deformed shells are favoring the high spin states the lifetime of which being sufficient long to be observed after flight time of the order of the microsecond. The study of the decay of this isomeric states permits to approach the structure of the first excited levels of this isotopes. Recent experiments at GANIL with the SISSI - LISE 3 spectrometer were performed to study the neutron deficient nucleus 66 As. This nucleus was produced in the fragmentation of 70 MeV/u 78 Kr primary beam in a nickel target. Two new isomeric states have been observed. From the observed γ transitions a decay scheme is proposed

  19. Flavonoids as fruit and vegetable intake biomarkers

    DEFF Research Database (Denmark)

    Krogholm, Kirstine Suszkiewicz

    of fruit and vegetable intakes. In Paper I, the urinary recovery of the 7 flavonoids in morning spot urine (i.e. all urine voids from midnight including the first morning void) was also found to respond to moderate increases in the intake of fruits and vegetables. However, the association was somewhat...... weaker than in 24h urine samples, indicating that the 24h urinary recovery of the 7 flavonoids is a stronger biomarker of the intake of fruit and vegetables than the urinary recovery of the 7 flavonoids in morning spot urine. In Paper II, the biokinetic profiles of some of the most important dietary......-individual variation in the absorption and urinary recovery of the flavonoids, and this makes it very difficult to separate individuals according to intake by use of the flavonoid biomarker in urine. The intra-individual variation was on the contrary low, and Paper II therefore supports the assumption, that 24h...

  20. Marine natural flavonoids: chemistry and biological activities.

    Science.gov (United States)

    Martins, Beatriz T; Correia da Silva, Marta; Pinto, Madalena; Cidade, Honorina; Kijjoa, Anake

    2018-05-04

    As more than 70% of the world's surface is covered by oceans, marine organisms offer a rich and unlimited resource of structurally diverse bioactive compounds. These organisms have developed unique properties and bioactive compounds that are, in majority of them, unparalleled by their terrestrial counterparts due to the different surrounding ecological systems. Marine flavonoids have been extensively studied in the last decades due to a growing interest concerning their promising biological/pharmacological activities. The most common classes of marine flavonoids are flavones and flavonols, which are mostly isolated from marine plants. Although most of flavonoids are hydroxylated and methoxylated, some marine flavonoids possess an unusual substitution pattern, not commonly found in terrestrial organisms, namely the presence of sulphate, chlorine, and amino groups. This review presents, for the first time in a systematic way, the structure, natural occurrence, and biological activities of marine flavonoids.

  1. Surface study of mixtures containing cyclic ethers and isomeric chlorobutanes

    International Nuclear Information System (INIS)

    Royo, F.M.; Villares, A.; Martin, S.; Giner, B.; Lafuente, C.

    2007-01-01

    Experimental surface tensions and the corresponding surface tensions deviations for the mixtures containing 1,3-dioxolane or 1,4-dioxane and 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane or 2-chloro-2-methylpropane, measured with a drop volume tensiometer, are reported at the temperatures of 298.15 K and 313.15 K. The excess surface concentrations of isomeric chlorobutanes are also evaluated using a monolayer model

  2. Deconstructing field-induced ketene isomerization through Lagrangian descriptors.

    Science.gov (United States)

    Craven, Galen T; Hernandez, Rigoberto

    2016-02-07

    The time-dependent geometrical separatrices governing state transitions in field-induced ketene isomerization are constructed using the method of Lagrangian descriptors. We obtain the stable and unstable manifolds of time-varying transition states as dynamic phase space objects governing configurational changes when the ketene molecule is subjected to an oscillating electric field. The dynamics of the isomerization reaction are modeled through classical trajectory studies on the Gezelter-Miller potential energy surface and an approximate dipole moment model which is coupled to a time-dependent electric field. We obtain a representation of the reaction geometry, over varying field strengths and oscillation frequencies, by partitioning an initial phase space into basins labeled according to which product state is reached at a given time. The borders between these basins are in agreement with those obtained using Lagrangian descriptors, even in regimes exhibiting chaotic dynamics. Major outcomes of this work are: validation and extension of a transition state theory framework built from Lagrangian descriptors, elaboration of the applicability for this theory to periodically- and aperiodically-driven molecular systems, and prediction of regimes in which isomerization of ketene and its derivatives may be controlled using an external field.

  3. Flavonoids in Kidney Health and Disease

    Directory of Open Access Journals (Sweden)

    Félix Vargas

    2018-04-01

    Full Text Available This review summarizes the latest advances in knowledge on the effects of flavonoids on renal function in health and disease. Flavonoids have antihypertensive, antidiabetic, and antiinflammatory effects, among other therapeutic activities. Many of them also exert renoprotective actions that may be of interest in diseases such as glomerulonephritis, diabetic nephropathy, and chemically-induced kidney insufficiency. They affect several renal factors that promote diuresis and natriuresis, which may contribute to their well-known antihypertensive effect. Flavonoids prevent or attenuate the renal injury associated with arterial hypertension, both by decreasing blood pressure and by acting directly on the renal parenchyma. These outcomes derive from their interference with multiple signaling pathways known to produce renal injury and are independent of their blood pressure-lowering effects. Oral administration of flavonoids prevents or ameliorates adverse effects on the kidney of elevated fructose consumption, high fat diet, and types I and 2 diabetes. These compounds attenuate the hyperglycemia-disrupted renal endothelial barrier function, urinary microalbumin excretion, and glomerular hyperfiltration that results from a reduction of podocyte injury, a determinant factor for albuminuria in diabetic nephropathy. Several flavonoids have shown renal protective effects against many nephrotoxic agents that frequently cause acute kidney injury (AKI or chronic kidney disease (CKD, such as LPS, gentamycin, alcohol, nicotine, lead or cadmium. Flavonoids also improve cisplatin- or methotrexate-induced renal damage, demonstrating important actions in chemotherapy, anticancer and renoprotective effects. A beneficial prophylactic effect of flavonoids has been also observed against AKI induced by surgical procedures such as ischemia/reperfusion (I/R or cardiopulmonary bypass. In several murine models of CKD, impaired kidney function was significantly improved by

  4. Identification and quantification of caffeoylquinic acids and flavonoids from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC-DAD-ESI/MS(n).

    Science.gov (United States)

    Schütz, Katrin; Kammerer, Dietmar; Carle, Reinhold; Schieber, Andreas

    2004-06-30

    A method for the identification and quantification of phenolic compounds from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC with diode array and mass spectrometric detection was developed. Among the 22 major compounds, 11 caffeoylquinic acids and 8 flavonoids were detected. Quantification of individual compounds was carried out by external calibration. Apigenin 7-O-glucuronide was found to be the major flavonoid in all samples investigated. 1,5-Di-O-caffeoylquinic acid represented the major hydroxycinnamic acid, with 3890 mg/kg in artichoke heads and 3269 mg/kg in the pomace, whereas in the juice 1,3-di-O-caffeoylquinic acid (cynarin) was predominant, due to the isomerization during processing. Total phenolic contents of approximately 12 g/kg on a dry matter basis revealed that artichoke pomace is a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.

  5. Tracer kinetic investigations on isomerization and synthesis of /sup 8/C-aromates. II. Isomerization of ethylbenzene by means of heterogeneous catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Dermietzel, J; Roesseler, M; Jockisch, W; Wienhold, C [Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung; Franke, H; Klempin, J; Barz, H J [VEB Petrolchemisches Kombinat Schwedt (German Democratic Republic)

    1978-01-01

    The mechanism of ethylbenzene isomerization on Pt/Al/sub 2/O/sub 3/ catalysts by means of /sup 14/C labelled compounds has been investigated, measuring the isotope distribution between ring and alkyl carbon atoms. The results suggest that ethylbenzene isomerizes via structure rearrangement involving ring carbon atoms. A similar mechanism takes place in xylene isomerization under increased hydrogen partial pressure, while under normal pressure 1,2-methyl group shifting is dominating. All three xylenes are formed from ethylbenzene by parallel reactions.

  6. Differential accumulation of flavonoids by tomato (Solanum ...

    African Journals Online (AJOL)

    SARAH

    2014-12-29

    Dec 29, 2014 ... Objective: Little is known about physiological functions of flavonoids, specifically in the course of maturation ... epicarp (especially naringenin) with the onset of the ripening. ..... the University of Chemical Technology and.

  7. Structure-cytotoxicity relationships for dietary flavonoids

    DEFF Research Database (Denmark)

    Breinholt, V.; Dragsted, L.O.

    1998-01-01

    The cytotoxicity of a large series of dietary flavonoids was tested in a non-tumorigenic mouse and two human cancer cell lines, using the neutral red dye exclusion assay. All compounds tested exhibited a concentration-dependent cytotoxic action in the employed cell lines. The relative cytotoxicity...... of the flavonoids, however, Tvas found to vary greatly among the different cell Lines. With a few exceptions, the investigated flavonoids were more cytotoxic to the human cancer cell lines, than the mouse cell line. The differences in cytotoxicity were accounted for in part by differences in cellular uptake...... and metabolic capacity among the different cell types. In 3T3 cells fairly consistent structure-cytotoxicity relationships were found. The most cytotoxic structures tested in 3T3 cells were flavonoids with adjacent 3',4' hydroxy groups on the B-ring, such as luteolin, quercetin, myricetin, fisetin, eriodictyol...

  8. Flavonoids as fruit and vegetable intake biomarkers

    DEFF Research Database (Denmark)

    Krogholm, Kirstine Suszkiewicz

    calculation of the bivariate correlation coefficients is the common approach when using only one reference method. Back in 2002, a strictly controlled dietary intervention study indicated that the sum of 7 different flavonoid aglycones excreted in 24h urine samples potentially could be used as a biomarker...... and cohort studies. The Ph.D. thesis contains four scientific papers. Paper I provides evidence that the sum of 7 flavonoids in 24h urine respond in a linear and sensitive manner to moderate increases in the intake of fruits and vegetables, and thus consolidates that the flavonoids are a valid biomarker...... of fruit and vegetable intakes. In Paper I, the urinary recovery of the 7 flavonoids in morning spot urine (i.e. all urine voids from midnight including the first morning void) was also found to respond to moderate increases in the intake of fruits and vegetables. However, the association was somewhat...

  9. 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 (

  10. Combined Function of Brønsted and Lewis Acidity in the Zeolite-Catalyzed Isomerization of Glucose to Fructose in Alcohols

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Riisager, Anders; Taarning, Esben

    2016-01-01

    Glucose conversion via fructose to useful chemicals and fuels has attracted considerable attention. Isomerization of glucose to fructose can proceed along several different reaction pathways involving different sugar intermediates and isomeric forms. Presently, the roles of the substrate isomeric...

  11. Wine Flavonoids in Health and Disease Prevention

    Directory of Open Access Journals (Sweden)

    Iva Fernandes

    2017-02-01

    Full Text Available Wine, and particularly red wine, is a beverage with a great chemical complexity that is in continuous evolution. Chemically, wine is a hydroalcoholic solution (~78% water that comprises a wide variety of chemical components, including aldehydes, esters, ketones, lipids, minerals, organic acids, phenolics, soluble proteins, sugars and vitamins. Flavonoids constitute a major group of polyphenolic compounds which are directly associated with the organoleptic and health-promoting properties of red wine. However, due to the insufficient epidemiological and in vivo evidences on this subject, the presence of a high number of variables such as human age, metabolism, the presence of alcohol, the complex wine chemistry, and the wide array of in vivo biological effects of these compounds suggest that only cautious conclusions may be drawn from studies focusing on the direct effect of wine and any specific health issue. Nevertheless, there are several reports on the health protective properties of wine phenolics for several diseases such as cardiovascular diseases, some cancers, obesity, neurodegenerative diseases, diabetes, allergies and osteoporosis. The different interactions that wine flavonoids may have with key biological targets are crucial for some of these health-promoting effects. The interaction between some wine flavonoids and some specific enzymes are one example. The way wine flavonoids may be absorbed and metabolized could interfere with their bioavailability and therefore in their health-promoting effect. Hence, some reports have focused on flavonoids absorption, metabolism, microbiota effect and overall on flavonoids bioavailability. This review summarizes some of these major issues which are directly related to the potential health-promoting effects of wine flavonoids. Reports related to flavonoids and health highlight some relevant scientific information. However, there is still a gap between the knowledge of wine flavonoids

  12. Foliar flavonoids of nine species of Bauhinia

    OpenAIRE

    SALATINO, ANTONIO; BLATT, CECÍLIA T.T.; SANTOS, DÉBORAH Y.A.C. DOS; VAZ, ANGELA M.S.F.

    1999-01-01

    Foliar flavonoids of nine species of Bauhinia were isolated and identified. All the compounds correspond to glycosides derived from kaempferol, quercetin, isorhamnetin and myricetin. Derivatives of the latter aglyconhe seem to be rare in Bauhinia. Derivatives of isorhamnetin are commonly found in species of subgenus Bauhinia and were not detected in the two species of subgenus Phanera. Flavonoid patterns of species of the former subgenus are in general more complex than those of the latter. ...

  13. Antioxidant flavonoids bind human serum albumin

    Science.gov (United States)

    Kanakis, C. D.; Tarantilis, P. A.; Polissiou, M. G.; Diamantoglou, S.; Tajmir-Riahi, H. A.

    2006-10-01

    Human serum albumin (HSA) is a principal extracellular protein with a high concentration in blood plasma and carrier for many drugs to different molecular targets. Flavonoids are powerful antioxidants and prevent DNA damage. The antioxidative protections are related to their binding modes to DNA duplex and complexation with free radicals in vivo. However, flavonoids are known to inhibit the activities of several enzymes such as calcium phospholipid-dependent protein kinase, tyrosine protein kinase from rat lung, phosphorylase kinase, phosphatidylinositol 3-kinase and DNA topoisomerases that exhibit the importance of flavonoid-protein interaction. This study was designed to examine the interaction of human serum albumin (HSA) with quercetin (que), kaempferol (kae) and delphinidin (del) in aqueous solution at physiological conditions, using constant protein concentration of 0.25 mM (final) and various drug contents of 1 μM-1 mM. FTIR and UV-vis spectroscopic methods were used to determine the polyphenolic binding mode, the binding constant and the effects of flavonoid complexation on protein secondary structure. The spectroscopic results showed that flavonoids are located along the polypeptide chains through H-bonding interactions with overall affinity constant of Kque = 1.4 × 10 4 M -1, Kkae = 2.6 × 10 5 M -1 and Kdel = 4.71 × 10 5 M -1. The protein secondary structure showed no alterations at low pigment concentration (1 μM), whereas at high flavonoid content (1 mM), major reduction of α-helix from 55% (free HSA) to 42-46% and increase of β-sheet from 15% (free HSA) to 17-19% and β-anti from 7% (free HSA) to 10-20% occurred in the flavonoid-HSA adducts. The major reduction of HSA α-helix is indicative of a partial protein unfolding upon flavonoid interaction.

  14. Pion condensation and density isomerism in nuclear matter

    International Nuclear Information System (INIS)

    Hecking, P.; Weise, W.

    1979-01-01

    The possible existence of density isomers in nuclear matter, induced by pion condensation, is discussed; the nuclear equation of state is treated within the framework of the sigma model. Repulsive short-range baryon-baryon correlations, the admixture of Δ (1232) isobars and finite-range pion-baryon vertex form factors are taken into account. The strong dependence of density isomerism on the high density extrapolation of the equation of state for normal nuclear matter is also investigated. We find that, once finite range pion-baryon vertices are introduced, the appearance of density isomers becomes unlikely

  15. Synthesis of heterocycles through transition-metal-catalyzed isomerization reactions

    DEFF Research Database (Denmark)

    Ishøy, Mette; Nielsen, Thomas Eiland

    2014-01-01

    of structurally complex and diverse heterocycles. In this Concept article, we attempt to cover this area of research through a selection of recent versatile examples. A sea of opportunities! Transition-metal-catalyzed isomerization of N- and O-allylic compounds provides a mild, selective and synthetically...... versatile method to form iminium and oxocarbenium ions. Given the number of reactions involving these highly electrophilic intermediates, this concept provides a sea of opportunities for heterocycle synthesis, (see scheme; Nu=nucleophile). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  16. Geometrical Optimization Approach to Isomerization: Models and Limitations.

    Science.gov (United States)

    Chang, Bo Y; Shin, Seokmin; Engel, Volker; Sola, Ignacio R

    2017-11-02

    We study laser-driven isomerization reactions through an excited electronic state using the recently developed Geometrical Optimization procedure. Our goal is to analyze whether an initial wave packet in the ground state, with optimized amplitudes and phases, can be used to enhance the yield of the reaction at faster rates, driven by a single picosecond pulse or a pair of femtosecond pulses resonant with the electronic transition. We show that the symmetry of the system imposes limitations in the optimization procedure, such that the method rediscovers the pump-dump mechanism.

  17. Isomeric island in the vicinity of 66Fe

    International Nuclear Information System (INIS)

    Daugas, J. M.; Belier, G.; Girod, M.; Goutte, H.; Meot, V.; Perru, O.; Roig, O.; Sauvestre, J. E.; Sawicka, M.; Pfuetzner, M.; Zylicz, J.; Matea, I.; Giovinazzo, J.; Grawe, H.; Becker, F.; Mayet, P.; Grzywacz, R.; Achouri, N. L.; Angelique, J. C.; Baiborodin, D.

    2006-01-01

    An island of isomers have recently been observed on both sides of the N=40 shell below the Ni isotopes. Isomeric states in the 65Fe and 67Fe allow the knowledge of the single particle structure around the νg9/2 shell. Moreover, the excitation energy of the first 2+ and 4+ states in the 68Fe have been established by β-γ correlation. The evolution of the structure of the Fe isotopes going far away from the valley of stability is, for the first time, given for N>40

  18. Xylose Isomerization with Zeolites in a Two-Step Alcohol–Water Process

    DEFF Research Database (Denmark)

    Paniagua, Marta; Shunmugavel, Saravanamurugan; Melián Rodriguez, Mayra

    2015-01-01

    Isomerization of xylose to xylulose was efficiently catalyzed by large-pore zeolites in a two-step methanol–water process that enhanced the product yield significantly. The reaction pathway involves xylose isomerization to xylulose, which, in part, subsequently reacts with methanol to form methyl...

  19. Control of structural isomerism in noncovalent hydrogen-bonded assemblies using peripheral chiral information

    NARCIS (Netherlands)

    Prins, L.J.; Jolliffe, K.A.; Hulst, A.J.R.L.; Timmerman, P.; Reinhoudt, David

    2000-01-01

    The results of a systematic study of the structural isomerism in more than 30 noncovalent hydrogen-bonded assemblies are described. These dynamic assemblies, composed of three calix[4]arene dimelamines and six barbiturates/cyanurates, can be present in three isomeric forms with either D3, C3h, or Cs

  20. Iridium-Catalyzed Dynamic Kinetic Isomerization: Expedient Synthesis of Carbohydrates from Achmatowicz Rearrangement Products.

    Science.gov (United States)

    Wang, Hao-Yuan; Yang, Ka; Bennett, Scott R; Guo, Sheng-rong; Tang, Weiping

    2015-07-20

    A highly stereoselective dynamic kinetic isomerization of Achmatowicz rearrangement products was discovered. This new internal redox isomerization provided ready access to key intermediates for the enantio- and diastereoselective synthesis of a series of naturally occurring sugars. The nature of the de novo synthesis also enables the preparation of both enantiomers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Analysis of Optimal Process Flow Diagrams of Light Naphtha Isomerization Process by Mathematic Modelling Method

    OpenAIRE

    Chuzlov, Vyacheslav Alekseevich; Molotov, Konstantin

    2016-01-01

    An approach to simulation of hydrocarbons refining processes catalytic reactors. The kinetic and thermodynamic research of light naphtha isomerization process was conducted. The kinetic parameters of hydrocarbon feedstock chemical conversion on different types of platinum-content catalysts was established. The estimation of efficiency of including different types of isomerization technologies in oil refinery flow diagram was performed.

  2. Green Synthesis of Carvenone by Montmorillonite-Catalyzed Isomerization of 1,2-Limonene Oxide

    DEFF Research Database (Denmark)

    Nguyen, Thao-Tran Thi; Chau, Duy-Khiem Nguyen; Duus, Fritz

    2013-01-01

    Montmorillonite was considered as a good heterogeneous catalyst for the isomerization of 1,2-limonene oxide into car-venone under solvent-free condition. Both conventional heating and green activations were tested in this research. The microwave-assisted isomerization afforded carvenone in high...

  3. Analysis of Optimal Process Flow Diagrams of Light Naphtha Isomerization Process by Mathematic Modelling Method

    Directory of Open Access Journals (Sweden)

    Chuzlov Vjacheslav

    2016-01-01

    Full Text Available An approach to simulation of hydrocarbons refining processes catalytic reactors. The kinetic and thermodynamic research of light naphtha isomerization process was conducted. The kinetic parameters of hydrocarbon feedstock chemical conversion on different types of platinum-content catalysts was established. The estimation of efficiency of including different types of isomerization technologies in oil refinery flow diagram was performed.

  4. Tandem ring-closing metathesis/isomerization reactions for the total synthesis of violacein

    DEFF Research Database (Denmark)

    Petersen, Mette Terp; Nielsen, Thomas Eiland

    2013-01-01

    A series of 5-substituted 2-pyrrolidinones was synthesized through a one-pot ruthenium alkylidene-catalyzed tandem RCM/isomerization/nucleophilic addition sequence. The intermediates resulting from RCM/isomerization showed reactivity toward electrophiles in aldol condensation reactions which...

  5. Excitation functions and isomeric ratios for the isomeric pair sup(106m)Ag and sup(106g)Ag in the 107Ag (d,t) reaction

    International Nuclear Information System (INIS)

    Lalli, M.E.; Wasilevsky de Lammirato, C.; Herreros, O.R.; Nassiff, S.J.

    1976-09-01

    Excitation functions and isomeric cross section ratios have been measured for the 107 Ag (d,t), reaction in which the isomeric pair sup(106m/106g)Ag is produced. Thick-target yields have been determined for different irradiation times and as a function of deuteron energy. Stacked silver foils with aluminium foils as monitors were bombarded with deuterons up to 27 MeV and the activities of products measured with a calibrated Ge(Li) counter. (author) [es

  6. Process for paraffin isomerization of a distillate range hydrocarbon feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N.Y.; Garwood, W.E.; McCullen, S.B.

    1993-01-19

    Various catalytic processes have been proposed to isomerize n-paraffins so as to lower the pour point of distillate range hydrocarbon feedstocks. However, many available feedstocks contain nitrogen impurities which tend to poison conventional paraffin isomerization catalysts. A process has been developed to obviate or alleviate this problem. According to the invention, the paraffin-containing feedstock is contacted with a crystalline aluminosilicate zeolite catalyst having pore openings defined by a ratio of sorption of n-hexane to o-xylene of over 3 vol % and the ability to crack 3-methylpentane in preference to 2,3 dimethylbutane under defined conditions. The zeolite catalyst includes a Group VIII metal and has a zeolite SiO[sub 2]/Al[sub 2]O[sub 3] ratio of at least 20:1. The contacting is carried out at 199-454 C and a pressure of 100-1,000 psig, preferably 250-600 psig. The group of medium pore zeolites which can be used in the process of the invention includes ZSM-22, ZSM-23, and ZSM-35. The Group VIII metals used in the catalyst are preferably selected from Pt, Pd, Ir, Os, Rh, and Ru and the metal is preferably incorporated into the zeolite by ion exchange up to a metal content of preferably 0.1-3 wt %. Experiments are described to illustrate the invention. 1 tab.

  7. Computational Studies of Bridging Structures and Isomerism in Substituted Disilynes.

    Science.gov (United States)

    Serafin, Lukasz M; Law, Mark M; van Mourik, Tanja

    2013-06-11

    The substituted disilyne molecules, Si2Li2 and Si2HX, where X = Li, F, and Cl, have been investigated using the high-level CCSD(T) and CCSD(T)-F12 ab initio methods. The calculations have found or confirmed the existence of several isomeric forms and transition states for each molecule. Optimized geometries, relative energies, and harmonic vibration frequencies are reported. Bridging structures exist in all cases. Comparisons are made with existing literature results for the related Si2H2, C2X2, and C2HX isomerizing systems. Additionally, CCSD(T) and CCSD(T)-F12 calculations were performed for Si2H2, for which experimental spectroscopic data are available. Results calculated with CCSD(T)-F12 and the cc-pVTZ-F12 basis set are of comparable quality as those computed with CCSD(T) and the much larger cc-pV(6+d)Z basis set, at much less computational cost. We recommend the CCSD(T)-F12/cc-pVTZ-F12 level of theory as a very attractive alternative to conventional CCSD(T).

  8. Low-lying isomeric levels in Cu75

    Science.gov (United States)

    Daugas, J. M.; Faul, T.; Grawe, H.; Pfützner, M.; Grzywacz, R.; Lewitowicz, M.; Achouri, N. L.; Angélique, J. C.; Baiborodin, D.; Bentida, R.; Béraud, R.; Borcea, C.; Bingham, C. R.; Catford, W. N.; Emsallem, A.; de France, G.; Grzywacz, K. L.; Lemmon, R. C.; Lopez Jimenez, M. J.; de Oliveira Santos, F.; Regan, P. H.; Rykaczewski, K.; Sauvestre, J. E.; Sawicka, M.; Stanoiu, M.; Sieja, K.; Nowacki, F.

    2010-03-01

    Isomeric low-lying states were identified and investigated in the Cu75 nucleus. Two states at 61.8(5)- and 128.3(7)-keV excitation energies with half-lives of 370(40)- and 170(15)-ns were assigned as Cu75m1 and Cu75m2, respectively. The measured half-lives combined with the recent spin assignment of the ground state allow one to deduce tentatively spin and parity of the two isomers and the dominant multipolarities of the isomeric transitions with respect to the systematics of the Cu isotopes. Shell-model calculations using an up-to-date effective interaction reproduce the evolution of the 1/2-, 3/2-, and 5/2- states for the neutron-rich odd-mass Cu isotopes when filling the νg9/2. The results indicate a significant change in the nuclear structure in this region, where a single-particle 5/2- state coexists with more and more collective 3/2- and 1/2- levels at low excitation energies.

  9. Destabilization in the isomeric nitrobenzonitriles: an experimental thermochemical study

    International Nuclear Information System (INIS)

    Roux, Maria Victoria; Jimenez, Pilar; Davalos, Juan Z.; Temprado, Manuel; Liebman, Joel F.

    2003-01-01

    The enthalpies of combustion and of sublimation, respectively, of the three isomeric nitrobenzonitriles have been measured: o-, {(-3456.3±2.9), (88.1±1.4)} kJ·mol -1 ; m-, {(-3442.8±3.3), (92.8±0.3)} kJ·mol -1 ; p-, {(-3448.2±3.6), (91.1±1.3)} kJ·mol -1 . In turn, from these values, the standard molar enthalpies of formation for the condensed and gaseous state, respectively, have been derived: o-, {(130.1±3.1), (218.2±3.4)} kJ·mol -1 ; m-, {(116.5±3.5), (209.3±3.5)} kJ·mol -1 ; p-, {(122.0±3.8), (213.1±4.0)} kJ·mol -1 . Destabilization energies associated with the presence of the two electron-withdrawing groups have been determined, for o-, m-, and p-nitrobenzonitrile, {(17.6±4.1), (8.7±4.2), and (12.5±4.6)} kJ·mol -1 , respectively, and are consistent with those obtained for the corresponding sets of isomeric methyl benzenedicarboxylates, dicyanobenzenes, dinitrobenzenes, and (neutral and ionized) nitrobenzoic acids

  10. Catalyst compositions useful for olefin isomerization and disproportionation

    International Nuclear Information System (INIS)

    Drake, C.A.

    1987-01-01

    A process is described for the double bond isomerization of an aliphatic olefinic hydrocarbon feed which comprises contacting the feed under isomerization conditions with a catalyst prepared by: (a) impregnating an alumina support having a surface area of at least 200 m/sup 2//g and a pore volume of at least 0.45 cm/sup 3//g with: 1 up to 20 wt. % of at least one magnesium compound convertible to the oxide, based on the weight of support and calculated as the metal; 0 up to 5 wt. % of at least one alkali metal compound convertible to the oxide, based on the weight of support and calculated as the metal; and 0 up to 5 wt. % of at least one zirconium compound convertible to the oxide, based on the weight of support and calculated as the metal; and (b) heating the alumina support impregnated in accordance with step (a) in an oxygen-containing atmosphere under conditions suitable to convert at least a portion of the magnesium, alkali metal, and zirconium compounds to the oxide form

  11. Flavonoids, Flavonoid Subclasses, and Esophageal Cancer Risk: A Meta-Analysis of Epidemiologic Studies.

    Science.gov (United States)

    Cui, Lingling; Liu, Xinxin; Tian, Yalan; Xie, Chen; Li, Qianwen; Cui, Han; Sun, Changqing

    2016-06-08

    Flavonoids have been suggested to play a chemopreventive role in carcinogenesis. However, the epidemiologic studies assessing dietary intake of flavonoids and esophageal cancer risk have yielded inconsistent results. This study was designed to examine the association between flavonoids, each flavonoid subclass, and the risk of esophageal cancer with a meta-analysis approach. We searched for all relevant studies with a prospective cohort or case-control study design published from January 1990 to April 2016, using PUBMED, EMBASE, and Web of Science. Pooled odds ratios (ORs) were calculated using fixed or random-effect models. In total, seven articles including 2629 cases and 481,193 non-cases were selected for the meta-analysis. Comparing the highest-intake patients with the lowest-intake patients for total flavonoids and for each flavonoid subclass, we found that anthocyanidins (OR = 0.60, 95% CI: 0.49-0.74), flavanones (OR = 0.65, 95% CI: 0.49-0.86), and flavones (OR = 0.78, 95% CI 0.64-0.95) were inversely associated with the risk of esophageal cancer. However, total flavonoids showed marginal association with esophageal cancer risk (OR = 0.78, 95% CI: 0.59-1.04). In conclusion, our study suggested that dietary intake of total flavonoids, anthocyanidins, flavanones, and flavones might reduce the risk of esophageal cancer.

  12. [Advance in flavonoids biosynthetic pathway and synthetic biology].

    Science.gov (United States)

    Zou, Li-Qiu; Wang, Cai-Xia; Kuang, Xue-Jun; Li, Ying; Sun, Chao

    2016-11-01

    Flavonoids are the valuable components in medicinal plants, which possess a variety of pharmacological activities, including anti-tumor, antioxidant and anti-inflammatory activities. There is an unambiguous understanding about flavonoids biosynthetic pathway, that is,2S-flavanones including naringenin and pinocembrin are the skeleton of other flavonoids and they can transform to other flavonoids through branched metabolic pathway. Elucidation of the flavonoids biosynthetic pathway lays a solid foundation for their synthetic biology. A few flavonoids have been produced in Escherichia coli or yeast with synthetic biological technologies, such as naringenin, pinocembrin and fisetin. Synthetic biology will provide a new way to get valuable flavonoids and promote the research and development of flavonoid drugs and health products, making flavonoids play more important roles in human diet and health. Copyright© by the Chinese Pharmaceutical Association.

  13. The Role of Flavonoids as Potential Radioprotectors

    International Nuclear Information System (INIS)

    Benkovic, V.; Djikic, D.; Horvat Knezevic, A.; Lisicic, D.; Orsolic, N.; Kopjar, N.

    2011-01-01

    Investigations for effective and non toxic compounds with radioprotection capability led to increasing interest in naturally occurring antioxidants since most of known chemical radioprotectors (AET, WR2721, WR 1065, etc.) express toxic side effects that limit their use in medical practice. Among the promissing compounds there are flavonoids, whosentioxidant activity is based on ability of direct free radicals scavenging or stabilizing the reactive oxygen species (ROS) by interacting with the reactive compound of the radical. Because of the high reactivity of the hydroxyl substituents of flavonoids, radicals are made inactive. Flavonoids can also increase the function of the endogenous antioxidant enzyme systems: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and gluthation. Antioxidant effects may be also a combined result of radical scavenging and interaction with enzyme functions. Flavonoids induce activities of the immune system as well. Increased hematopoietic activity could account for the improved hematopoietic tolerance to radiotherapy. In this study we evaluated radioprotective effects of selected flavonoids (caffeic acid, chrysin, naringin and quercetin) administered to mice prior to whole-body irradiation with γ-rays (absorbed dose was 9 Gy). The survival analysis and alkaline comet assay on white blood cells were employed both on irradiated and non-irradiated animals. Blood samples were taken 30 min. after irradiation. Appropriate negative and positive control groups (administered chemical radioprotector AET, S-(2-Aminoethyl) isothiouronium bromide hydrobromide, i. p. at a dose of 281 mg kg -1 body weight) were also selected and handled in the same manner. We observed statistically significant difference in surviving time of mice pre-treated with test components and the most effective radioprotector was quercetin. Tested flavonoids were not genotoxic to non-irradiated mice and offered good

  14. Flavonoids from leaves of Mauritia flexuosa

    Directory of Open Access Journals (Sweden)

    Djalma M. de Oliveira

    2013-09-01

    Full Text Available The chromatographic fractionation of the Mauritia flexuosa L. f., Arecaceae, leaves extract, a plant known by the name of buriti palm tree, resulted in the isolation of six flavonoids: tricin-7-O-rutinoside, apigenin-6-C-arabinoside, 8-C-glucoside (isoschaftoside, kaempferol-3-O-rutinoside (nicotiflorine, quercetin-3-O-rutinoside (rutin, luteolin-8-C-glucoside (orientin and luteolin-6-C-glucoside (isoorientin. The flavonoids were found out and previously reported as constituents of the Arecaceae family plants, but the occurrence of C-glucoside flavonoids, in the species being analyzed, is described for the first time on this study. The structural elucidations of all of the isolated compounds were performed by means of the comparison of their spectral data (¹H and 13C NMR, UV and ESI-MS with those ones of the literature.

  15. Flavonoids in Inflammatory Bowel Disease: A Review

    Science.gov (United States)

    Vezza, Teresa; Rodríguez-Nogales, Alba; Algieri, Francesca; Utrilla, Maria Pilar; Rodriguez-Cabezas, Maria Elena; Galvez, Julio

    2016-01-01

    Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the intestine that compromises the patients’ life quality and requires sustained pharmacological and surgical treatments. Since their etiology is not completely understood, non-fully-efficient drugs have been developed and those that have shown effectiveness are not devoid of quite important adverse effects that impair their long-term use. In this regard, a growing body of evidence confirms the health benefits of flavonoids. Flavonoids are compounds with low molecular weight that are widely distributed throughout the vegetable kingdom, including in edible plants. They may be of great utility in conditions of acute or chronic intestinal inflammation through different mechanisms including protection against oxidative stress, and preservation of epithelial barrier function and immunomodulatory properties in the gut. In this review we have revised the main flavonoid classes that have been assessed in different experimental models of colitis as well as the proposed mechanisms that support their beneficial effects. PMID:27070642

  16. Flavonoids in Inflammatory Bowel Disease: A Review

    Directory of Open Access Journals (Sweden)

    Teresa Vezza

    2016-04-01

    Full Text Available Inflammatory bowel disease (IBD is characterized by chronic inflammation of the intestine that compromises the patients’ life quality and requires sustained pharmacological and surgical treatments. Since their etiology is not completely understood, non-fully-efficient drugs have been developed and those that have shown effectiveness are not devoid of quite important adverse effects that impair their long-term use. In this regard, a growing body of evidence confirms the health benefits of flavonoids. Flavonoids are compounds with low molecular weight that are widely distributed throughout the vegetable kingdom, including in edible plants. They may be of great utility in conditions of acute or chronic intestinal inflammation through different mechanisms including protection against oxidative stress, and preservation of epithelial barrier function and immunomodulatory properties in the gut. In this review we have revised the main flavonoid classes that have been assessed in different experimental models of colitis as well as the proposed mechanisms that support their beneficial effects.

  17. Association of flavonoid-rich foods and flavonoids with risk of all-cause mortality.

    Science.gov (United States)

    Ivey, Kerry L; Jensen, Majken K; Hodgson, Jonathan M; Eliassen, A Heather; Cassidy, Aedín; Rimm, Eric B

    2017-05-01

    Flavonoids are bioactive compounds found in foods such as tea, red wine, fruits and vegetables. Higher intakes of specific flavonoids, and flavonoid-rich foods, have been linked to reduced mortality from specific vascular diseases and cancers. However, the importance of flavonoid-rich foods, and flavonoids, in preventing all-cause mortality remains uncertain. As such, we examined the association of intake of flavonoid-rich foods and flavonoids with subsequent mortality among 93 145 young and middle-aged women in the Nurses' Health Study II. During 1 838 946 person-years of follow-up, 1808 participants died. When compared with non-consumers, frequent consumers of red wine, tea, peppers, blueberries and strawberries were at reduced risk of all-cause mortality (Pflavonoid intake were at reduced risk of all-cause mortality in the age-adjusted model; 0·81 (95 % CI 0·71, 0·93). However, this association was attenuated following multivariable adjustment; 0·92 (95 % CI 0·80, 1·06). Similar results were observed for consumption of flavan-3-ols, proanthocyanidins and anthocyanins. Flavonols, flavanones and flavones were not associated with all-cause mortality in any model. Despite null associations at the compound level and select foods, higher consumption of red wine, tea, peppers, blueberries and strawberries, was associated with reduced risk of total and cause-specific mortality. These findings support the rationale for making food-based dietary recommendations.

  18. β-γ and isomeric decay spectroscopy of 168Dy

    Directory of Open Access Journals (Sweden)

    Zhang G.X.

    2018-01-01

    Full Text Available This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

  19. β-γ and isomeric decay spectroscopy of 168Dy

    Science.gov (United States)

    Zhang, G. X.; Watanabe, H.; Kondev, F. G.; Lane, G. J.; Regan, P. H.; Söderström, P.-A.; Walker, P. M.; Kanaoka, H.; Korkulu, Z.; Lee, P. S.; Liu, J. J.; Nishimura, S.; Wu, J.; Yagi, A.; Ahn, D. S.; Alharbi, T.; Baba, H.; Browne, F.; Bruce, A. M.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Doornenbal, P.; Estrade, A.; Fukuda, N.; Griffin, C.; Ideguchi, E.; Inabe, N.; Isobe, T.; Kanaya, S.; Kojouharov, I.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lee, C. S.; Lee, E. J.; Lorusso, G.; Lotay, G.; Moon, C.-B.; Nishizuka, I.; Nita, C. R.; Odahara, A.; Patel, Z.; Phong, V. H.; Podolyák, Zs.; Roberts, O. J.; Sakurai, H.; Schaffner, H.; Shand, C. M.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Valiente-Dóbon, J. J.; Xu, Z. Y.

    2018-05-01

    This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

  20. Flavonoids – Small Molecules, High Hopes

    Directory of Open Access Journals (Sweden)

    Sandu Mariana

    2017-07-01

    Full Text Available This brief review takes a look at flavonoids, a wide class of polyphenols, which are regarded as plant secondary metabolites. Their roles in plants are diverse and little understood. They can act as growth hormone modulators, phytoalexins, they offer UV protection, contribute to pollen viability and can function as signaling molecules in establishing symbiotic relationships. Flavonoids were also found to have a range of beneficial effects for the human body. Their anticancer, antioxidant, anti-inflammatory and cardioprotective activity, as well as their antibacterial, antiviral and antihelmintic properties make them promising candidates for the design of new drugs.

  1. Flavonoids and terpenoids from Croton muscicarpa (Euphorbiaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Milena B.; Gomes, Clerton L.; Freitas, Joao Vito B. de; Pinto, Francisco das Chagas L.; Silveira, Edilberto R.; Gramosa, Nilce V., E-mail: nilce@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Centro de Ciencias, Universidade Federal do Ceara, Fortaleza (Brazil); Torres, Daniela S. Carneiro [Departamento de Ciencias Biologicas Jequie, Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil)

    2013-09-01

    A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Muell.. Arg.. Their structures were identified as the terpenoids 6{alpha}-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4'-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4'-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, {sup 1}H and {sup 13}C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY) and comparison with data from the literature. (author)

  2. Flavonoids and terpenoids from Croton muscicarpa (Euphorbiaceae)

    International Nuclear Information System (INIS)

    Barreto, Milena B.; Gomes, Clêrton L.; Freitas, João Vito B. de; Pinto, Francisco das Chagas L.; Silveira, Edilberto R.; Gramosa, Nilce V.; Torres, Daniela S. Carneiro

    2013-01-01

    A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Müll.. Arg.. Their structures were identified as the terpenoids 6α-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4’-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4’-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, 1 H and 13 C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY) and comparison with data from the literature. (author)

  3. [Study on Flavonoids in Buddleja lindleyana Fruits].

    Science.gov (United States)

    Yu, Hao; Ren, Ya-shuo; Wu, De-ling; Xu, Feng-qing; Zhang, Wei

    2015-04-01

    To study the flavonoids in the fruits of Buddleja lindleyana. The compounds were separated by repeated silica gel, RP-18 and Sephadex LH-20. Their structures were elucidated on the basis of chemical evidence and spectral data. Five flavonoids were isolated and identified as luteolin (1), tricin (2), acacetin (3), acacetin-7-O-β-D-glucopyranoside (4) and linarin(5). Compounds 3,4 and 5 are isolated from fruits of Buddleja lindleyana for the first time. Compound 2 is isolated from fruits of Buddleja lindleyana for the first time.

  4. Quantitation of flavonoid constituents in citrus fruits.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

    1999-09-01

    Twenty-four flavonoids have been determined in 66 Citrus species and near-citrus relatives, grown in the same field and year, by means of reversed phase high-performance liquid chromatography analysis. Statistical methods have been applied to find relations among the species. The F ratios of 21 flavonoids obtained by applying ANOVA analysis are significant, indicating that a classification of the species using these variables is reasonable to pursue. Principal component analysis revealed that the distributions of Citrus species belonging to different classes were largely in accordance with Tanaka's classification system.

  5. Flavonoides e terpenoides de Croton muscicarpa (Euphorbiaceae

    Directory of Open Access Journals (Sweden)

    Milena B. Barreto

    2013-01-01

    Full Text Available A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Müll. Arg.. Their structures were identified as the terpenoids 6α-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4'-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4'-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, ¹H and 13C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY and comparison with data from the literature.

  6. Flavonoids and terpenoids from Croton muscicarpa (Euphorbiaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Milena B.; Gomes, Clerton L.; Freitas, Joao Vito B. de; Pinto, Francisco das Chagas L.; Silveira, Edilberto R.; Gramosa, Nilce V., E-mail: nilce@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Centro de Ciencias, Universidade Federal do Ceara, Fortaleza (Brazil); Torres, Daniela S. Carneiro [Departamento de Ciencias Biologicas Jequie, Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil)

    2013-09-01

    A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Muell.. Arg.. Their structures were identified as the terpenoids 6{alpha}-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4'-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4'-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, {sup 1}H and {sup 13}C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY) and comparison with data from the literature. (author)

  7. Strains for the production of flavonoids from glucose

    Energy Technology Data Exchange (ETDEWEB)

    Stephanopoulos, Gregory; Santos, Christine; Koffas, Mattheos

    2015-11-13

    The invention relates to the production of flavonoids and flavonoid precursors in cells through recombinant expression of tyrosine ammonia lyase (TAL), 4-coumarate:CoA ligase (4CL), chalcone synthase (CHS), and chalcone isomerase (CHI).

  8. Protective effects of flavonoids from corn silk on oxidative stress ...

    African Journals Online (AJOL)

    Protective effects of flavonoids from corn silk on oxidative stress induced by ... The present study aims at exploring the effects of flavonoids from corn silk (FCS) on oxidative stress induced by exhaustive exercise in mice. ... from 32 Countries:.

  9. Theoretical study of isomerization and decomposition of propenal

    International Nuclear Information System (INIS)

    Chin, Chih-Hao; Lee, Shih-Huang

    2011-01-01

    We investigated the dynamics of isomerization and multi-channel dissociation of propenal (CH 2 CHCHO), methyl ketene (CH 3 CHCO), hydroxyl propadiene (CH 2 CH 2 CHOH), and hydroxyl cyclopropene (cyclic-C 3 H 3 -OH) in the ground potential-energy surface using quantum-chemical calculations. Optimized structures and vibrational frequencies of molecular species were computed with method B3LYP/6-311G(d,p). Total energies of molecules at optimized structures were computed at the CCSD(T)/6-311+G(3df,2p) level of theory. We established the potential-energy surface for decomposition to CH 2 CHCO + H, CH 2 CH + HCO, CH 2 CH 2 /CH 3 CH + CO, CHCH/CH 2 C + H 2 CO, CHCCHO/CH 2 CCO + H 2 , CHCH + CO + H 2 , CH 3 + HCCO, CH 2 CCH + OH, and CH 2 CC/cyclic-C 3 H 2 + H 2 O. Microcanonical rate coefficients of various reactions of trans-propenal with internal energies 148 and 182 kcal mol -1 were calculated using Rice-Ramsperger-Kassel-Marcus and Variational transition state theories. Product branching ratios were derivable using numerical integration of kinetic master equations and the steady-state approximation. The concerted three-body dissociation of trans-propenal to fragments C 2 H 2 + CO + H 2 is the prevailing channel in present calculations. In contrast, C 3 H 3 O + H, C 2 H 3 + HCO and C 2 H 4 + CO were identified as major channels in the photolysis of trans-propenal. The discrepancy between calculations and experiments in product branching ratios indicates that the three major photodissociation channels occur mainly on an excited potential-energy surface whereas the other channels occur mainly on the ground potential-energy surface. This work provides profound insight in the mechanisms of isomerization and multichannel dissociation of the system C 3 H 4 O.

  10. Ti-Catalyzed Selective Isomerization of Terminal Mono-substituted Olefins

    International Nuclear Information System (INIS)

    Lee, Hyung Soo; Lee, Gab Yong

    2005-01-01

    The isomerization of olefins occurs either by a metal hydride addition-elimination or by a π-allyl metal hydride intermediate. HCo(CO) 4 , [(C 2 H 4 ) 2 RhCl] 2 , Ni[P(OEt) 3 ] 4 , and PtCl 2 (PPh 3 ) 2 -SnCl 2 are effective catalysts for isomerization of olefins via a metal hydride addition-elimination mechanism, 3,4 and Fe 3 (CO) 12 catalyzed isomerization of 3-ethyl-1-pentene and isomerization of 1-heptene catalyzed by (PhCN) 2 PdCl 2 occur via a π-allyl metal hydride mechanism. The cis/trans ratio of 2-butene obtained from isomerization of 1-butene by RhH(CO)(PPh 3 ) 3 has also been investigated. The skeletal isomerization of olefins catalyzed by (R 3 P) 2 NiCl 2 is developed such as conversion of cis-1,4-hexadiene to trans-2-methyl-1,3-pentadiene. Titanium complexes serve as an effective catalysts for a variety of reactions such as hydroalumination, hydroboration, and hydrogenation of unsaturated hydrocarbons. We have been interested in the selective reactions of unsaturated hydrocarbons by using titanium and zirconium compounds. The reagent system composed of LiAlH 4 /Cp 2 TiCl 2 ≤ 2 in the molar ratio promotes the isomerization of 1-octene, but the detailed reaction for isomerization of olefins has not been reported. We report here a selective isomerization of olefins with low valent titanium complex generated from Cp 2 TiCl 2 (Cp=cyclopentadienyl) and LiAlH 4

  11. Scope and mechanism in palladium-catalyzed isomerizations of highly substituted allylic, homoallylic, and alkenyl alcohols.

    Science.gov (United States)

    Larionov, Evgeny; Lin, Luqing; Guénée, Laure; Mazet, Clément

    2014-12-03

    Herein we report the palladium-catalyzed isomerization of highly substituted allylic alcohols and alkenyl alcohols by means of a single catalytic system. The operationally simple reaction protocol is applicable to a broad range of substrates and displays a wide functional group tolerance, and the products are usually isolated in high chemical yield. Experimental and computational mechanistic investigations provide complementary and converging evidence for a chain-walking process consisting of repeated migratory insertion/β-H elimination sequences. Interestingly, the catalyst does not dissociate from the substrate in the isomerization of allylic alcohols, whereas it disengages during the isomerization of alkenyl alcohols when additional substituents are present on the alkyl chain.

  12. New isomeric states in 152,154,156Nd produced by spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Phan, X.H.; Theisen, C.; Belier, G.; Girod, M.; Meot, V.; Peru, S.; Astier, A.; Ducroux, L.; Meyer, M.; Redon, N.

    1998-01-01

    Isomeric states have been observed in fission-fragments produced by spontaneous fission of 252 Cf. These states are found in neutron rich nuclei of different structure and deformations. About 50 isomeric nuclei have been observed using coincidences between γ-rays identified in EUROGAM II and fission fragments detected in photovoltaic cells (SAPhIR). Lifetimes in the range from 20 ns to 2μs have been measured. Presented calculations based on HFB+D1S force on new measured isomeric states in the 152,154,156 Nd show evidence for K-isomers. (orig.)

  13. Isomerization of glucose into fructose by environmentally friendly Fe/β zeolite catalysts.

    Science.gov (United States)

    Xu, Siquan; Zhang, Lei; Xiao, Kehao; Xia, Haian

    2017-06-29

    Herein, the environmentally friendly Fe/β zeolite for glucose isomerization to fructose in aqueous media was reported for the first time. The effects of various reaction conditions including reaction temperature, reaction time, catalyst dosage, etc. on the isomerization reaction over Fe/β zeolite were studied in detail. Under the optimized conditions, yield of fructose higher than 20% were obtained. Moreover, the Fe/β zeolite catalysts were stable and remained constant catalytic activity after five consecutive runs. The possible active Fe species for isomerization of glucose in Fe/β zeolite is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Purification of Flavonoids from Black Currant Juice by Nanodiafiltration

    DEFF Research Database (Denmark)

    Jensen, Morten Busch; Christensen, Knud Villy; Norddahl, Birgir

    2009-01-01

      Various compounds of the flavonoid group have been reported to possess therapeutic effects towards cancer [1]. Thus there is a large potential in identifying, purifying and quantifying flavonoids from different natural sources in order to screen the pharmaceutical values of these. The flavonoid...

  15. Absorption, metabolism and health effects of dietary flavonoids in man.

    NARCIS (Netherlands)

    Hollman, P.C.H.; Katan, M.B.

    1997-01-01

    Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Over 4,000 different flavonoids have been described, and they are categorized into flavonols, flavones, catechins, flavanones, anthocyanidins and isoflavonoids. Flavonoids have a variety of biological effects in

  16. THE SYSTEMATIC AND EVOLUTIONARY SIGNIFICANCE OF EXUDATE FLAVONOIDS IN AEONIUM

    NARCIS (Netherlands)

    STEVENS, JF; HART, HT; WOLLENWEBER, E

    Leaf exudates of 32 species of Aeonium were examined for the presence of flavonoids. Thirty two flavonoids were detected in exudates of half of the species. The flavonoids were identified as methyl ethers of kaempferol, 6-hydroxykaempferol, quercetin, myricetin and scutellarein. The distribution of

  17. Genotypic variation in tree growth and selected flavonoids in leaves ...

    African Journals Online (AJOL)

    Growth and flavonoid content varied significantly among different families, and isoquercitrin was the main component of the individual flavonoids, followed by kaempferol and quercetin. Both total and individual flavonoids showed seasonal variation, with the mean highest contents of quercetin and isoquercitrin in July but the ...

  18. Flavonoid-membrane Interactions: A Protective Role of Flavonoids at the Membrane Surface?

    Directory of Open Access Journals (Sweden)

    Patricia I. Oteiza

    2005-01-01

    Full Text Available Flavonoids can exert beneficial health effects through multiple mechanisms. In this paper, we address the important, although not fully understood, capacity of flavonoids to interact with cell membranes. The interactions of polyphenols with bilayers include: (a the partition of the more non-polar compounds in the hydrophobic interior of the membrane, and (b the formation of hydrogen bonds between the polar head groups of lipids and the more hydrophilic flavonoids at the membrane interface. The consequences of these interactions are discussed. The induction of changes in membrane physical properties can affect the rates of membrane lipid and protein oxidation. The partition of certain flavonoids in the hydrophobic core can result in a chain breaking antioxidant activity. We suggest that interactions of polyphenols at the surface of bilayers through hydrogen bonding, can act to reduce the access of deleterious molecules (i.e. oxidants, thus protecting the structure and function of membranes.

  19. Interactions Between Flavonoid-Rich Extracts and Sodium Caseinate Modulate Protein Functionality and Flavonoid Bioaccessibility in Model Food Systems.

    Science.gov (United States)

    Elegbede, Jennifer L; Li, Min; Jones, Owen G; Campanella, Osvaldo H; Ferruzzi, Mario G

    2018-05-01

    With growing interest in formulating new food products with added protein and flavonoid-rich ingredients for health benefits, direct interactions between these ingredient classes becomes critical in so much as they may impact protein functionality, product quality, and flavonoids bioavailability. In this study, sodium caseinate (SCN)-based model products (foams and emulsions) were formulated with grape seed extract (GSE, rich in galloylated flavonoids) and green tea extract (GTE, rich in nongalloylated flavonoids), respectively, to assess changes in functional properties of SCN and impacts on flavonoid bioaccessibility. Experiments with pure flavonoids suggested that galloylated flavonoids reduced air-water interfacial tension of 0.01% SCN dispersions more significantly than nongalloylated flavonoids at high concentrations (>50 μg/mL). This observation was supported by changes in stability of 5% SCN foam, which showed that foam stability was increased at high levels of GSE (≥50 μg/mL, P < 0.05) but was not affected by GTE. However, flavonoid extracts had modest effects on SCN emulsion. In addition, galloylated flavonoids had higher bioaccessibility in both SCN foam and emulsion. These results suggest that SCN-flavonoid binding interactions can modulate protein functionality leading to difference in performance and flavonoid bioaccessibility of protein-based products. As information on the beneficial health effects of flavonoids expands, it is likely that usage of these ingredients in consumer foods will increase. However, the necessary levels to provide such benefits may exceed those that begin to impact functionality of the macronutrients such as proteins. Flavonoid inclusion within protein matrices may modulate protein functionality in a food system and modify critical consumer traits or delivery of these beneficial plant-derived components. The product matrices utilized in this study offer relevant model systems to evaluate how fortification with flavonoid

  20. Antidepressant screening and flavonoids isolation from ...

    African Journals Online (AJOL)

    Eremostachys laciniata (L) Bunge (Lamiaceae), a rich source of flavonoids, has been investigated for chemical constituents and in vivo antidepressant property using forced swim test (FST) model. Five important compounds were isolated, including luteolin (1), apigenin (2), 5,8-dihydroxy-6,7- dimethoxyflavone (3), 5 ...

  1. Flavonoids and platelet aggregation: A brief review.

    Science.gov (United States)

    Faggio, Caterina; Sureda, Antoni; Morabito, Silvia; Sanches-Silva, Ana; Mocan, Andrei; Nabavi, Seyed Fazel; Nabavi, Seyed Mohammad

    2017-07-15

    Platelets are small anucleated fragments derived from a megakaryocyte precursor. Platelets play a key role in many physiological functions especially in hemostasis and wound healing processes in order to maintain the integrity of the circulatory system. In addition, activated platelets release cytokines and chemokines which modulate the immune response and, in some cases of hyperactivation, they could be associated to the pathogenesis of inflammatory diseases. Flavonoids are polyphenolic compounds ubiquosly found in plants known to be potent antioxidants with positive effects against diverse diseases such as cancer, neurodegenerative or cardiovascular disease. It has been reported that some flavonoids possess anti-platelet aggregation effects though different pathways, being the inhibition of the arachidonic acid-based pathway the most representative mechanism of action. In the present review, the main sources of flavonoids, as well as their bioavailability and metabolism are summarized. Moreover, the available data about the anti-aggregation effects of flavonoids and the different mechanisms of action that has been proposed until now are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Flavonoids protecting food and beverages against light.

    Science.gov (United States)

    Huvaere, Kevin; Skibsted, Leif H

    2015-01-01

    Flavonoids, which are ubiquitously present in the plant kingdom, preserve food and beverages at the parts per million level with minor perturbation of sensory impressions. Additionally, they are safe and possibly contribute positive health effects. Flavonoids should be further exploited for the protection of food and beverages against light-induced quality deterioration through: (1) direct absorption of photons as inner filters protecting sensitive food components; (2) deactivation of (triplet-)excited states of sensitisers like chlorophyll and riboflavin; (3) quenching of singlet oxygen from type II photosensitisation; and (iv) scavenging of radicals formed as reaction intermediates in type I photosensitisation. For absorption of light, combinations of flavonoids, as found in natural co-pigmentation, facilitate dissipation of photon energy to heat thus averting photodegradation. For protection against singlet oxygen and triplet sensitisers, chemical quenching gradually decreases efficiency hence the pathway to physical quenching should be optimised through product formulation. The feasibility of these protection strategies is further supported by kinetic data that are becoming available, allowing for calculation of threshold levels of flavonoids to prevent beer and dairy products from going off. On the other hand, increasing understanding of the interplay between light and matrix physicochemistry, for example the effect of aprotic microenvironments on phototautomerisation of compounds like quercetin, opens up for engineering better light-to-heat converting channels in processed food to eventually prevent quality loss. © 2014 Society of Chemical Industry.

  3. [Contents of total flavonoids in Rhizoma Arisaematis].

    Science.gov (United States)

    Du, S S; Lin, H Y; Zhou, Y X; Wei, L X

    2001-06-01

    Comparing the contents of total flavonoides of Rhizoma Arisaematis, which collected in different time, regions, different varieties and processed. Determining the contents by ultraviolet spectro-photometry. The contents were found in the following sequence: 1. the end of July, the begin of July, August, September; 2. Beijing, Shanxi, Sichuan, Anhui; 3. Arisaema erubenscens, A. heterophyllum, A. amurense; 4. unprocessed product, processed product.

  4. Antiplasmodial and larvicidal flavonoids from Derris trifoliata

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. ABSTRACT. From the dichloromethane-methanol (1:1) extract of the seed pods of Derris trifoliata, a new flavanone derivative (S)-lupinifolin 4´-methyl ether was isolated. In addition, the known flavonoids lupinifolin and rotenone were identified. The structures were determined on the basis of spectroscopic ...

  5. Flavonoids as Inhibitors of Human Butyrylcholinesterase Variants

    Directory of Open Access Journals (Sweden)

    Maja Katalinić

    2014-01-01

    Full Text Available The inhibition of butyrylcholinesterase (BChE, EC 3.1.1.8 appears to be of interest in treating diseases with symptoms of reduced neurotransmitter levels, such as Alzheimer’s disease. However, BCHE gene polymorphism should not be neglected in research since it could have an effect on the expected outcome. Several well-known cholinergic drugs (e.g. galantamine, huperzine and rivastigmine originating from plants, or synthesised as derivatives of plant compounds, have shown that herbs could serve as a source of novel target-directed compounds. We focused our research on flavonoids, biologically active polyphenolic compounds found in many plants and plant-derived products, as BChE inhibitors. All of the tested flavonoids: galangin, quercetin, fisetin and luteolin reversibly inhibited usual, atypical, and fluoride-resistant variants of human BChE. The inhibition potency increased in the following order, identically for all three BChE variants: luteolinflavonoids exists in view of BChE polymorphism. Our results suggested that flavonoids could assist the further development of new BChE-targeted drugs for treating symptoms of neurodegenerative diseases and dementia.

  6. Flavonoid, hesperidine, total phenolic contents and antioxidant ...

    African Journals Online (AJOL)

    Additionally, the antioxidant activities were also determined by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity. C. hystrix had the highest flavonoid and total phenolic contents while C. aurantifolia had the highest hesperidine content. The antioxidant activity of ...

  7. Pectolinarigenin - A Flavonoid Compound from Cirsium Japonicum ...

    African Journals Online (AJOL)

    HP

    /tjpr.v13i2.9. Original Research Article. Pectolinarigenin - A Flavonoid Compound from Cirsium. Japonicum with Potential Anti-proliferation Activity in MCF-. 7 Breast Cancer Cell. Mingqian Lu. 1,2,3. , Qingzhi Kong. 1,4. *, Xinhua Xu. 2,3.

  8. Association among Dietary Flavonoids, Flavonoid Subclasses and Ovarian Cancer Risk: A Meta-Analysis

    Science.gov (United States)

    You, Ruxu; Yang, Yu; Liao, Jing; Chen, Dongsheng; Yu, Lixiu

    2016-01-01

    Background Previous studies have indicated that intake of dietary flavonoids or flavonoid subclasses is associated with the ovarian cancer risk, but presented controversial results. Therefore, we conducted a meta-analysis to derive a more precise estimation of these associations. Methods We performed a search in PubMed, Google Scholar and ISI Web of Science from their inception to April 25, 2015 to select studies on the association among dietary flavonoids, flavonoid subclasses and ovarian cancer risk. The information was extracted by two independent authors. We assessed the heterogeneity, sensitivity, publication bias and quality of the articles. A random-effects model was used to calculate the pooled risk estimates. Results Five cohort studies and seven case-control studies were included in the final meta-analysis. We observed that intake of dietary flavonoids can decrease ovarian cancer risk, which was demonstrated by pooled RR (RR = 0.82, 95% CI = 0.68–0.98). In a subgroup analysis by flavonoid subtypes, the ovarian cancer risk was also decreased for isoflavones (RR = 0.67, 95% CI = 0.50–0.92) and flavonols (RR = 0.68, 95% CI = 0.58–0.80). While there was no compelling evidence that consumption of flavones (RR = 0.86, 95% CI = 0.71–1.03) could decrease ovarian cancer risk, which revealed part sources of heterogeneity. The sensitivity analysis indicated stable results, and no publication bias was observed based on the results of Funnel plot analysis and Egger’s test (p = 0.26). Conclusions This meta-analysis suggested that consumption of dietary flavonoids and subtypes (isoflavones, flavonols) has a protective effect against ovarian cancer with a reduced risk of ovarian cancer except for flavones consumption. Nevertheless, further investigations on a larger population covering more flavonoid subclasses are warranted. PMID:26960146

  9. Impact of certain flavonoids on lipid profiles--potential action of Garcinia cambogia flavonoids.

    Science.gov (United States)

    Koshy, A S; Vijayalakshmi, N R

    2001-08-01

    Flavonoids from Cocos nucifera, Myristica fragrance, Saraka asoka and Garcinia cambogia exerted hypolipidaemic activity in rats. Lipid lowering activity was maximum in rats administered flavonoids (10 mg/kg BW/day) from Garcinia cambogia. A dose response study revealed biphasic activity. Higher doses were less effective in reducing lipid levels in serum and tissues, although devoid of toxic effects. Copyright 2001 John Wiley & Sons, Ltd.

  10. Flavonoids of Calligonum polygonoides and their cytotoxicity.

    Science.gov (United States)

    Ahmed, Hayam; Moawad, Abeer; Owis, Asmaa; AbouZid, Sameh; Ahmed, Osama

    2016-10-01

    Context Calligonum polygonoides L. subsp. comosum L' Hér. (Polygonaceae), locally known as "arta", is a slow-growing small leafless desert shrub. Objective Isolation, structure elucidation and evaluation of cytotoxic activity of flavonoids from C. polygonoides aerial parts. Materials and methods Flavonoids in the hydroalcoholic extract of the of C. polygonoides were isolated and purified using column chromatography and preparative HPLC. The structures of the isolated flavonoids were elucidated on the basis of spectroscopic data including 2D NMR techniques. The cytotoxic activity of the isolated flavonoids (6.25, 25, 50 and 100 μg/mL) was evaluated against liver HepG2 and breast MCF-7 cancer cell lines using sulphorhodamine-B assay. Results A new flavonoid, kaempferol-3-O-β-D-(6″-n-butyl glucuronide) (1), and 13 known flavonoids, quercetin 3-O-β-D-(6″-n-butyl glucuronide) (2), kaempferol-3-O-β-D-(6″-methyl glucuronide) (3), quercetin-3-O-β-D-(6″-methyl glucuronide) (4), quercetin-3-O-glucuronide (5), kaempferol-3-O-glucuronide (6), quercetin-3-O-α-rhamnopyranoside (7), astragalin (8), quercetin-3-O-glucopyranoside (9), taxifolin (10), (+)-catechin (11), dehydrodicatechin A (12), quercetin (13), and kaempferol (14), were isolated from the aerial parts of C. polygonoides. Quercetin showed significant cytotoxic activity against HepG2 and MCF-7 cell lines with IC50 values of 4.88 and 0.87 μg/mL, respectively. Structure-activity relationships were analyzed by comparing IC50 values of several pairs of flavonoids differing in one structural element. Discussion and conclusion The activity against breast cancer cell lines decreased by glycosylation at C-3. The presence of 2,3-double bond in ring C, carbonyl group at C-4 and 3',4'-dihydroxy substituents in ring B are essential structural requirements for the cytotoxic activity against breast cancer cells.

  11. Flavonoids and heart health: Proceedings of the ILSI North America Flavonoids Workshop may 31-june 1, 2005, Washington DC

    NARCIS (Netherlands)

    Erdman, J.W.; Balentine, D.; Arab, L.; Beecher, G.; Dwyer, J.T.; Folts, J.; Harnly, J.; Hollman, P.C.H.; Keen, C.L.; Mazza, G.; Messina, M.; Scalbert, A.; Vita, J.; Williamson, G.; Burrows, J.

    2007-01-01

    This article provides an overview of current research on flavonoids as presented during a workshop entitled, "Flavonoids and Heart Health," held by the ILSI North America Project Committee on Flavonoids in Washington, DC, May 31 and June 1, 2005. Because a thorough knowledge and understanding about

  12. Analysis of flavonoids and the flavonoid structural genes in brown fiber of upland cotton.

    Directory of Open Access Journals (Sweden)

    Hongjie Feng

    Full Text Available BACKGROUND: As a result of changing consumer preferences, cotton (Gossypium Hirsutum L. from varieties with naturally colored fibers is becoming increasingly sought after in the textile industry. The molecular mechanisms leading to colored fiber development are still largely unknown, although it is expected that the color is derived from flavanoids. EXPERIMENTAL DESIGN: Firstly, four key genes of the flavonoid biosynthetic pathway in cotton (GhC4H, GhCHS, GhF3'H, and GhF3'5'H were cloned and studied their expression profiles during the development of brown- and white cotton fibers by QRT-PCR. And then, the concentrations of four components of the flavonoid biosynthetic pathway, naringenin, quercetin, kaempferol and myricetin in brown- and white fibers were analyzed at different developmental stages by HPLC. RESULT: The predicted proteins of the four flavonoid structural genes corresponding to these genes exhibit strong sequence similarity to their counterparts in various plant species. Transcript levels for all four genes were considerably higher in developing brown fibers than in white fibers from a near isogenic line (NIL. The contents of four flavonoids (naringenin, quercetin, kaempferol and myricetin were significantly higher in brown than in white fibers and corresponding to the biosynthetic gene expression levels. CONCLUSIONS: Flavonoid structural gene expression and flavonoid metabolism are important in the development of pigmentation in brown cotton fibers.

  13. Direct Measurement of the Isomerization Barrier of the Isolated Retinal Chromophore

    DEFF Research Database (Denmark)

    Dilger, Jonathan; Musbat, Lihi; Sheves, Mordechai

    2015-01-01

    Isomerizations of the retinal chromophore were investigated using the IMS-IMS technique. Four different structural features of the chromophore were observed, isolated, excited collisionally, and the resulting isomer and fragment distributions were measured. By establishing the threshold activatio...

  14. Glucose Isomerization by Enzymes and Chemo-catalysts: Status and Current Advances

    DEFF Research Database (Denmark)

    Li, Hu; Yang, Song; Saravanamurugan, Shunmugavel

    2017-01-01

    of isomerization of aldoses in terms of yields, catalysts, solvents, catalytic systems, etc., by both enzymatic and chemo-catalytic approaches. Among aldose ketose interconversion reactions, fructose production by glucose isomerization to make high-fructose corn syrup (HFCS) is an industrially important and large....../intermediate fructose. This review focuses on how both enzyme and chemo-catalysts are being useful for the isomerization of glucose to fructose. Specifically, development of Lewis acid containing zeolites for glucose isomerization is reviewed in detail, including mechanism, isotopic labeling, and computational studies....... biocatalytic process today, and a large number of studies have been reported on the process development. In parallel, also alternative chemo-catalytic systems have emerged, as enzymatic conversion has drawbacks, though they are typically more selective and produce fructose under mild reaction conditions...

  15. Potential ecological roles of flavonoids from Stellera chamaejasme.

    Science.gov (United States)

    Yan, Zhiqiang; Zeng, Liming; Jin, Hui; Qin, Bo

    2015-01-01

    Stellera chamaejasme L. (Thymelaeaceae), a perennial weed, distributes widely in the grasslands of Russia, Mongolia and China. The plant synthesizes various secondary metabolites including a group of flavonoids. To our knowledge, flavonoids play important roles in the interactions between plants and the environment. So, what are the benefits to S. chamaejasme from producing these flavonoids? Here, we discuss the potential ecological role of flavonoids from S. chamaejasme in protecting the plant from insects and other herbivores, as well as pathogens and competing plant species, and new data are provided on the phytotoxicity of flavonoids from S. chamaejasme toward Poa annua L.

  16. Mechanistic features of isomerizing alkoxycarbonylation of methyl oleate

    KAUST Repository

    Roesle, Philipp

    2012-10-24

    The weakly coordinated triflate complex [(P̂P)Pd(OTf)] +(OTf)- (1) (P̂P = 1,3-bis(di-tert- butylphosphino)propane) is a suitable reactive precursor for mechanistic studies of the isomerizing alkoxcarbonylation of methyl oleate. Addition of CH 3OH or CD3OD to 1 forms the hydride species [(P ̂P)PdH(CH3OH)]+(OTf)- (2-CH3OH) or the deuteride [(P̂P)PdD(CD 3OD)]+(OTf)- (2D-CD3OD), respectively. Further reaction with pyridine cleanly affords the stable and isolable hydride [(P̂P)PdH(pyridine)]+(OTf) - (2-pyr). This complex yields the hydride fragment free of methanol by abstraction of pyridine with BF3OEt2, and thus provides an entry to mechanistic observations including intermediates reactive toward methanol. Exposure of methyl oleate (100 equiv) to 2D-CD 3OD resulted in rapid isomerization to the thermodynamic isomer distribution, 94.3% of internal olefins, 5.5% of α,β-unsaturated ester and <0.2% of terminal olefin. Reaction of 2-pyr/BF3OEt 2 with a stoichiometric amount of 1-13C-labeled 1-octene at -80 °C yields a 50:50 mixture of the linear alkyls [(P ̂P)Pd13CH2(CH2) 6CH3]+ and [(P̂P)PdCH 2(CH2)6 13CH3] + (4a and 4b). Further reaction with 13CO yields the linear acyls [(P̂P)Pd13C(=O)12/13CH 2(CH2)6 12/13CH3(L)] + (5-L; L = solvent or 13CO). Reaction of 2-pyr/BF 3·OEt2 with a stoichiometric amount of methyl oleate at -80 °C also resulted in fast isomerization to form a linear alkyl species [(P̂P)PdCH2(CH2) 16C(=O)OCH3]+ (6) and a branched alkyl stabilized by coordination of the ester carbonyl group as a four membered chelate [(P̂P)PdCH{(CH2)15CH 3}C(=O)OCH3]+ (7). Addition of carbon monoxide (2.5 equiv) at -80 °C resulted in insertion to form the linear acyl carbonyl [(P̂P)PdC(=O)(CH2)17C(=O)OCH 3(CO)]+ (8-CO) and the five-membered chelate [(P ̂P)PdC(=O)CH{(CH2)15CH3}C(=O) OCH3]+ (9). Exposure of 8-CO and 9 to 13CO at -50 °C results in gradual incorporation of the 13C label. Reversibility of 7 + CO ⇄ 9 is also evidenced by ΔG = -2.9 kcal mol-1 and

  17. Effects of alkali or acid treatment on the isomerization of amino acids.

    Science.gov (United States)

    Ohmori, Taketo; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

    2012-10-01

    The effect of alkali treatment on the isomerization of amino acids was investigated. The 100×D/(D+L) values of amino acids from peptide increased with increase in the number of constituent amino acid residues. Furthermore, the N-terminal amino acid of a dipeptide was isomerized to a greater extent than the C-terminal residue. Copyright © 2012. Published by Elsevier B.V.

  18. Metode Cepat Identifikasi Flavonoid dari Daun Ocimum sanctum L. (Selasih

    Directory of Open Access Journals (Sweden)

    Diah Dhianawaty

    2012-03-01

    Full Text Available A plant’s effectiveness as a herbal drug comes from its chemical content such as flavonoids. Flavonoids are useful for human body health. Therefore flavonoids content can be used as a marker from the usefulness of a plant, and rapid identification method of flavonoid is needed. The objective of the research was to get a rapid method of flavonoid content identification from Ocimum sanctum. The extraction, isolation and identification of flavonoids from Ocimum sanctum leaves has been done at Medical Chemistry laboratory Faculty of Medicine Universitas Padjadjaran in 2005. Flavonoids were extracted continually by 95% ethanol, were isolated with paper chromatography/cellulose TLC and 2% acetic acid, then continued with elucidation reagents: n-butanol–acetic acid–water, chloroform–acetic acid–water, forestall, 5%, 15%, 35% and 50% acetic acids. Flavonoids were identified with diagnostic reagents and ultraviolet light. Isolation with 2% and 35% acetic acids respectively gave two spots of flavonoids as flavon, FOAc-1 had Rf=0.69 and FOAc-2 had Rf=0.57. The other elucidation reagents gave one spot of flavonoid. In conclusion, isolation with 2% and 35% acetic acids respectively and identification with diagnostic reagent and ultraviolet light is a rapid method for identification of flavonoids content in Ocimum sanctum

  19. Natural Flavonoids as Promising Analgesic Candidates: A Systematic Review.

    Science.gov (United States)

    Xiao, Xiao; Wang, Xiaoyu; Gui, Xuan; Chen, Lu; Huang, Baokang

    2016-11-01

    Due to the chemical structural diversity and various analgesic mechanisms, an increasing number of studies indicated that some flavonoids from medicinal plants could be promising candidates for new natural analgesic drugs, which attract high interests of advanced users and academic researchers. The aim of this systematic review is to report flavonoids and its derivatives as new analgesic candidates based on the pharmacological evidences. Sixty-four papers were found concerning the potential analgesic activity of 46 flavonoids. In this case, the evidence for analgesic activity of flavonoids and total flavonoids was investigated. Meanwhile, the corresponding analgesic mechanism of flavonoids was discussed by generalizing and analyzing the current publications. Based on this review, the conclusion can be drawn that some flavonoids are promising candidates for painful conditions and deserve particular attention in further research and development. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

  20. Bioavailability, metabolism and potential health protective effects of dietary flavonoids

    DEFF Research Database (Denmark)

    Bredsdorff, Lea

    Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several...... epidemiological studies but the evidence is inconclusive. One major obstacle for epidemiological studies investigating associations between flavonoid intake and risk of CHD is the estimation of flavonoid intake. There is a vast variety of flavonoids in commonly eaten food products but only limited knowledge...... of their content. In addition, variation in individual metabolic genotype and microflora may greatly affect the actual flavonoid exposure. The preventive effects of flavonoids on CHD are mainly ascribed to their anti-inflammatory and antioxidant activities. Several mechanisms of anti-inflammatory and antioxidant...

  1. Genetic diversity of flavonoid content in leaf of hawthorn resources

    International Nuclear Information System (INIS)

    Zhao, Y.; Wang, G.; Liu, Z.

    2014-01-01

    Hawthorn (Cratageus spp.) are important medicinal plants. Flavonoids are the main active ingredient in hawthorn. With the help of hawthorn leaf flavonoids efficient detection system, vitexin, rhamnosylvitexin, hyperin, rutin and quercetin of 122 hawthorn resources was precisely measured.The flavonoid contents of 10 hawthorn species were explicited. The comparation of flavonoids revealed the abundant genetic diversity of hawthorn flavones. Large variable coefficient has been observed among 5 flavonoid monomer traits. The coefficients of variation were 44.17%, 132.2%, 157.08%, 113.91% and 31.05 for Vitexin, Rhamnosylvitexin, Hyperoside, Rutin and Quercetin respectively. The sum of these 5 flavonoid monomer contents represented the total flavonoids in hawthorn. The total coefficients of variation was 44.01%. Some high-content-flavone and valuable leaf resources were found. This research could provide accurate date for further production, breeding and the effective use of medicinal resources. (author)

  2. Thermal decomposition and isomerization of cis-permethrin and beta-cypermethrin in the solid phase.

    Science.gov (United States)

    González Audino, Paola; Licastro, Susana A; Zerba, Eduardo

    2002-02-01

    The stability to heart of cis-permethrin and beta-cypermethrin in the solid phase was studied and the decomposition products identified. Samples heated at 210 degrees C in an oven in the dark showed that, in the absence of potassium chlorate (the salt present in smoke-generating formulations of these pyrethroids), cis-permethrin was not isomerized, although in the presence of that salt, decomposition was greater and thermal isomerization occurred. Other salts of the type KXO3 or NaXO3, with X being halogen or nitrogen, also led to a considerable thermal isomerization. Heating the insecticides in solution in the presence of potassium chlorate did not produce isomerization in any of the solvents assayed. Salt-catalysed thermal cis-trans isomerization was also found for other pyrethroids derived from permethrinic or deltamethrinic acid but not for those derived from chrysanthemic acid. The main thermal degradation processes of cis-permethrin and beta-cypermethrin decomposition when potassium chlorate was present were cyclopropane isomerization, ester cleavage and subsequent oxidation of the resulting products. Permethrinic acid, 3-phenoxybenzyle chloride, alcohol, aldehyde and acid were identified in both cases, as well as 3-phenoxybenzyl cyanide from beta-cypermethrin. A similar decomposition pattern occurred after combustion of pyrethroid fumigant formulations.

  3. Molecular and excited state properties of isomeric scarlet disperse dyes

    Science.gov (United States)

    Lim, Jihye; Szymczyk, Malgorzata; Mehraban, Nahid; Ding, Yi; Parrillo-Chapman, Lisa; El-Shafei, Ahmed; Freeman, Harold S.

    2018-06-01

    This work was part of an investigation aimed at characterizing the molecular and excited state properties of currently available disperse dyes developed to provide stability to extensive sunlight exposures when adsorbed on poly(ethylene terephthalate) (PET) fibers. Having completed the characterization of yellow, magenta, and cyan disperse dyes for PET-based fabrics used outdoors, our attention turned to the colors designed to enhance the color gamut of a standard 4-member (cyan/yellow/magenta/black) color set. The present study pertained specifically to the characterization of commercially available scarlet dyes. In this regard, HPLC analysis showed that a scarlet product used for PET coloration was mainly a 70/30 mixture of dyes, and the use of HRMS and single crystal X-ray diffraction analyses indicated that these two dyes were azo compounds derived from isomeric pyridine-based couplers which differed in the location of the primary amino (sbnd NH2) and anilino (sbnd NHPh) groups attached to the pyridine ring. One dye structure has the sbnd NHPh group para to the azo group (Sc2), while the other has that group in the ortho position (Sc3). The presence of either ortho substituent provides photostabilization through intramolecular H-bonding with the azo moiety. Further, results from molecular modeling studies showed that the lower excited state oxidation potential of Sc3 relative to that of Sc2 allows Sc3 to function as an energy quencher for the excited state of Sc2 - through thermodynamically favorable electron transfer.

  4. Isomeric shift compensation when using resonance detectors in Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Irkaev, S.M.; Semenkin, V.A.; Sokolov, M.M.

    1981-01-01

    Method for compensation of isomeric shift of lines observed during operation of resonance detectors being part of spectrometers of nuclear gamma resonance is suggested. A flowsheet of device permitting to realize the method described is given. The method is based on using the Doppler effect. A source of resonance radiation is moved at a constant velocity, which is choosen so as to compensate energy shift of lines of the source and convertors of the resonance detector. The absorber under investigation is put in motion with a constant acceleration. The resonance detector signals are amplified selected according to amplitude by a discriminator and come to the input of multichannel analyzer operating in the regime of subsequent scaling. Analysis of experimental spectra obtained at velocities of source movement from 0 to +3 mm/s shows that value of resonance absorption effect drops as increasing energy shift in the source-converter system. It is concluded that application of the method described will permit to considerably extend the field of application of resonance detectors in the Moessbauer spectroscopy and investigate in practice all the isotopes having converted transitions [ru

  5. Flavonoides e sesquiterpenos de Croton pedicellatus Kunth

    OpenAIRE

    Lopes, Elton Luz; Andrade Neto, Manoel; Silveira, Edilberto Rocha; Pessoa, Otilia Deusdênia Loiola; Braz-Filho, Raimundo

    2012-01-01

    The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6"-O-p-coumaroyl-β-galactopyranosyl- kaempferol, 6"-O-p-coumaroyl-β-glucopyranosyl-3"-methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric method...

  6. Chemistry and Biological Activities of Flavonoids: An Overview

    Science.gov (United States)

    Kumar, Shashank; Pandey, Abhay K.

    2013-01-01

    There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production. PMID:24470791

  7. Citrus Flavonoids as Regulators of Lipoprotein Metabolism and Atherosclerosis.

    Science.gov (United States)

    Mulvihill, Erin E; Burke, Amy C; Huff, Murray W

    2016-07-17

    Citrus flavonoids are polyphenolic compounds with significant biological properties. This review summarizes recent advances in understanding the ability of citrus flavonoids to modulate lipid metabolism, other metabolic parameters related to the metabolic syndrome, and atherosclerosis. Citrus flavonoids, including naringenin, hesperitin, nobiletin, and tangeretin, have emerged as potential therapeutics for the treatment of metabolic dysregulation. Epidemiological studies reveal an association between the intake of citrus flavonoid-containing foods and a decreased incidence of cardiovascular disease. Studies in cell culture and animal models, as well as a limited number of clinical studies, reveal the lipid-lowering, insulin-sensitizing, antihypertensive, and anti-inflammatory properties of citrus flavonoids. In animal models, supplementation of rodent diets with citrus flavonoids prevents hepatic steatosis, dyslipidemia, and insulin resistance primarily through inhibition of hepatic fatty acid synthesis and increased fatty acid oxidation. Citrus flavonoids blunt the inflammatory response in metabolically important tissues including liver, adipose, kidney, and the aorta. The mechanisms underlying flavonoid-induced metabolic regulation have not been completely established, although several potential targets have been identified. In mouse models, citrus flavonoids show marked suppression of atherogenesis through improved metabolic parameters as well as through direct impact on the vessel wall. Recent studies support a role for citrus flavonoids in the treatment of dyslipidemia, insulin resistance, hepatic steatosis, obesity, and atherosclerosis. Larger human studies examining dose, bioavailability, efficacy, and safety are required to promote the development of these promising therapeutic agents.

  8. Chemistry and Biological Activities of Flavonoids: An Overview

    Directory of Open Access Journals (Sweden)

    Shashank Kumar

    2013-01-01

    Full Text Available There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production.

  9. A Novel Technique that Enables Efficient Conduct of Simultaneous Isomerization and Fermentation (SIF) of Xylose

    Science.gov (United States)

    Rao, Kripa; Chelikani, Silpa; Relue, Patricia; Varanasi, Sasidhar

    Of the sugars recovered from lignocellulose, D-glucose can be readily converted into ethanol by baker's or brewer's yeast (Saccharomyces cerevisiae). However, xylose that is obtained by the hydrolysis of the hemicellulosic portion is not fermentable by the same species of yeasts. Xylose fermentation by native yeasts can be achieved via isomerization of xylose to its ketose isomer, xylulose. Isomerization with exogenous xylose isomerase (XI) occurs optimally at a pH of 7-8, whereas subsequent fermentation of xylulose to ethanol occurs at a pH of 4-5. We present a novel scheme for efficient isomerization of xylose to xylulose at conditions suitable for the fermentation by using an immobilized enzyme system capable of sustaining two different pH microenvironments in a single vessel. The proof-of-concept of the two-enzyme pellet is presented, showing conversion of xylose to xylulose even when the immobilized enzyme pellets are suspended in a bulk solution whose pH is sub-optimal for XI activity. The co-immobilized enzyme pellets may prove extremely valuable in effectively conducting "simultaneous isomerization and fermentation" (SIF) of xylose. To help further shift the equilibrium in favor of xylulose formation, sodium tetraborate (borax) was added to the isomerization solution. Binding of tetrahydroxyborate ions to xylulose effectively reduces the concentration of xylulose and leads to increased xylose isomerization. The formation of tetrahydroxyborate ions and the enhancement in xylulose production resulting from the complexation was studied at two different bulk pH values. The addition of 0.05 M borax to the isomerization solution containing our co-immobilized enzyme pellets resulted in xylose to xylulose conversion as high as 86% under pH conditions that are suboptimal for XI activity. These initial findings, which can be optimized for industrial conditions, have significant potential for increasing the yield of ethanol from xylose in an SIF approach.

  10. Tin-containing zeolites are highly active catalysts for the isomerization of glucose in water.

    Science.gov (United States)

    Moliner, Manuel; Román-Leshkov, Yuriy; Davis, Mark E

    2010-04-06

    The isomerization of glucose into fructose is a large-scale reaction for the production of high-fructose corn syrup (HFCS; reaction performed by enzyme catalysts) and recently is being considered as an intermediate step in the possible route of biomass to fuels and chemicals. Here, it is shown that a large-pore zeolite that contains tin (Sn-Beta) is able to isomerize glucose to fructose in aqueous media with high activity and selectivity. Specifically, a 10% (wt/wt) glucose solution containing a catalytic amount of Sn-Beta (150 Sn:glucose molar ratio) gives product yields of approximately 46% (wt/wt) glucose, 31% (wt/wt) fructose, and 9% (wt/wt) mannose after 30 min and 12 min of reaction at 383 K and 413 K, respectively. This reactivity is achieved also when a 45 wt% glucose solution is used. The properties of the large-pore zeolite greatly influence the reaction behavior because the reaction does not proceed with a medium-pore zeolite, and the isomerization activity is considerably lower when the metal centers are incorporated in ordered mesoporous silica (MCM-41). The Sn-Beta catalyst can be used for multiple cycles, and the reaction stops when the solid is removed, clearly indicating that the catalysis is occurring heterogeneously. Most importantly, the Sn-Beta catalyst is able to perform the isomerization reaction in highly acidic, aqueous environments with equivalent activity and product distribution as in media without added acid. This enables Sn-Beta to couple isomerizations with other acid-catalyzed reactions, including hydrolysis/isomerization or isomerization/dehydration reaction sequences [starch to fructose and glucose to 5-hydroxymethylfurfural (HMF) demonstrated here].

  11. Flavonoids from each of the six structural groups reactivate BRM, a possible cofactor for the anticancer effects of flavonoids

    Science.gov (United States)

    Kahali, Bhaskar; Marquez, Stefanie B.; Thompson, Kenneth W.; Yu, Jinlong; Gramling, Sarah J.B.; Lu, Li; Aponick, Aaron; Reisman, David

    2014-01-01

    Flavonoids have been extensively studied and are well documented to have anticancer effects, but it is not entirely known how they impact cellular mechanisms to elicit these effects. In the course of this study, we found that a variety of different flavonoids readily restored Brahma (BRM) in BRM-deficient cancer cell lines. Flavonoids from each of the six different structural groups were effective at inducing BRM expression as well as inhibiting growth in these BRM-deficient cancer cells. By blocking the induction of BRM with shRNA, we found that flavonoid-induced growth inhibition was BRM dependent. We also found that flavonoids can restore BRM functionality by reversing BRM acetylation. In addition, we observed that an array of natural flavonoid-containing products both induced BRM expression as well as deacetylated the BRM protein. We also tested two of the BRM-inducing flavonoids (Rutin and Diosmin) at both a low and a high dose on the development of tumors in an established murine lung cancer model. We found that these flavonoids effectively blocked development of adenomas in the lungs of wild-type mice but not in that of BRMnull mice. These data demonstrate that BRM expression and function are regulated by flavonoids and that functional BRM appears to be a prerequisite for the anticancer effects of flavonoids both in vitro and in vivo. PMID:24876151

  12. Transgenic rice seed expressing flavonoid biosynthetic genes accumulate glycosylated and/or acylated flavonoids in protein bodies

    Science.gov (United States)

    Ogo, Yuko; Mori, Tetsuya; Nakabayashi, Ryo; Saito, Kazuki; Takaiwa, Fumio

    2016-01-01

    Plant-specialized (or secondary) metabolites represent an important source of high-value chemicals. In order to generate a new production platform for these metabolites, an attempt was made to produce flavonoids in rice seeds. Metabolome analysis of these transgenic rice seeds using liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry was performed. A total of 4392 peaks were detected in both transgenic and non-transgenic rice, 20–40% of which were only detected in transgenic rice. Among these, 82 flavonoids, including 37 flavonols, 11 isoflavones, and 34 flavones, were chemically assigned. Most of the flavonols and isoflavones were O-glycosylated, while many flavones were O-glycosylated and/or C-glycosylated. Several flavonoids were acylated with malonyl, feruloyl, acetyl, and coumaroyl groups. These glycosylated/acylated flavonoids are thought to have been biosynthesized by endogenous rice enzymes using newly synthesized flavonoids whose biosynthesis was catalysed by exogenous enzymes. The subcellular localization of the flavonoids differed depending on the class of aglycone and the glycosylation/acylation pattern. Therefore, flavonoids with the intended aglycones were efficiently produced in rice seeds via the exogenous enzymes introduced, while the flavonoids were variously glycosylated/acylated by endogenous enzymes. The results suggest that rice seeds are useful not only as a production platform for plant-specialized metabolites such as flavonoids but also as a tool for expanding the diversity of flavonoid structures, providing novel, physiologically active substances. PMID:26438413

  13. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Hooper, Lee; Kroon, Paul A; Rimm, Eric B; Cohn, Jeffrey S; Harvey, Ian; Le Cornu, Kathryn A; Ryder, Jonathan J; Hall, Wendy L; Cassidy, Aedín

    2008-07-01

    The beneficial effects of flavonoid consumption on cardiovascular risk are supported by mechanistic and epidemiologic evidence. We aimed to systematically review the effectiveness of different flavonoid subclasses and flavonoid-rich food sources on cardiovascular disease (CVD) and risk factors--ie, lipoproteins, blood pressure, and flow-mediated dilatation (FMD). Methods included a structured search strategy on MEDLINE, EMBASE, and Cochrane databases; formal inclusion or exclusion, data extraction, and validity assessment; and meta-analysis. One hundred thirty-three trials were included. No randomized controlled trial studied effects on CVD morbidity or mortality. Significant heterogeneity confirmed differential effects between flavonoid subclasses and foods. Chocolate increased FMD after acute (3.99%; 95% CI: 2.86, 5.12; 6 studies) and chronic (1.45%; 0.62, 2.28; 2 studies) intake and reduced systolic (-5.88 mm Hg; -9.55, -2.21; 5 studies) and diastolic (-3.30 mm Hg; -5.77, -0.83; 4 studies) blood pressure. Soy protein isolate (but not other soy products or components) significantly reduced diastolic blood pressure (-1.99 mm Hg; -2.86, -1.12; 9 studies) and LDL cholesterol (-0.19 mmol/L; -0.24, -0.14; 39 studies). Acute black tea consumption increased systolic (5.69 mm Hg; 1.52, 9.86; 4 studies) and diastolic (2.56 mm Hg; 1.03, 4.10; 4 studies) blood pressure. Green tea reduced LDL (-0.23 mmol/L; -0.34, -0.12; 4 studies). For many of the other flavonoids, there was insufficient evidence to draw conclusions about efficacy. To date, the effects of flavonoids from soy and cocoa have been the main focus of attention. Future studies should focus on other commonly consumed subclasses (eg, anthocyanins and flavanones), examine dose-response effects, and be of long enough duration to allow assessment of clinically relevant endpoints.

  14. Thermal isomerization of regiospecifically 10B-labeled icosahedral carboranes

    International Nuclear Information System (INIS)

    Edvenson, G.M.; Gaines, D.F.

    1990-01-01

    Thermal treatment of regiospecifically 10 B-enriched (96%) 3-( 10 B)-1,2-C 2 n B 9 H 12 and 2-( 10 B)-1,7-C 2 n B 9 H 12 ( n B = boron with normal isotopic abundances) followed by 10 B and 11 B NMR analysis reveal that (1) 3-( 10 B)-1,2-C 2 n B 9 H 12 undergoes rearrangements that completely scramble the enriched boron atom, (2) these rearrangements occur at a rate faster than the conversion of 1,2-C 2 B 10 H 12 to 1,7-C 2 B 10 H 12 , (3) the 1,7-C 2 B 10 H 12 that is formed does not re-form 1,2-C 2 B 10 H 12 at a detectable rate, and (4) at temperatures at which 1,2-C 2 B 10 H 12 forms 1,7-C 2 B 10 H 12 at a significant rate, the latter undergoes no further rearrangements. The movement of 10 B at 350 degree C in 1,2-C 2 B 10 H 12 is compared to the movement predicted by various isomerization mechanisms. The mechanism that appears to give the closest agreement involves a 12-vertex nido intermediate. It was found that a number of previously considered mechanisms, including simple exchange between two boron sites, triangular face rotation in an icosahedron, diamond-square-diamond twist, and rotation of pentagonal pyramids, are extensions of the nido intermediate mechanism. The synthesis and thermal rearrangement of 3-F-3-( 10 B)-1,2-C 2 n B 9 H 11 demonstrate that independent intramolecular fluorine migration does not occur during rearrangement. 27 refs., 7 figs

  15. Highly Oxygenated Flavonoids from the Leaves of Nicotiana plumbaginifolia (Solanaceae)

    OpenAIRE

    Md. Shafiullah Shajib; Bidyut Kanti Datta; Md. Hossain Sohrab; Mohammad Abdur Rashid; Lutfun Nahar; Satyajit Dey Sarker

    2017-01-01

    Nicotiana plumbaginifolia Viv. is an annual herb of the family Solanaceae, which grows abundantly in the weedy lands of Bangladesh . This plant possesses analgesic, antibacterial, anti-anxiety and hepatoprotective properties, and produces various phenolic compounds including flavonoids. The present study afforded determination of total phenolic and flavonoid contents, and for the first time, the isolation and characterization of highly oxygenated flavonoids, e.g., 3,3' ,5,6,7,8-hexamethoxy- 4...

  16. The development of isomerization catalysts for production of high-octane products

    Energy Technology Data Exchange (ETDEWEB)

    Pedrosa, A.M. Garrido; Melo, D.M.A.; Araujo, A.S. [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil). Dept. de Quimica; Souza, M.J.B.; Silva, A.O.S. [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil). Dept. de Engenharia Quimica

    2004-07-01

    In current petroleum industry, paraffins larger than C5 are used for catalytic reform. The catalytic reform is one of the most important processes for petroleum refine in reason of all reactions they drive to production of high-octane products. Reformate has high-octane products, but they contain 60% aromatics. Isomerization of C5- C7 can improve the octane number. The octane number of n-heptane is zero and increases after isomerization. For tri branched C7, the octane number reaches 113, which is higher than that of benzene. So, isomerization of C5-C7 is suggested to be a reasonable way to replace or partly replace the catalytic reforming process. It can decrease aromatics content with enhancement of octane number. Liquid acid catalysts were widely used in chemical industry in past decades. However, they face strong environmental challenges. The heavy corrosion of the reactor system is one of the main problems. Thus, solid acid catalysts are investigated for the isomerization reactions. The aim of this work is to develop a catalysts for the production of reformate products. Isomerization is catalyzed by metal-acid bifunctional catalysts. The metal components aid in hydrogenation, while the support, such as, zirconium, clays or zeolites, is the acidic component. (author)

  17. Dehydrogenation and concurrent isomerization of n-butenes on mixed tin and antimony oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Irvine, E.A.; Taylor, D.

    1978-01-01

    The dehydrogenation and concurrent isomerization of n-butenes on mixed tin and antimony oxide catalysts which had been outgassed at 698/sup 0/K were carried out in the presence of oxygen at 474/sup 0/K, and the initial approximately zero-order rates of 1,3-butadiene formation and rates of isomerization were used as a measure of catalytic activity to construct activity patterns as a function of catalyst composition. A comparison of the patterns with those for the isomerization of 3,3-dimethyl-1-butene and for the selective oxidation of propane on the same catalysts indicated that the dehydrogenation of 1-butene involves a m-allyl intermediate, but isomerization occurs through carbonium ion formation. For the cis- and trans-isomers, both reactions apparently occurred via a common allyl (but not m-allyl) intermediate. Dehydrogenation to butadiene decreased in the order 1-butene > cis-2-butene trans-2-butene and was maximum at 10% antimony for 1-butene and 21% antimony for 2-butene. Isomerization was always slower than dehydrogenation and showed two maEima, at 21 (or 27%) and at 75% antimony.

  18. Cryo-EM structure of isomeric molluscan hemocyanin triggered by viral infection.

    Directory of Open Access Journals (Sweden)

    Hongtao Zhu

    Full Text Available Hemocyanins (Hcs of arthropods and mollusks function not only as oxygen transporters, but also as phenoloxidases (POs. In invertebrates, PO is an important component in the innate immune cascade, where it functions as the initiator of melanin synthesis, a pigment involved in encapsulating and killing of pathogenic microbes. Although structures of Hc from several species of invertebrates have been reported, the structural basis for how PO activity is triggered by structural changes of Hc in vivo remains poorly understood. Here, we report a 6.8 Å cryo-electron microscopy (cryo-EM structure of the isomeric form of hemocyanin, which was isolated from Abalone Shriveling syndrome-associated Virus (AbSV infected abalone (Halitotis diversicolor, and build a pseudoatomic model of isomeric H. diversicolor hemocyanin 1 (HdH1. Our results show that, compared with native form of HdH1, the architecture of isomeric HdH1 turns into a more relaxed form. The interactions between certain functional units (FUs present in the native form of Hc either decreased or were totally abolished in the isomeric form of Hc. As a result of that, native state Hc switches to its isomeric form, enabling it to play its role in innate immune responses against invading pathogens.

  19. Naturally occurring flavonoids against human norovirus surrogates.

    Science.gov (United States)

    Su, Xiaowei; D'Souza, Doris H

    2013-06-01

    Naturally occurring plant-derived flavonoids are reported to have antibacterial, antiviral, and pharmacological activities. The objectives of this study were to determine the antiviral effects of four flavonoids (myricetin, L-epicatechin, tangeretin, and naringenin) on the infectivity of food borne norovirus surrogates after 2 h at 37 °C. The lab-culturable surrogates, feline calicivirus (FCV-F9) at titers of ~7 log₁₀ PFU/ml (high titer) or ~5 log₁₀ PFU/ml (low titer) and murine norovirus (MNV-1) at ~5 log₁₀ PFU/ml, were mixed with equal volumes of myricetin, L-epicatechin, tangeretin, or naringenin at concentrations of 0.5 or 1 mM, and incubated for 2 h at 37 °C. Treatments of viruses were neutralized in cell culture medium containing 10 % heat-inactivated fetal bovine serum, serially diluted, and plaque assayed. Each treatment was replicated thrice and assayed in duplicate. FCV-F9 (low titer) was not found to be reduced by tangeretin or naringenin, but was reduced to undetectable levels by myricetin at both concentrations. Low titer FCV-F9 was also decreased by 1.40 log₁₀ PFU/ml with L-epicatechin at 0.5 mM. FCV-F9 at high titers was decreased by 3.17 and 0.72 log₁₀ PFU/ml with myricetin and L-epicatechin at 0.5 mM, and 1.73 log10 PFU/ml with myricetin at 0.25 mM, respectively. However, MNV-1 showed no significant inactivation by the four tested treatments. The antiviral effects of the tested flavonoids are dependent on the virus type, titer, and dose. Further research will focus on understanding the antiviral mechanism of myricetin and L-epicatechin.

  20. High spin states and isomeric decays in doubly-odd 208Fr

    International Nuclear Information System (INIS)

    Kanjilal, D.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R.; Saha, S.; Bhowmik, R.K.; Gehlot, J.; Muralithar, S.; Singh, R.P.; Jnaneswari, G.; Mukherjee, G.; Mukherjee, B.

    2010-01-01

    Neutron deficient isotopes of francium (Z=87, N∼121-123) as excited nuclei were produced in the fusion-evaporation reaction: 197 Au( 16 O, xn) 213-x Fr at 100 MeV. The γ rays from the residues were observed through the high sensitivity Germanium Clover detector array INGA. The decay of the high spin states and the isomeric states of the doubly-odd 208 Fr nuclei, identified from the known sequence of ground state transitions, were observed. The half-lives of the E γ =194(2) keV isomeric transition, known from earlier observations, was measured to be T 1/2 =233(18) ns. A second isomeric transition at E γ =383(2) keV and T 1/2 =33(7) ns was also found. The measured half-lives were compared with the corresponding single particle estimates, based on the level scheme obtained from the experiment.

  1. Structural and spectral comparisons between isomeric benzisothiazole and benzothiazole based aromatic heterocyclic dyes

    Science.gov (United States)

    Wang, Yin-Ge; Wang, Yue-Hua; Tao, Tao; Qian, Hui-Fen; Huang, Wei

    2015-09-01

    A pair of isomeric heterocyclic compounds, namely 3-amino-5-nitro-[2,1]-benzisothiazole and 2-amino-6-nitrobenzothiazole, are used as the diazonium components to couple with two N-substituted 4-aminobenzene derivatives. As a result, two pairs of isomeric aromatic heterocyclic azo dyes have been produced and they are structurally and spectrally characterized and compared including single-crystal structures, electronic spectra, solvatochromism and reversible acid-base discoloration, thermal stability and theoretically calculations. It is concluded that both benzisothiazole and benzothiazole based dyes show planar molecular structures and offset π-π stacking interactions, solvatochromism and reversible acid-base discoloration. Furthermore, benzisothiazole based aromatic heterocyclic dyes exhibit higher thermal stability, larger solvatochromic effects and maximum absorption wavelengths than corresponding benzothiazole based ones, which can be explained successfully by the differences of their calculated isomerization energy, dipole moment and molecular band gaps.

  2. Special features of isomeric ratios in nuclear reactions induced by various projectile particles

    Energy Technology Data Exchange (ETDEWEB)

    Danagulyan, A. S.; Hovhannisyan, G. H., E-mail: hov-gohar@ysu.am; Bakhshiyan, T. M.; Martirosyan, G. V. [Yerevan State University (Armenia)

    2016-05-15

    Calculations for (p, n) and (α, p3n) reactions were performed with the aid of the TALYS-1.4 code. Reactions in which the mass numbers of target and product nuclei were identical were examined in the range of A = 44–124. Excitation functions were obtained for product nuclei in ground and isomeric states, and isomeric ratios were calculated. The calculated data reflect well the dependence of the isomeric ratios on the projectile type. A comparison of the calculated and experimental data reveals, that, for some nuclei in a high-spin state, the calculated data fall greatly short of their experimental counterparts. These discrepancies may be due to the presence of high-spin yrast states and rotational bands in these nuclei. Calculations involving various level-density models included in the TALYS-1.4 code with allowance for the enhancement of collective effects do not remove the discrepancies in the majority of cases.

  3. Possible evidence for shape isomeric γ-decay in μ- atoms of 238U

    International Nuclear Information System (INIS)

    Fromm, W.D.; Ortlepp, H.-G.; Polikanov, S.M.; Schmidt, U.; Zorin, G.N.; Arlt, R.; Musiol, G.

    1977-01-01

    A search for the γ-decay of the shape isomer in muonic 238 U excited by radiationless transitions has been performed. Seven delayed transitions in the energy region of 700 to 3200 keV have been observed with a large Ge(Li) detector. Two transitions with Esub(γ)=2215 and 3131 keV have been attributed to the decay of the shape isomeric state into levels in the first well. The isomeric shift of the second minimum Esub(II) approximately 600 keV in the presence of the muon and the decrease of the lifetime of the shape isomer to tau=12+-2 ns give arguments in favour of the connection of shape isomerism with large quadrupole deformations. (Auth.)

  4. High-spin μs isomeric states in 96 Ag

    International Nuclear Information System (INIS)

    Becerril, A. D.; Lorusso, G.; Amthor, A. M.; Brown, B. A.; Estrade, A.; Guess, C. J.; Hitt, G. W.; Meharchand, R.; Schatz, H.; Smith, K.; Zegers, R. G. T.; Baumann, T.; Bazin, D.; Ginter, T.; Hausmann, M.; Minamisono, K.; Portillo, M.; Stolz, A.; Berryman, J. S.; Crawford, H. L.

    2011-01-01

    The isomeric and β decays of the N=Z+2 nucleus 96 Ag were investigated at the National Superconducting Cyclotron Laboratory. A cascade of γ-ray transitions originating from the deexcitation of a microsecond isomer was observed for the first time and was found in coincidence with two previously known transitions with energies of 470 and 667 keV. The isomeric half-life was determined as 1.45(7) μs, more precise than previously reported. The existence of a second, longer-lived microsecond isomer, associated with a 743-keV γ transition, is also proposed here. Shell model results within the (p 3/2 p 1/2 f 5/2 g 9/2 ) model space, using the jj44b interaction, reproduced level energies and isomeric decay half-lives reasonably well.

  5. Synthesis, structure and isomerism of three-bridge exo-nido-osmacarborane clusters

    International Nuclear Information System (INIS)

    Kolomnikova, G.D.; Petrovskij, P.V.; Sorokin, P.V.; Dolgushin, F.M.; Yanovskij, A.I.; Chizhevskij, I.T.

    2001-01-01

    The structure and isomerism of exo-nido-osmacarboranes prepared by reaction between coordination-unsaturated complex OsCl 2 (PPh 3 ) 3 (Ph-phenyl) in benzene at 20 deg C and K + -salts of nido-dicarbaundecarborate anions were studied by the methods of 1 H and 11 B NMR (including usual and two-dimensional spectra) and X-ray diffraction analysis. It was ascertained that in the compounds prepared osmium-containing group is bound with nido-carborane ligand via three-center bonds, open pentagonal plane of carborane ligand being retained in the isomers. In it nature isomerism in the compounds mentioned is geometrical cis-trans-isomerism [ru

  6. Flavonoids from the roots of Artocarpus heterophyllus.

    Science.gov (United States)

    Yuan, Wen-Jun; Yuan, Jin-Bin; Peng, Jia-Bing; Ding, Yuan-Qing; Zhu, Ji-Xiao; Ren, Gang

    2017-03-01

    Four new flavonoids, artoheteroids A-D (1-4), together with six known ones (5-10), were isolated from the roots of Artocarpus heterophyllus. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR, UV, IR, CD, and HR-ESI-MS. All isolated compounds were screened for their inhibitory abilities against cathepsin K (CatK). Among them, compounds 1-2, 4-6, and 10 were found to have suppression capabilities against CatK with IC 50 values ranging from 1.4 to 93.9μM. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Flavonoids and sesquiterpenes of Croton pedicellatus Kunth

    International Nuclear Information System (INIS)

    Lopes, Elton Luz; Andrade Neto, Manoel; Silveira, Edilberto Rocha; Pessoa, Otilia Deusdenia Loiola; Braz-Filho, Raimundo

    2012-01-01

    The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6 - O-p-coumaroyl-β-galactopyranosyl- kaempferol, 6 - O-p-coumaroyl-β-glucopyranosyl-3 - methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric methods, including HR-ESI-MS, 1D and 2D NMR experiments, and by comparison with previously-described physical and spectral data. (author)

  8. Flavonoides e sesquiterpenos de Croton pedicellatus Kunth

    Directory of Open Access Journals (Sweden)

    Elton Luz Lopes

    2012-01-01

    Full Text Available The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6"-O-p-coumaroyl-β-galactopyranosyl- kaempferol, 6"-O-p-coumaroyl-β-glucopyranosyl-3"-methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric methods, including HR-ESI-MS, 1D and 2D NMR experiments, and by comparison with previously-described physical and spectral data.

  9. Mechanisms of carcinogenesis prevention by flavonoids

    Directory of Open Access Journals (Sweden)

    G. A. Belitsky

    2014-01-01

    Full Text Available The mechanisms of anticancerogenic effects of flavanoids and isocyanates from the plants widely consumed in the midland belt of Russia were reviewed. Data of studies both in vitro and in vivo were analyzed. Special attention was paid to inhibition of targets responsible for carcinogen metabolic activation, carcinogenesis promotion and tumor progression as well as neoangiogenesis. Besides that the antioxidant properties of flavonoids and their effects on cell cycle regulation, apoptosis initiation and cell mobility were considered.

  10. Flavonoid intake and cardiovascular disease mortality in a prospective cohort of US adults

    Science.gov (United States)

    Background: Flavonoids are plant-based phytochemicals with cardiovascular protective properties. Few studies have comprehensively examined flavonoid classes in relation to cardiovascular disease mortality. We examined the association between flavonoid intake and cardiovascular disease (CVD) mortalit...

  11. Glucose isomerization in simulated moving bed reactor by Glucose isomerase

    Directory of Open Access Journals (Sweden)

    Eduardo Alberto Borges da Silva

    2006-05-01

    Full Text Available Studies were carried out on the production of high-fructose syrup by Simulated Moving Bed (SMB technology. A mathematical model and numerical methodology were used to predict the behavior and performance of the simulated moving bed reactors and to verify some important aspects for application of this technology in the isomerization process. The developed algorithm used the strategy that considered equivalences between simulated moving bed reactors and true moving bed reactors. The kinetic parameters of the enzymatic reaction were obtained experimentally using discontinuous reactors by the Lineweaver-Burk technique. Mass transfer effects in the reaction conversion using the immobilized enzyme glucose isomerase were investigated. In the SMB reactive system, the operational variable flow rate of feed stream was evaluated to determine its influence on system performance. Results showed that there were some flow rate values at which greater purities could be obtained.Neste trabalho a tecnologia de Leito Móvel Simulado (LMS reativo é aplicada no processo de isomerização da glicose visando à produção de xarope concentrado de frutose. É apresentada a modelagem matemática e uma metodologia numérica para predizer o comportamento e o desempenho de unidades reativas de leito móvel simulado para verificar alguns aspectos importantes para o emprego desta tecnologia no processo de isomerização. O algoritmo desenvolvido utiliza a abordagem que considera as equivalências entre as unidades reativas de leito móvel simulado e leito móvel verdadeiro. Parâmetros cinéticos da reação enzimática são obtidos experimentalmente usando reatores em batelada pela técnica Lineweaver-Burk. Efeitos da transferência de massa na conversão de reação usando a enzima imobilizada glicose isomerase são verificados. No sistema reativo de LMS, a variável operacional vazão da corrente de alimentação é avaliada para conhecer o efeito de sua influência no

  12. Impacts of daily intakes on the isomeric profiles of perfluoroalkyl substances (PFASs) in human serum.

    Science.gov (United States)

    Shan, Guoqiang; Wang, Zhi; Zhou, Lianqiu; Du, Pin; Luo, Xiaoxiao; Wu, Qiannian; Zhu, Lingyan

    2016-01-01

    Perfluoroalkyl substances (PFASs) have been well studied in human daily intake for assessment of potential health risks. However, little is known about the isomeric compositions of PFASs in daily intake and their impacts on isomeric profiles in humans. In this study, we investigated the occurrence of PFASs with isomeric analysis in various human exposure matrices including foodstuffs, tap water and indoor dust. Perfluorooctanesulfonate (PFOS) and/or perfluorooctanoate (PFOA) were predominant in these exposure matrices collected in Tianjin, China. In fish and meat, linear (n-) PFOA was enriched with a percentage of 92.2% and 99.6%, respectively. Although n-PFOS was higher in fish (84.8%) than in technical PFOS (ca. 70%), it was much lower in meat (63.1%) and vegetables (58.5%). Dietary intake contributed >99% of the estimated daily intake (EDI) for the general population. The isomeric profiles of PFOA and PFOS in human serum were predicted based on the EDI and a one-compartment, first-order pharmacokinetic model. The isomeric percentage of n-PFOA in the EDI (98.6%) was similar to that in human serum (predicted: 98.2%, previously measured: 99.7%) of Tianjin residents. The results suggest direct PFOA intake plays an important role in its isomeric compositions in humans. For PFOS, the predicted n-PFOS (69.3%) was much higher than the previously measured values (59.2%) in human serum. This implies that other factors, such as indirect exposure to PFOS precursors and multiple excretion pathways, may contribute to the lower percentage of n-PFOS in humans than of technical PFOS. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. NaSO2Ph Induced Exclusive Isomerization of 1,2-Allenyl Sulfoxides to 2-Alkynylic Phenyl Sulfoxides

    Institute of Scientific and Technical Information of China (English)

    傅春玲; 麻生明

    2005-01-01

    The clean isomerization of 1,2-allenyl sulfoxides in the presence of NaSO2Ph afforded 2-alkynylic phenyl sulfoxides in good yields and selectivities. Although strong base-catalyzed isomerization of allenes to alkynes is known, the mechanism for the current reaction is interesting for the obvious reason that NaSOEPh is a weak base.

  14. Consequences of acid strength for isomerization and elimination catalysis on solid acids.

    Science.gov (United States)

    Macht, Josef; Carr, Robert T; Iglesia, Enrique

    2009-05-13

    We address here the manner in which acid catalysis senses the strength of solid acids. Acid strengths for Keggin polyoxometalate (POM) clusters and zeolites, chosen because of their accurately known structures, are described rigorously by their deprotonation energies (DPE). Mechanistic interpretations of the measured dynamics of alkane isomerization and alkanol dehydration are used to obtain rate and equilibrium constants and energies for intermediates and transition states and to relate them to acid strength. n-Hexane isomerization rates were limited by isomerization of alkoxide intermediates on bifunctional metal-acid mixtures designed to maintain alkane-alkene equilibrium. Isomerization rate constants were normalized by the number of accessible protons, measured by titration with 2,6-di-tert-butylpyridine during catalysis. Equilibrium constants for alkoxides formed by protonation of n-hexene increased slightly with deprotonation energies (DPE), while isomerization rate constants decreased and activation barriers increased with increasing DPE, as also shown for alkanol dehydration reactions. These trends are consistent with thermochemical analyses of the transition states involved in isomerization and elimination steps. For all reactions, barriers increased by less than the concomitant increase in DPE upon changes in composition, because electrostatic stabilization of ion-pairs at the relevant transition states becomes more effective for weaker acids, as a result of their higher charge density at the anionic conjugate base. Alkoxide isomerization barriers were more sensitive to DPE than for elimination from H-bonded alkanols, the step that limits 2-butanol and 1-butanol dehydration rates; the latter two reactions showed similar DPE sensitivities, despite significant differences in their rates and activation barriers, indicating that slower reactions are not necessarily more sensitive to acid strength, but instead reflect the involvement of more unstable organic

  15. Excitation of isomeric states 1h11/2 in (γ, n) reactions

    International Nuclear Information System (INIS)

    Tonchev, A.P.; Gangrskij, Yu.P.; Belov, A.G.

    1995-01-01

    The cross sections of (γ, n) reactions were measured for ground and isomeric states 1h 11/2 in 16 isotopes of Pd, Cd, Sn, Te, Ba, Ce, Nd and Sm. The energy of γ-rays was placed in the region of Giant Dipole Resonance. An activation method of measurements has been used. IR dependence of neutron and proton number in nucleus was detected and of excitation energy of residual nucleus as well. Different factors influencing the values of the isomeric ratios are discussed. 20 refs., 5 figs., 2 tabs

  16. Isomeric ratio measurements for the radiative neutron capture 176Lu(n,γ at DANCE

    Directory of Open Access Journals (Sweden)

    Denis-Petit D.

    2017-01-01

    Full Text Available The isomeric ratios for the neutron capture reaction 176Lu(n,γ to the Jπ = 5/2−, 761.7 keV, T1/2 = 32.8 ns and the Jπ = 15/2+, 1356.9 keV, T1/2 = 11.1 ns levels of 177Lu, have been measured for the first time with the Detector for Advanced Neutron Capture Experiments (DANCE at the Los Alamos National Laboratory. These measured isomeric ratios are compared with TALYS calculations.

  17. Tin-containing zeolites are highly active catalysts for the isomerization of glucose in water

    OpenAIRE

    Moliner, Manuel; Román-Leshkov, Yuriy; Davis, Mark E.

    2010-01-01

    The isomerization of glucose into fructose is a large-scale reaction for the production of high-fructose corn syrup (HFCS; reaction performed by enzyme catalysts) and recently is being considered as an intermediate step in the possible route of biomass to fuels and chemicals. Here, it is shown that a large-pore zeolite that contains tin (Sn-Beta) is able to isomerize glucose to fructose in aqueous media with high activity and selectivity. Specifically, a 10% (wt/wt) glucose solution containin...

  18. Kinetic and mass transfer studies on the isomerization of cellulose hydrolyzate using immobilized Streptomyces cells

    Energy Technology Data Exchange (ETDEWEB)

    Ghose, T K; Chand, S

    1978-01-01

    Streptomyces cells possessing glucose isomerase activity, heat-treated and confined within polyester sacs have been used in batch/continuous isomerization of enzymatically hydrolyzed microcrystalline cellulose. Conversion data at different concentrations of substrate closely follow the reactor performance equation based on the reaction kinetics. The effect of external film and pore diffusional resistances were experimentally found to be negligible. The dispersion effects in the packed bed column have been evaluated by pulse input tracer analysis. Continuous operation of the column to isomerize cellulose hydrolyzate (2.0 M glucose) showed an exponential deactivation of enzyme activity with a half-life of 447 h.

  19. Efficient Isomerization of Glucose to Fructose over Zeolites in Consecutive Reactions in Alcohol and Aqueous Media

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Paniagua, Marta; Melero, Juan A

    2013-01-01

    glucose isomerization to fructose and subsequent reaction with methanol to form methyl fructoside (step 1), followed by hydrolysis to re-form fructose after water addition (step 2). NMR analysis with (13)C-labeled sugars confirmed this reaction pathway. Conversion of glucose for 1 h at 120 °C with H......-USY (Si/Al = 6) gave a remarkable 55% yield of fructose after the second reaction step. A main advantage of applying alcohol media and a catalyst that combines Brønsted and Lewis acid sites is that glucose is isomerized to fructose at low temperatures, while direct conversion to industrially important...

  20. High-pressure liquid chromatographic determination of chlorphenesin carbamate and the beta-isomeric carbamate.

    Science.gov (United States)

    Beyer, W F

    1976-12-01

    A high-pressure liquid chromatographic assay was developed for the determination of chlorphenesin carbamate and its beta-isomeric carbamate. A single 4-mm i.d. X 30-cm column, prepacked with 10 micrometer fully porous silica gel particles, is used with 3% methanol in 50% water-saturated butyl chloride as the mobile phase. The procedure separates chlorphenesin carbamate from several possible impurities in addition to the beta-isomeric carbamate. The assay was applied to bulk drug and compressed tablets. The relative standard deviations for the assays of chlorphenesin carbamate and the beta-isomer are approximately 1 and 2%, respectively.

  1. Preparing isomerically pure beams of short-lived nuclei at JYFLTRAP

    Energy Technology Data Exchange (ETDEWEB)

    Eronen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 (Finland)], E-mail: tommi.eronen@jyu.fi; Elomaa, V.-V.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Rahaman, S.; Rissanen, J.; Weber, C.; Aystoe, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FIN-40014 (Finland)

    2008-10-15

    A new procedure to prepare isomerically clean samples of short-lived ions with a mass resolving power of more than 1 x 10{sup 5} has been developed at the JYFLTRAP tandem Penning trap system. The method utilises a dipolar rf-excitation of the ion motion with separated oscillatory fields in the precision trap. During a subsequent retransfer to the purification trap, the contaminants are rejected and as a consequence, the remaining bunch is isomerically cleaned. This newly-developed method is suitable for very high-resolution cleaning and is at least a factor of five faster than the methods used so far in Penning trap mass spectrometry.

  2. Determination of the active site and mechanism for alkene isomerization in Cu(II) exchnaged Y-type zeolite

    Energy Technology Data Exchange (ETDEWEB)

    John, C S; Leach, H F

    1977-01-01

    An ESR study of 1-butene isomerization at 315/sup 0/-375/sup 0/C, 3,3-dimethyl-1-butene isomerization to 2,3-dimethyl-1- and -2-butene at 293/sup 0/K, and deuterium redistribution in 3,3-dideuteriopropene at 363/sup 0/-396/sup 0/K showed the presence of two copper(II) species in different environments, which reacted with the olefins at different rates. Although activation energies for the three reactions differed and only dideuteriopropene showed an induction period, a similar mechanism is proposed in all cases, involving preliminary reduction of copper(II), with the rates of reduction and isomerization differing from olefin to olefin. Apparently, the active site for the isomerization is a Broensted acid generated by the reduction, and the isomerization follows an associative (proton addition-elimination) mechanism with a carbonium ion intermediate. Spectra, graphs, diagram, and 12 references.

  3. Gastroprotective effects of flavonoids in plant extracts.

    Science.gov (United States)

    Zayachkivska, O S; Konturek, S J; Drozdowicz, D; Konturek, P C; Brzozowski, T; Ghegotsky, M R

    2005-03-01

    The purpose of this paper is to overview the relations between plant-originated substances and their bioactivity measured in terms of antioxidant, cytoprotective and antiulcer activities. In addition, we assessed whether these compounds are capable of affecting the gastric mucosal lesions induced by absolute ethanol applied intragastrically (i.g.). The following plant-originated flavonoid substances were considered; Solon (Sophoradin extract), Amaranth seed extract, grapefruit-seed extract (GSE) and capsaicin (extract of chilly pepper). The area of gastric mucosa lesions and gastric blood flow were measured in rats with ethanol-induced lesions without (control) and with one of the tested substances without and with capsaicin denervation of afferent nerves or administration of L-nitro-arginine (L-NNA), an inhibitor of nitric oxide synthase (NOS). Male Wistar rats, weighing 180-220 g fasted for 24 h before the study where used 100% ethanol was applied i.g. to induce gastric lesions, whose area was determined by planimetry. Gastric blood flow was assessed using electrolytic regional blood flowmeter. All tested plant-originated substances afforded gastroprotection against ethanol-induced damage and this was accompanied by increase in gastric microcirculation, both changes being reversed by pretreatment with neurotoxic dose of capsaicin or by pretreatment with L-NNA. We conclude that plant-originated flavonoid substances are highly gastroprotective probably due to enhancement of the expression of constitutive NOS and release of NO and neuropeptides such as calcitonin gene related peptide (CGRP) released from sensory afferent nerves increasing gastric microcirculation.

  4. Cytoprotective effects of dietary flavonoids against cadmium-induced toxicity.

    Science.gov (United States)

    Li, Xia; Jiang, Xinwei; Sun, Jianxia; Zhu, Cuijuan; Li, Xiaoling; Tian, Lingmin; Liu, Liu; Bai, Weibin

    2017-06-01

    Cadmium (Cd) damages the liver, kidney, bones, reproductive system, and other organs. Flavonoids, such as anthocyanins and flavonols, which are commonly found in plant foods, have shown protective effects against Cd-induced damage. The cytoprotective effects of flavonoids against Cd-induced diseases are mainly attributable to three mechanisms. First, flavonoids clear reactive oxygen species, thereby reducing lipid peroxide production and improving the activity of antioxidation enzymes. Second, flavonoids chelate Cd, thus reducing the accumulation of Cd and altering the levels of other essential metal ions in vivo. Third, flavonoids reduce DNA damage and inhibit apoptosis. In addition, flavonoids were found to inhibit inflammation and fibrosis and improve glycometabolism and the secretion of reproductive hormones. We introduce the daily dosage and absorption rate of flavonoids and then focus on their bioactive effects against Cd-induced toxicity and reveal the underlying metabolic pathway, which provides a basis for further study of the nutritional prevention of Cd-induced injury. In particular, a better understanding is needed of the structure-activity relationship of flavonoids against Cd toxicity, which has not yet been reported. © 2017 New York Academy of Sciences.

  5. Antibacterial, anti-inflammatory and diuretic effect of flavonoids from ...

    African Journals Online (AJOL)

    Dried leaves of Marchantia convoluta are largely used to protect livers, and to treat tumefaction of skins in China. Flavonoids from Marchantia convoluta (MCF) were the active components against hepatitis B virus. In this study, the pharmacological properties of MCF consisting of flavonoids determined by HPLC were ...

  6. Dietary supplementation with mulberry leaf flavonoids inhibits methanogenesis in sheep.

    Science.gov (United States)

    Ma, Tao; Chen, Dan-Dan; Tu, Yan; Zhang, Nai-Feng; Si, Bing-Wen; Diao, Qi-Yu

    2017-01-01

    The effects of flavonoids on methanogenesis and microbial flora in Dorper × thin-tailed Han crossbred ewes were evaluated in two experiments. To investigate the effects of flavonoids on nutrient digestibility and nitrogen balance, 18 ewes (60.0 ± 1.73 kg body weight (BW)) were allotted to two dietary treatments in experiment one, a control diet and the control diet supplemented with flavonoids (2 g/head/day). In experiment two, the effects of supplementary flavonoids on ruminal fermentation and microbial flora were investigated using quantitative polymerase chain reaction with six ewes (67.2 ± 0.79 kg BW) with ruminal cannula assigned to the identical dietary treatments used in experiment one. Supplementary flavonoids improved the apparent digestibility of nitrogen (N, P flavonoids, whereas the total volatile fatty acid (VFA) content increased (P = 0.037). Supplementary flavonoids decreased ruminal populations of protozoans (P = 0.002) and methanogens (P flavonoids improved the digestibility of organic matter and reduced CH 4 output by inhibiting the populations of microbes involved in methanogenesis. © 2016 Japanese Society of Animal Science.

  7. Cytotoxic flavonoids from Erythrina caffra Thunb | Y. Desta | Bulletin ...

    African Journals Online (AJOL)

    Erythrina caffra is an important medicinal plant native to South Africa. Its stem bark was investigated for the flavonoid constituents and biological activity. Some isolated flavonoids, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15 and 16 were found to be active against the human cervix carcinoma KB-3-1 cells with IC50 values in the ...

  8. Brosimacutins A-I, nine new flavonoids from Brosimum acutifolium.

    Science.gov (United States)

    Takashima, Junko; Ohsaki, Ayumi

    2002-12-01

    Nine new flavonoids, brosimacutins A-I (1-9), and four known flavonoids were isolated from the bark of Brosimum acutifolium, a Brazilian folk medicine ("Mururé"). Their structures were elucidated by spectroscopic methods, including 2D NMR. Brosimacutins A-I possess differentially functionalized isoprene units at C-8.

  9. Efficacy of Food Proteins as Carriers for Flavonoids

    NARCIS (Netherlands)

    Bohin, M.C.; Vincken, J.P.; Hijden, H.T.W.M.; Gruppen, H.

    2012-01-01

    Enrichment of flavonoids in food is often limited by their off-tastes, which might be counteracted by the use of food proteins as carriers of flavonoids. Various milk proteins, egg proteins, and gelatin hydrolysates were compared for their binding characteristics to two flavan-3-ols. Among the

  10. Automated Annotation of Microbial and Human Flavonoid-Derived Metabolites

    NARCIS (Netherlands)

    Mihaleva, V.V.; Ünlü, F.; Vervoort, J.J.M.; Ridder, L.O.

    2015-01-01

    Flavonoids are a class of natural compounds essentially produced by plants that are part of animal and human diets and have assumed health-promoting benefits. Upon human consumption, these flavonoids are to a modest extent absorbed in the small intestines. The major part arrives in the colon where

  11. Metabolic engineering of yeast for fermentative production of flavonoids

    DEFF Research Database (Denmark)

    Rodriguez Prado, Edith Angelica; Strucko, Tomas; Stahlhut, Steen Gustav

    2017-01-01

    Yeast Saccharomyces cerevisiae was engineered for de novo production of six different flavonoids (naringenin, liquiritigenin, kaempferol, resokaempferol, quercetin, and fisetin) directly from glucose, without supplementation of expensive intermediates. This required reconstruction of long...... demonstrates the potential of flavonoid-producing yeast cell factories....

  12. Antimicrobial potential of alkaloids and flavonoids extracted from ...

    African Journals Online (AJOL)

    Background: Alkaloids and flavonoids are secondary metabolites extracted from different medicinal plants. Tamarix aphylla a traditionally valuable medicinal plant; was used for the extraction of alkaloids and flavonoids in order to evaluate their antibacterial activity. Methodology: The leaves of the plant were collected from ...

  13. Ultrasonic-Assisted Extraction and Antioxidant Activity of Flavonoids ...

    African Journals Online (AJOL)

    Purpose: To identify the main flavonoid in Adinandra nitida leaf, employ response surface methodology to optimize its ultrasonic-assisted extraction, and determine the antioxidant activity of the obtained extract. Methods: The main flavonoid in Adinandra nitida leaf was obtained by traditional solvent extraction and ...

  14. FLAVONOID NATURAL SOURCES AND THEIR IMPORTANCE IN THE HUMAN DIET

    Directory of Open Access Journals (Sweden)

    Martina Danihelová

    2011-12-01

    Full Text Available Flavonoids as natural bioactive compounds are present in almost every sort of fruits, vegetables and from them derived products. Flavonols may be found mainly in fruits and vegetables, while flavones are abundant in herbs and spices. Rich natural sources of flavanols are tea, cocoa, grape seeds or apple skin. Flavanones are primarily found in a variety of citrus fruits and anthocyanidins in many coloured berries. Soy is rich in isoflavonoids. Average daily intake of flavonoids is approximately in the range of 150 to 300 mg. It strongly depends on individual, country and culture usages. In west countries main dietary sources of flavonoids consist of tea, wine and fruits, while in east countries there is consumed mainly soy with high isoflavonoid content. Many studies have shown, that intake of fruits and vegetables with high flavonoid content is associated with lowered risk of incidence of some diseases such as cardiovascular or cancer. These findings are attributed to experimentally confirmed biological effects of flavonoids - antioxidant, anti-inflammatory, anti-allergic, anticancer or cardioprotective. The final effect is however depending on their bioavailability, which is in the case of flavonoids not high, because in the nature dominating flavonoid glycosides can poorly penetrate through lipophilic cell membranes. Final effective molecules are flavonoid metabolites, that more or less retain their biological activities. doi: 10.5219/160

  15. Flavonoids patterns of French honeys with different floral origin

    NARCIS (Netherlands)

    Soler, C.; Gil, M.I.; Garcia-Viguera, C.; Tomás-Barberán, F.A.

    1995-01-01

    The flavonoid profiles of 12 different unifloral French honey samples were analysed by HPLC to evaluate if these substances could be used as markers of the floral origin of honey. In this analysis, the characteristic flavonoids from propolis and/or beeswax (chrysin, galangin, tectochrysin,

  16. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    Science.gov (United States)

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  17. Extraction and Purification of Flavonoids from Radix Puerariae

    African Journals Online (AJOL)

    content of puerarin and flavonoids in the samples were tested by a HPLC and a UV-Vis. Spectrophotometer, respectively. ... the weight of the crude drug), the volume of loading sample is 2 BV (bed volume). The mobile phases of desorption are ... flavonoids, they have a variety of biological activities [1-3] including improving ...

  18. Quantification and antibacterial activity of flavonoids in coffee samples

    African Journals Online (AJOL)

    Background: Flavonoids are the phenolic substances widely found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and coffee. Methodology: In the current study quantity of flavonoids and antibacterial activities were determined in different coffee samples namely Nescafe classic, Nescafe gold, Nescafe martina, ...

  19. The therapeutic potential of plant flavonoids on rheumatoid arthritis.

    Science.gov (United States)

    Hughes, Samuel D; Ketheesan, Natkunam; Haleagrahara, Nagaraja

    2017-11-22

    Rheumatoid arthritis (RA) is an autoimmune condition that mainly affects peripheral joints. Although immunosuppressive drugs and non-steroidal anti-inflammatory drugs (NSAIDs) are used to treat this condition, these drugs have severe side effects. Flavonoids are the most abundant phenolic compounds which exhibit anti-oxidant, anti-inflammatory and immunomodulatory properties. Many bioactive flavonoids have powerful anti-inflammatory effects. However, a very few have reached clinical use. Dietary flavonoids have been reported to control joint inflammation and alleviate arthritis symptoms in both human RA and animal models of arthritis. There is little scientific evidence about their mechanism of actions in RA. We review the therapeutic effects of different groups of flavonoids belonging to the most common and abundant groups on RA. In particular, the probable mechanisms of major flavonoids on cells and chemical messengers involved in the inflammatory signaling components of RA are discussed in detail.

  20. Flavonoids in the development of functional meat products: A review

    Directory of Open Access Journals (Sweden)

    Pramod K. Singh

    2013-06-01

    Full Text Available Flavonoids or bioflavonoids are unique low molecular weight ubiquitous polyphenolic compounds produced by plants during their metabolic activities as a secondary metabolites and responsible for major organoleptic characteristics and health benefits of plant derived foods. The flavonoids are potent antioxidants agents and protect the cells by scavenging and inhibiting the production and initiation of free radicals, superoxide anions and lipid peroxy radicals. Besides potent antioxidant capacity, flavonoids also shows antimicrobial, antimutagenic, antidiabetic, antithrombosis, antirheumatic, antiatherosclerotic, antiallergic, anti-inflammatory, antiulcers and hepatoprotectives and better termed as neutraceuticals. The antioxidant capacity of meat is very low and this can be increased by adding flavonoids in meat during processing in the form of plant parts rich in flavonoids such as seeds, fruit skin or peel, bark and flower as raw or in extract form without comprising the sensory attributes of meat and meat products. [Vet World 2013; 6(8.000: 573-578

  1. The flavonoid biosynthetic pathway in plants: function and evolution

    International Nuclear Information System (INIS)

    Koes, R.E.; Quattrocchio, F.; Mol, J.N.M.

    1994-01-01

    Flavonoids are a class of low molecular weight phenolic compounds that is widely distributed in the plant kingdom. They exhibit a diverse spectrum of biological functions and play an important role in the interaction between plants and their environment. Flavonoids not only protect the plant from the harmful effects of UV irradiation but also play a crucial role in the sexual reproduction process. A special class of flavonoid polymers, the tannins, plays a structural role in the plant. Yet other classes of flavonoids, flavonols and anthocyanins, have been implicated in the attraction of pollinators. Certain flavonoids participate in the interaction between plants and other organisms such as symbiotic bacteria and parasites. This raises the intriguing question as to how these different compounds arose and evolved. Based on taxonomy and molecular analysis of gene expression patterns it is possible to deduce a putative sequence of acquisition of the different branches of the biosynthetic pathway and their regulators. (author)

  2. UV radiation dependent flavonoid accumulation of Cistus laurifolius L

    International Nuclear Information System (INIS)

    Vogt, T.; Gülz, P.-G.; Reznik, H.

    1991-01-01

    Epicuticular and intracellular flavonoids of Cistus laurifolius grown with and without UV radiation in a phytotron as well as under natural garden conditions in the field were studied. The amount of intracellular flavonoid glycosides of leaves receiving UV-A radiation was two fold higher than that measured in the absence o f UV-A radiation, whether grown in the phytotron or in the field. Exposure of previously protected leaves to UV-A radiation increased the intracellular flavonoid glycoside content to that of unprotected leaves. The qualitative composition of intracellular flavonoid glycosides showed a reduced amount of quercetin-3-galactoside to the myricetin monosides when the leaves were grown without UV-A radiation in the field and in the phytotron. Epicuticular flavonoid aglycones were not influenced by UV radiation significantly. (author)

  3. Floral flavonoids and ultraviolet patterns in Viguiera (Compositae)

    International Nuclear Information System (INIS)

    Rieseberg, L.H.; Schilling, E.E.

    1985-01-01

    Variation occurs among species of Viguiera series Viguiera for ultraviolet (UV) absorption/reflection patterns of ligules. Floral flavonoids that cause UV absorption occur in epidermal papillae. Flavonoids are further localized to the proximal portion of the ligule in the seven taxa that have only proximal UV absorption. Floral flavonoids involved in UV absorption consist of flavone, flavonol, and anthochlor (chalcone/aurone) glycosides. Quercetin 3-methyl ether glycosides characterize the ligules of 10 taxa occurring in Baja California, Mexico, and nearby areas, and these taxa appear to form one taxonomic group. The anthochlor pair, marein/maritimein, characterizes V. dentata, and the lack of ligule flavonoids distinguishes V. potosina from the remaining taxa. The presence of the anthochlor pair, marein/maritimein, only in V. dentata and the lack of ligule flavonoids in V. potosina concur with other data to indicate that these species are not correctly placed with each other or with the other species currently included in series Viguiera. (author)

  4. The flavonoid biosynthetic pathway in plants: function and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Koes, R. E.; Quattrocchio, F.; Mol, J. N.M. [Department of Genetics, Institute for Molecular Biological Sciences, Vrije Universiteit, BioCentrum Amsterdam, De Boelelaan 1087, 1081HV, Amsterdam (Netherlands)

    1994-07-01

    Flavonoids are a class of low molecular weight phenolic compounds that is widely distributed in the plant kingdom. They exhibit a diverse spectrum of biological functions and play an important role in the interaction between plants and their environment. Flavonoids not only protect the plant from the harmful effects of UV irradiation but also play a crucial role in the sexual reproduction process. A special class of flavonoid polymers, the tannins, plays a structural role in the plant. Yet other classes of flavonoids, flavonols and anthocyanins, have been implicated in the attraction of pollinators. Certain flavonoids participate in the interaction between plants and other organisms such as symbiotic bacteria and parasites. This raises the intriguing question as to how these different compounds arose and evolved. Based on taxonomy and molecular analysis of gene expression patterns it is possible to deduce a putative sequence of acquisition of the different branches of the biosynthetic pathway and their regulators. (author)

  5. A fluorescence quenching test for the detection of flavonoid transformation.

    Science.gov (United States)

    Schoefer, L; Braune, A; Blaut, M

    2001-11-13

    A novel fluorescence quenching test for the detection of flavonoid degradation by microorganisms was developed. The test is based on the ability of the flavonoids to quench the fluorescence of 1,6-diphenyl-1,3,5-hexatriene (DPH). Several members of the anthocyanidins, flavones, isoflavones, flavonols, flavanones, dihydroflavanones, chalcones, dihydrochalcones and catechins were tested with regard to their quenching properties. The anthocyanidins were the most potent quenchers of DPH fluorescence, while the flavanones, dihydroflavanones and dihydrochalcones, quenched the fluorescence only weakly. The catechins had no visible impact on DPH fluorescence. The developed test allows a quick and easy differentiation between flavonoid-degrading and flavonoid-non-degrading bacteria. The investigation of individual reactions of flavonoid transformation with the developed test system is also possible.

  6. Extraction, isolation and identification of flavonoid from Euphorbia neriifolia leaves

    Directory of Open Access Journals (Sweden)

    Veena Sharma

    2017-05-01

    Full Text Available The flavonoids contained in Euphorbia neriifolia leaves were extracted, identified and characterized. Direct and sequential soxhlet extraction and its concentrated fractions were subjected to thin layer chromatography and high performance thin layer chromatography. The results showed that maximum yield of the flavonoid (6.53 g was obtained from ethanolic extract. The Rf value of isolated flavonoid and phytochemical screening has been compared with standard Quercetin. Characterization of isolated flavonoid was done by IR, 1H NMR, and MS. On the basis of chemical and spectral analysis structure was elucidated as 2-(3,4-dihydroxy-5-methoxy-phenyl-3,5-dihydroxy-6,7-dimethoxychromen-4-one, a flavonoid. This compound was isolated for the first time from this plant.

  7. Total phenolics and total flavonoids in selected Indian medicinal plants.

    Science.gov (United States)

    Sulaiman, C T; Balachandran, Indira

    2012-05-01

    Plant phenolics and flavonoids have a powerful biological activity, which outlines the necessity of their determination. The phenolics and flavonoids content of 20 medicinal plants were determined in the present investigation. The phenolic content was determined by using Folin-Ciocalteu assay. The total flavonoids were measured spectrophotometrically by using the aluminium chloride colorimetric assay. The results showed that the family Mimosaceae is the richest source of phenolics, (Acacia nilotica: 80.63 mg gallic acid equivalents, Acacia catechu 78.12 mg gallic acid equivalents, Albizia lebbeck 66.23 mg gallic acid equivalents). The highest total flavonoid content was revealed in Senna tora which belongs to the family Caesalpiniaceae. The present study also shows the ratio of flavonoids to the phenolics in each sample for their specificity.

  8. Anticonvulsant effects of isomeric nonimidazole histamine H3 receptor antagonists

    Directory of Open Access Journals (Sweden)

    Sadek B

    2016-11-01

    , in which 3-piperidinopropan-1-ol in ligand 2 was replaced by (4-(3-(piperidin-1-ylpropoxyphenylmethanol, and its (S-enantiomer (4 significantly and in a dose-dependent manner reduced convulsions or exhibited full protection in MES and PTZ convulsions model, respectively. Interestingly, the protective effects observed for the (R-enantiomer (3 in MES model were significantly greater than those of the standard H3R inverse agonist/antagonist pitolisant, comparable with those observed for PHT, and reversed when rats were pretreated with the selective H3R agonist R-(α-methyl-histamine. Comparisons of the observed antagonistic in vitro affinities among the ligands 1–6 revealed profound stereoselectivity at human H3Rs with varying preferences for this receptor subtype. Moreover, the in vivo anticonvulsant effects observed in this study for ligands 1–6 showed stereoselectivity in different convulsion models in male adult rats. Keywords: histamine, H3 receptor, isomeric antagonists, anticonvulsant activity, stereo­selectivity

  9. Elucidation of structural isomers from the homogeneous rhodium-catalyzed isomerization of vegetable oils.

    Science.gov (United States)

    Andjelkovic, Dejan D; Min, Byungrok; Ahn, Dong; Larock, Richard C

    2006-12-13

    The structural isomers formed by the homogeneous rhodium-catalyzed isomerization of several vegetable oils have been elucidated. A detailed study of the isomerization of the model compound methyl linoleate has been performed to correlate the distribution of conjugated isomers, the reaction kinetics, and the mechanism of the reaction. It has been shown that [RhCl(C8H8)2]2 is a highly efficient and selective isomerization catalyst for the production of highly conjugated vegetable oils with a high conjugated linoleic acid (CLA) content, which is highly desirable in the food industry. The combined fraction of the two major CLA isomers [(9Z,11E)-CLA and (10E,12Z)-CLA] in the overall CLA mixture is in the range from 76.2% to 93.4%. The high efficiency and selectivity of this isomerization method along with the straightforward purification process render this approach highly promising for the preparation of conjugated oils and CLA. Proposed improvements in catalyst recovery and reusability will only make this method more appealing to the food, paint, coating, and polymer industries in the future.

  10. Changes in Atmospheric Butanes and Pentanes and Their Isomeric Ratios in the Continental United States

    Science.gov (United States)

    Rossabi, Sam; Helmig, Detlev

    2018-04-01

    Nonmethane hydrocarbons have been used as tracers in research on emissions and atmospheric oxidation chemistry. This research investigates source region mixing ratio trends of the nonmethane hydrocarbons i-butane, n-butane, i-pentane, and n-pentane, and the (i/n) isomeric ratios of these compounds between 2001 and 2015. Data collected at Photochemical Assessment Monitoring Stations, mandated by the U.S. Environmental Protection Agency in ozone nonattainment areas, and data collected at Global Greenhouse Gas Reference Network sites within the National Oceanic and Atmospheric Administration network, and analyzed at the Institute of Arctic and Alpine Research at the University of Colorado-Boulder, were examined. Among all considered species, linear regression analyses on concentration time series had negative slopes at 81% of sites, indicating predominantly declining butane and pentane atmospheric concentrations. Mostly negative slopes (78% of sites) were found for the (i/n) butane and pentane isomeric ratios, including all six and seven statistically significant (i/n) butane and pentane trends, respectively. Over the 15 year investigation period and averaged over all sites, total relative changes were 30 and 45% for the (i/n) ratios of butanes and pentanes, respectively, with a relative increase in the prominence of the n-isomers. Most likely causes include changing isomeric ratios in gasoline sector emissions, and increasing influence of oil and natural gas industry emissions. Changes in concentrations and isomeric ratios depend on proximity of contributing emission sources to measurement sites.

  11. Left atrial isomerism associated with asplenia: prenatal echocardiographic detection of complex congenital cardiac malformations

    NARCIS (Netherlands)

    Stewart, P. A.; Becker, A. E.; Wladimiroff, J. W.; Essed, C. E.

    1984-01-01

    Complex congenital heart disease with suspected isomerism of the atria was diagnosed in two fetuses of 20 and 29 weeks' gestation using two-dimensional and M-mode scanning techniques. The first pregnancy was terminated at 21 weeks' gestation and stillbirth occurred at 31 weeks' gestation in the

  12. Resolution of isomeric new designer stimulants using gas chromatography - Vacuum ultraviolet spectroscopy and theoretical computations

    Czech Academy of Sciences Publication Activity Database

    Škultéty, L'udovít; Fryčák, P.; Qiu, CL.; Smuts, J.; Shear-Laude, L.; Lemr, Karel; Mao, J.X.; Kroll, P.; Schug, K. A.; Szewczak, A.; Vaught, C.; Lurie, I.; Havlíček, Vladimír

    2017-01-01

    Roč. 971, JUNE 8 (2017), s. 55-67 ISSN 0003-2670 R&D Projects: GA MŠk(CZ) LO1509 Institutional support: RVO:61388971 Keywords : Gas phase absorption * Time-dependent density functional theory * Isomeric drugs Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 4.950, year: 2016

  13. Ligand induced structural isomerism in phosphine coordinated gold clusters revealed by ion mobility mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Baker, Erin M.; Laskin, Julia; Johnson, Grant E.

    2017-01-01

    Structural isomerism in ligated gold clusters is revealed using electrospray ionization ion mobility spectrometry mass spectrometry. Phosphine ligated Au8 clusters are shown to adopt more “extended” type structures with increasing exchange of methyldiphenylphosphine (MePPh2) for triphenylphosphine (PPh3). These ligand-dependant structure-property relationships are critical to applications of clusters in catalysis.

  14. Phase space conduits for reaction in multidimensional systems : HCN isomerization in three dimensions

    NARCIS (Netherlands)

    Waalkens, Holger; Burbanks, Andrew; Wiggins, Stephen

    2004-01-01

    The three-dimensional hydrogen cyanide/isocyanide isomerization problem is taken as an example to present a general theory for computing the phase space structures which govern classical reaction dynamics in systems with an arbitrary (finite) number of degrees of freedom. The theory, which is

  15. The Isomerization of (-)-Menthone to (+)-Isomenthone Catalyzed by an Ion-Exchange Resin

    Science.gov (United States)

    Ginzburg, Aurora L.; Baca, Nicholas A.; Hampton, Philip D.

    2014-01-01

    A traditional organic chemistry laboratory experiment involves the acid-catalyzed isomerization of (-)-menthone to (+)-isomenthone. This experiment generates large quantities of organic and aqueous waste, and only allows the final ratio of isomers to be determined. A "green" modification has been developed that replaces the mineral acid…

  16. The isomerization of allylrhodium intermediates in the rhodium-catalyzed nucleophilic allylation of cyclic imines.

    Science.gov (United States)

    Hepburn, Hamish B; Lam, Hon Wai

    2014-10-20

    Allylrhodium species generated from potassium allyltrifluoroborates can undergo isomerization by 1,4-rhodium(I) migration to give more complex isomers, which then react with cyclic imines to provide products with up to three new stereochemical elements. High enantioselectivities are obtained using chiral diene-rhodium complexes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Promotion or suppression of glucose isomerization in subcritical aqueous straight- and branched-chain alcohols.

    Science.gov (United States)

    Gao, Da-Ming; Kobayashi, Takashi; Adachi, Shuji

    2015-01-01

    The influence of water-miscible alcohols (methanol, 1-propanol, 2-propanol, and t-butyl alcohol) on the isomerization of glucose to fructose and mannose was investigated under subcritical aqueous conditions (180-200 °C). Primary and secondary alcohols promoted the conversion and isomerization of glucose to afford fructose and mannose with high and low selectivity, respectively. On the other hand, the decomposition (side-reaction) of glucose was suppressed in the presence of the primary and secondary alcohols compared with that in subcritical water. The yield of fructose increased with increasing concentration of the primary and secondary alcohols, and the species of the primary and secondary alcohols tested had little effect on the isomerization behavior of glucose. In contrast, the isomerization of glucose was suppressed in subcritical aqueous t-butyl alcohol. Both the conversion of glucose and the yield of fructose decreased with increasing concentration of t-butyl alcohol. In addition, mannose was not detected in reactions using subcritical aqueous t-butyl alcohol.

  18. Linkage isomerism in trimeric and polymeric 2,3-cis-procyanindins

    Science.gov (United States)

    Richard W. Hemingway; Lai Yeap Foo; Lawrence J. Porter

    1982-01-01

    Procyanindins polymers consist of chains of 5,7,3',4'-tetrahydroxyflavan-3-ol units linked by C(4)-C(6) or C(4)-C(8) bonds.1 Whereas the procyanidin-B group of dimers are known to exist as pairs of isomers with common flavan-3-ol units, but different interflavanoid linkages,2,3 the extent of such isomerism in...

  19. Polymeric proanthocyanidins: Interflavanoid linkage isomerism in (epicatechin-4)-(epicatechin-4)-catechin procyanidins

    Science.gov (United States)

    Richard W. Hemingway; L. Yeap Foo; L. J. Porter

    1981-01-01

    Procyanidin trimers have been isolated from a variety of plants,1-3 but their structures remain unresolved. We have now isolated three configurational isomers of (epicatechin-4)-(epicatechin-4)-catechin from Pinus taeda L. (loblolly pine) phloem which exhibit isomerism of the interflavanoid linkages.

  20. Palladium Hydride Promoted Stereoselective Isomerization of Unactivated Di(exo)methylenes to Endocyclic Dienes

    OpenAIRE

    Jung, Michael E.; Lee, Gloria S.; Pham, Hung V.; Houk, K. N.

    2014-01-01

    The exomethylenes of 2,6-disubstituted bicyclo[3.3.1]nonan-9-ones 2 are readily isomerized over a palladium catalyst under an atmosphere of hydrogen to predominantly form the isomer 3 with C 2 symmetry with very little formation of the analogous product with C s symmetry. A hydrogen source is essential to effect the rearrangement.

  1. Isomeric Diruthenium Complexes Bridged by Deprotonated Indigo in cis and trans Configuration

    Czech Academy of Sciences Publication Activity Database

    Chatterjee, M.; Ghosh, P.; Beyer, K.; Paretzki, A.; Fiedler, Jan; Kaim, W.; Lahiri, G. K.

    2018-01-01

    Roč. 13, č. 1 (2018), s. 118-125 ISSN 1861-4728 Institutional support: RVO:61388955 Keywords : isomerism * ruthenium * spectroelectrochemistry * structure Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.083, year: 2016

  2. Photochromic ruthenium sulfoxide complexes: evidence for isomerization through a conical intersection.

    Science.gov (United States)

    McClure, Beth Anne; Mockus, Nicholas V; Butcher, Dennis P; Lutterman, Daniel A; Turro, Claudia; Petersen, Jeffrey L; Rack, Jeffrey J

    2009-09-07

    The complexes [Ru(bpy)(2)(OS)](PF(6)) and [Ru(bpy)(2)(OSO)](PF(6)), where bpy is 2,2'-bipyridine, OS is 2-methylthiobenzoate, and OSO is 2-methylsulfinylbenzoate, have been studied. The electrochemical and photochemical reactivity of [Ru(bpy)(2)(OSO)](+) is consistent with an isomerization of the bound sulfoxide from S-bonded (S-) to O-bonded (O-) following irradiation or electrochemical oxidation. Charge transfer excitation of [Ru(bpy)(2)(OSO)](+) in MeOH results in the appearance of two new metal-to-ligand charge transfer (MLCT) maxima at 355 and 496 nm, while the peak at 396 nm diminishes in intensity. The isomerization is reversible at room temperature in alcohol or propylene carbonate solution. In the absence of light, solutions of O-[Ru(bpy)(2)(OSO)](+) revert to S-[Ru(bpy)(2)(OSO)](+). Kinetic analysis reveals a biexponential decay with rate constants of 5.66(3) x 10(-4) s(-1) and 3.1(1) x 10(-5) s(-1). Cyclic voltammograms of S-[Ru(bpy)(2)(OSO)](+) are consistent with electron-transfer-triggered isomerization of the sulfoxide. Analysis of these voltammograms reveal E(S)(o)' = 0.86 V and E(O)(o)' = 0.49 V versus Ag/Ag(+) for the S- and O-bonded Ru(3+/2+) couples, respectively, in propylene carbonate. We found k(S-->O) = 0.090(15) s(-1) in propylene carbonate and k(S-->O) = 0.11(3) s(-1) in acetonitrile on Ru(III), which is considerably slower than has been reported for other sulfoxide isomerizations on ruthenium polypyridyl complexes following oxidation. The photoisomerization quantum yield (Phi(S-->O) = 0.45, methanol) is quite large, indicating a rapid excited state isomerization rate constant. The kinetic trace at 500 nm is monoexponential with tau = 150 ps, which is assigned to the excited S-->O isomerization rate. There is no spectroscopic or kinetic evidence for an O-bonded (3)MLCT excited state in the spectral evolution of S-[Ru(bpy)(2)(OSO)](+) to O-[Ru(bpy)(2)(OSO)](+). Thus, isomerization occurs nonadiabatically from an S-bonded (or eta(2

  3. Prenylated flavonoids from maclura tinctoria fruits

    International Nuclear Information System (INIS)

    Oyama, Sayuri de Oliveira; Souza, Luiz Antonio de; Baldoqui, Debora Cristina; Sarragiotto, Maria Helena; Silva, Adriano Antônio

    2013-01-01

    A phytochemical investigation of Maclura tinctoria fruits yielded five flavonoids, including one prenylated flavonol (licoflavonol) and four prenylated isoflavones (wighteone, derrone, alpinum isoflavone, and 6-(2,2-dimethyl-2H-chromen-6-yl)-2-(1-hydroxy-1-methylethyl) -2,3-dihydro-5H-furo[3,2-g]chromen-5-one). The structures of the isolates were established by analyzing their spectroscopic data. Compound 6-(2,2-dimethyl-2H-chromen-6-yl) -2-(1-hydroxy-1-methylethyl)-2,3-ihydro-5H-furo[3,2-g]chromen-5-one is new and the other isolates are described for the first time in this species. (author)

  4. [Studies on the flavonoids from Dendranthema lavandulifolium].

    Science.gov (United States)

    Shen, Y X; Quan, L H; Guan, L; Chen, J M

    1997-06-01

    From the whole plant of Dendranthema lavandulifolium, two flavonoides (I, II) and two flavone glycosides (III, IV) were isolated. They were identified as luteolin (I), apigenin (II), 5-hydroxy-4'-methoxy-flavone-7-O-alpha-L-rhamnopyranosyl(1-->6)-beta- D-glucopyranosyl (acaciin III) and 5-hydroxy-4'-methoxy-flavone-7-O-alpha-L-rhamnopyranosyl (1-->6) [2-O-acetyl-beta-D-glucopyranosyl(1-->2)]-beta-D-glucopyranoside (IV) by means of IR, UV, 1H-NMR, 13C-NMR, EI-MS, HRFAB, etc. Among these four compounds, I, II were isolated for the first time from this plant, IV is a new compound.

  5. Phytotoxic activity of flavonoids from Dicranostyles ampla.

    Science.gov (United States)

    Castro, Amaya; Cantrell, Charles L; Hale, Amber L; Duke, Stephen O

    2010-08-01

    Crude extracts from over 16 species of plants from the family Convolvulaceae were evaluated for phytotoxic activity against Agrostis stolonifera (bentgrass) and Lactuca sativa (lettuce) at 1000 microg/mL. Ethanol extracts of Dicranostyles ampla Ducke were among the most active of those species tested. Systematic bioassay-guided fractionation of the ethanol extract of the aerial parts from this species was performed to identify specifically the phytotoxic compounds. Two phytotoxic flavonoids, dihydromyricetin (1) and myricetin-3-O-alpha-rhamnoside or myricetrin (2), were found to be responsible for much of the activity of the extract as a whole in the A. stolonifera and L. sativa bioassay. In a Lemna paucicostata bioassay, 1 and 2 had no activity at 100 microM.

  6. Prenylated flavonoids from maclura tinctoria fruits

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Sayuri de Oliveira; Souza, Luiz Antonio de [Departamento de Biologia, Universidade Estadual de Maringa, PR (Brazil); Baldoqui, Debora Cristina; Sarragiotto, Maria Helena [Departamento de Quimica, Universidade Estadual de Maringa, PR (Brazil); Silva, Adriano Antonio, E-mail: aasilva@ufac.br [Departamento de Ciencias da Natureza, Universidade Federal do Acre, AC (Brazil)

    2013-09-01

    A phytochemical investigation of Maclura tinctoria fruits yielded five flavonoids, including one prenylated flavonol (licoflavonol) and four prenylated isoflavones (wighteone, derrone, alpinum isoflavone, and 6-(2,2-dimethyl-2H-chromen-6-yl)-2-(1-hydroxy-1-methylethyl) -2,3-dihydro-5H-furo[3,2-g]chromen-5-one). The structures of the isolates were established by analyzing their spectroscopic data. Compound 6-(2,2-dimethyl-2H-chromen-6-yl) -2-(1-hydroxy-1-methylethyl)-2,3-ihydro-5H-furo[3,2-g]chromen-5-one is new and the other isolates are described for the first time in this species. (author)

  7. Flavonoids from Twigs of Millettia leptobotrya Dunn.

    Directory of Open Access Journals (Sweden)

    Zhi Na

    2013-08-01

    Full Text Available A new furanoisoflavone, 2 ' -methoxy-4 ' ,5 ' -methylenedioxy-[2 '' ,3 '' :7,8 ] furanoisoflavone, leptobotryanone ( 1 , and a new natural O-prenylated isoflavone, 4 ' -γ,γ-dimethylallyloxy-5,7-dihydroxyisoflavone ( 2 , were isolated from the twig s of Millettia leptobotrya, together with twelve known flavonoids, 4 ' -γ,γ-dimethylallyloxy-5-hydroxy-7-methoxyisoflavone ( 3 , 2 ' ,6,7-trimethoxy-4 ' ,5 ' -methylenedioxy- isoflavone (4, 2 ' ,7-dimethoxy-4 ' ,5 ' -methylenedioxyisoflavone (5, maximaisoflavone B (6, medicarpin (7 , maackiain (8, genistein (9, biochanin A (10, prunetin (11, chrysoeriol (12 , kaempferol (13 and desmoxyphyllin A (14 The structures of new compounds were elucidated on the basis of spectroscopic data interpretation , including 1D and 2D NMR and HREIMS. Th is is the first phytochemical investigation of this plant.

  8. Flavonoids as modulators of metabolic enzymes and drug transporters.

    Science.gov (United States)

    Miron, Anca; Aprotosoaie, Ana Clara; Trifan, Adriana; Xiao, Jianbo

    2017-06-01

    Flavonoids, natural compounds found in plants and in plant-derived foods and beverages, have been extensively studied with regard to their capacity to modulate metabolic enzymes and drug transporters. In vitro, flavonoids predominantly inhibit the major phase I drug-metabolizing enzyme CYP450 3A4 and the enzymes responsible for the bioactivation of procarcinogens (CYP1 enzymes) and upregulate the enzymes involved in carcinogen detoxification (UDP-glucuronosyltransferases, glutathione S-transferases (GSTs)). Flavonoids have been reported to inhibit ATP-binding cassette (ABC) transporters (multidrug resistance (MDR)-associated proteins, breast cancer-resistance protein) that contribute to the development of MDR. P-glycoprotein, an ABC transporter that limits drug bioavailability and also induces MDR, was differently modulated by flavonoids. Flavonoids and their phase II metabolites (sulfates, glucuronides) inhibit organic anion transporters involved in the tubular uptake of nephrotoxic compounds. In vivo studies have partially confirmed in vitro findings, suggesting that the mechanisms underlying the modulatory effects of flavonoids are complex and difficult to predict in vivo. Data summarized in this review strongly support the view that flavonoids are promising candidates for the enhancement of oral drug bioavailability, chemoprevention, and reversal of MDR. © 2017 New York Academy of Sciences.

  9. Flavonoid accumulation patterns of transparent testa mutants of arabidopsis

    Science.gov (United States)

    Peer, W. A.; Brown, D. E.; Tague, B. W.; Muday, G. K.; Taiz, L.; Murphy, A. S.

    2001-01-01

    Flavonoids have been implicated in the regulation of auxin movements in Arabidopsis. To understand when and where flavonoids may be acting to control auxin movement, the flavonoid accumulation pattern was examined in young seedlings and mature tissues of wild-type Arabidopsis. Using a variety of biochemical and visualization techniques, flavonoid accumulation in mature plants was localized in cauline leaves, pollen, stigmata, and floral primordia, and in the stems of young, actively growing inflorescences. In young Landsberg erecta seedlings, aglycone flavonols accumulated developmentally in three regions, the cotyledonary node, the hypocotyl-root transition zone, and the root tip. Aglycone flavonols accumulated at the hypocotyl-root transition zone in a developmental and tissue-specific manner with kaempferol in the epidermis and quercetin in the cortex. Quercetin localized subcellularly in the nuclear region, plasma membrane, and endomembrane system, whereas kaempferol localized in the nuclear region and plasma membrane. The flavonoid accumulation pattern was also examined in transparent testa mutants blocked at different steps in the flavonoid biosynthesis pathway. The transparent testa mutants were shown to have precursor accumulation patterns similar to those of end product flavonoids in wild-type Landsberg erecta, suggesting that synthesis and end product accumulation occur in the same cells.

  10. Dietary Flavonoids and Gastric Cancer Risk in a Korean Population

    Directory of Open Access Journals (Sweden)

    Hae Dong Woo

    2014-11-01

    Full Text Available Gastric cancer is the most common cancer among men in Korea, and dietary factors are closely associated with gastric cancer risk. We performed a case-control study using 334 cases and 334 matched controls aged 35–75 years. Significant associations were observed in total dietary flavonoids and their subclasses, with the exception of anthocyanidins and isoflavones (OR (95% CI: 0.49 (0.31–0.76, p trend = 0.007 for total flavonoids. However, these associations were not significant after further adjustment for fruits and vegetable consumption (OR (95% CI: 0.62 (0.36–1.09, p trend = 0.458 for total flavonoids. Total flavonoids and their subclasses, except for isoflavones, were significantly associated with a reduced risk gastric cancer in women (OR (95% CI: 0.33 (0.15–0.73, p trend = 0.001 for total flavonoids but not in men (OR (95% CI: 0.70 (0.39–1.24, p trend = 0.393 for total flavonoids. A significant inverse association with gastric cancer risk was observed in flavones, even after additional adjustment for fruits and vegetable consumption in women. No significantly different effects of flavonoids were observed between H. pylori-positive and negative subjects. In conclusion, dietary flavonoids were inversely associated with gastric cancer risk, and these protective effects of dietary flavonoids were prominent in women. No clear differences were observed in the subgroup analysis of H. pylori and smoking status.

  11. Physiological Studies on Pea Tendrils. IV. Flavonoids and Contact Coiling

    Science.gov (United States)

    Jaffe, M. J.; Galston, A. W.

    1967-01-01

    Pea tendrils contain high concentrations of flavonoids, mainly quercetin-triglucosyl-p-coumarate (QGC). QGC is most abundant near the highly responsive apex of the tendril, and least abundant at the base. After mechanical stimulation, and during coiling of the tendril, the QGC titer drops to about 30% of its original value. The kinetics of flavonoid disappearance are significantly correlated with the kinetics of coiling. Aqueous extracts of unstimulated pea tendrils or 10 μm QGC inhibit contact coiling of excised tendrils. Extracts of coiled tendrils do not. The evidence indicates a possible regulatory role for flavonoids in contact coiling. PMID:16656581

  12. Flavonoids as Important Molecules of Plant Interactions with the Environment

    Directory of Open Access Journals (Sweden)

    Justyna Mierziak

    2014-10-01

    Full Text Available Flavonoids are small molecular secondary metabolites synthesized by plants with various biological activities. Due to their physical and biochemical properties, they are capable of participating in plants’ interactions with other organisms (microorganisms, animals and other plants and their reactions to environmental stresses. The majority of their functions result from their strong antioxidative properties. Although an increasing number of studies focus on the application of flavonoids in medicine or the food industry, their relevance for the plants themselves also deserves extensive investigations. This review summarizes the current knowledge on the functions of flavonoids in the physiology of plants and their relations with the environment.

  13. Flavonoids in Helichrysum pamphylicum inhibit mammalian type I DNA topoisomerase.

    Science.gov (United States)

    Topcu, Zeki; Ozturk, Bintug; Kucukoglu, Ozlem; Kilinc, Emrah

    2008-01-01

    DNA topoisomerases are important targets for cancer chemotherapy. We investigated the effects of a methanolic extract of Helichrysum pamphylicum on mammalian DNA topoisomerase I via in vitro plasmid supercoil relaxation assays. The extracts manifested a considerable inhibition of the enzyme's activity in a dose-dependent manner. We also performed a HPLC analysis to identify the flavonoid content of the H. pamphylicum extract and tested the identified flavonoids; luteolin, luteolin-4-glucoside, naringenin, helichrysinA and isoquercitrin, on DNA topoisomerase I activity. The measurement of the total antioxidant capacity of the flavonoid standards suggested that the topoisomerase inhibition might be correlated with the antioxidant capacity of the plant.

  14. New isomeric states in {sup 152,154,156}Nd produced by spontaneous fission of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Phan, X.H.; Theisen, C. [Commissariat l`Energie Atomique de Saclay, Gif sur Yvette (France). DSM/DAPINA/SPhN; Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires de Bordeaux-Gradignan, Domaine du Haut Vigneau, F-33175 Gradignan (France); Belier, G.; Girod, M.; Meot, V.; Peru, S. [Commissariat a l`Energie Atomique de Bruyeres-le-Chatel, DAM/SPN, BP12, F-91680 Bruyeres-le-Chatel (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Institut de Physique Nucleaire de Lyon, F-69622 Villeurbanne Cedex (France)

    1998-04-01

    Isomeric states have been observed in fission-fragments produced by spontaneous fission of {sup 252}Cf. These states are found in neutron rich nuclei of different structure and deformations. About 50 isomeric nuclei have been observed using coincidences between {gamma}-rays identified in EUROGAM II and fission fragments detected in photovoltaic cells (SAPhIR). Lifetimes in the range from 20 ns to 2{mu}s have been measured. Presented calculations based on HFB+D1S force on new measured isomeric states in the {sup 152,154,156}Nd show evidence for K-isomers. (orig.) With 8 figs., 27 refs.

  15. Intrinsic bitterness of flavonoids and isoflavonoids and masking of their taste activity

    NARCIS (Netherlands)

    Roland, W.S.U.

    2014-01-01

    Many flavonoids and isoflavonoids have been associated with beneficial health effects. Therefore, consumption of (iso)flavonoid-rich food products, and enrichment of foods with (iso)flavonoids is becoming increasingly popular. However, several (iso)flavonoids have been reported as bitter.

  16. Flavonoids in baby spinach (Spinacia oleracea L.): Changes during plant growth and storage

    DEFF Research Database (Denmark)

    Bergquist, S. Å. M.; Gertsson, U. E.; Knuthsen, Pia

    2005-01-01

    were analyzed by reversed phase HPLC. Twelve flavonoid peaks were detected. The main flavonoid, making up on average 43% of the total flavonoid concentration, was identified as 5,3',4'-trihydroxy-3-methoxy-6:7-methylenedioxyflavone-4'-glucuronide. Four other flavonoids each contributed 7......The variation in flavonoid concentration and composition was investigated in baby spinach (Spinacia oleracea L.) cv. Emilia sown on three occasions, each harvested at three growth stages at 6-day intervals. After harvest, leaves were stored in polypropylene bags at 2 or 10 degrees C. Flavonoids......-12% of the total flavonoid content. Total flavonoid content was relatively stable during normal retail storage conditions, although some of the individual flavonoid compounds showed considerable variation. The youngest plants had the highest flavonoid concentration, indicating that by harvesting the baby spinach...

  17. Molecular isomerization induced by ultrashort infrared pulses. II. Pump-dump isomerization using pairs of time-delayed half-cycle pulses.

    Science.gov (United States)

    Uiberacker, Christoph; Jakubetz, Werner

    2004-06-22

    We investigate population transfer across the barrier in a double-well potential, induced by a pair of time-delayed single-lobe half-cycle pulses. We apply this setup both to a one-dimensional (1D) quartic model potential and to a three-dimensional potential representing HCN-->HNC isomerization. Overall the results for the two systems are similar, although in the 3D system some additional features appear not seen in the 1D case. The generic mechanism of population transfer is the preparation by the pump pulse of a wave packet involving delocalized states above the barrier, followed by the essentially 1D motion of the delocalized part of wave packet across the barrier, and the eventual de-excitation by the dump pulse to localized states in the other well. The correct timing is given by the well-to-well passage time of the wave packet and its recurrence properties, and by the signs of the field lobes which determine the direction and acceleration or deceleration of the wave packet motion. In the 3D system an additional pump-pump-dump mechanism linked to wave packet motion in the reagent well can mediate isomerization. Since the transfer time and the pulse durations are of the same order of magnitude, there is also a marked dependence of the dynamics and the transfer yield on the pulse duration. Our analysis also sheds light on the pronounced carrier envelope phase dependence previously observed for isomerization and molecular dissociation with one-cycle and sub-one-cycle pulses. (c) 2004 American Institute of Physics.

  18. Quercetin - A Flavonoid Compound from Sarcopyramis bodinieri var ...

    African Journals Online (AJOL)

    The flavonoid compound was identified as quercetin by 1H-. NMR and ESI-MS ... phenolic compounds were isolated, and their .... scored under a fluorescence microscope (Carl. Zeiss .... Antioxidant Properties of Sarcopyramis bodinieri.

  19. Flavonoid Functions in Plants and Their Interactions with Other Organisms

    Directory of Open Access Journals (Sweden)

    Ulrike Mathesius

    2018-04-01

    Full Text Available Flavonoids are structurally diverse secondary metabolites in plants, with a multitude of functions. These span from functions in regulating plant development, pigmentation, and UV protection, to an array of roles in defence and signalling between plants and microorganisms. Because of their prevalence in the human diet, many flavonoids constitute important components of medicinal plants and are used in the control of inflammation and cancer prevention. Advances in the elucidation of flavonoid biosynthesis and its regulation have led to an increasing number of studies aimed at engineering the flavonoid pathway for enhancing nutritional value and plant defences against pathogens and herbivores, as well as modifying the feeding value of pastures. Many future opportunities await for the exploitation of this colourful pathway in crops, pastures, and medicinal plants.

  20. Intervention of Prostate Cancer by a Flavonoid Antioxidant Silymarin

    National Research Council Canada - National Science Library

    Agarwal, Rajesh

    1999-01-01

    ...). We rationalized that targeting this pathway would be useful for PCA intervention, and showed recently that a flavonoid antioxidant silymarin inhibits erbB 1 activation followed by a G 1 arrest...

  1. Isolation and identification of flavonoids from anticancer and ...

    African Journals Online (AJOL)

    Isolation and identification of flavonoids from anticancer and neuroprotective extracts of Trigonella foenum graecum. Shabina Ishtiaq Ahmed, Muhammad Qasim Hayat, Saadia Zahid, Muhammad Tahir, Qaisar Mansoor, Muhammad Ismail, Kristen Keck, Robert Bates ...

  2. Effects of UV light and chromium ions on wood flavonoids

    International Nuclear Information System (INIS)

    Molnárné Hamvas, L.; Németh, K.; Stipta, J.

    2003-01-01

    The individual and simultaneous effect of UV light and chromium ions was investigated by spectrophotometric methods on inert surfaces impregnated with quercetin or robinetin. The UV-VIS spectra of the silica gel plates impregnated with these flavonoids were modified characteristically after irradiating ultraviolet light. Even a half an hour of irradiation has caused irreversible changes in the molecule structure. A certain chemical - presumably complexation - was concluded from the change of spectral bands assigned to flavonoids when impregnated with chromic ions. Hexavalent chromium caused more complex changes in the absorption spectra. The differences in the spectra could indicate either the oxidation and decomposition of flavonoids, or some kind of coordination process and the reduction of hexavalent chromium. The simultaneous application of UV light and chromium ions caused more pronounced effects. The complexation process between chromium(III) and flavonoid was completed

  3. Extraction and Purification of Flavonoids from Radix Puerariae

    African Journals Online (AJOL)

    and preparations are now on sale. ... significant for optimization of extraction, resin selection and ... and flavonoids as indexes, optimize the proper density. ..... system. Sep Purif Technol. 2008; 62: 590-595. 12. Chen JH, Liau BC, Jong TT.

  4. Study the active site of flavonoid applying radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-{gamma}-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  5. Study the active site of flavonoid applying radiation chemistry

    International Nuclear Information System (INIS)

    Wu Jilan; Sun Gang; Zhang Fugen; He Yongke; Li Jiuqiang

    2000-01-01

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-γ-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  6. Comparative Developmental Toxicity of Flavonoids Using an Integrative Zebrafish System.

    Science.gov (United States)

    Bugel, Sean M; Bonventre, Josephine A; Tanguay, Robert L

    2016-11-01

    Flavonoids are a large, structurally diverse class of bioactive naturally occurring chemicals commonly detected in breast milk, soy based infant formulas, amniotic fluid, and fetal cord blood. The potential for pervasive early life stage exposures raises concerns for perturbation of embryogenesis, though developmental toxicity and bioactivity information is limited for many flavonoids. Therefore, we evaluated a suite of 24 flavonoid and flavonoid-like chemicals using a zebrafish embryo-larval toxicity bioassay-an alternative model for investigating developmental toxicity of environmentally relevant chemicals. Embryos were exposed to 1-50 µM of each chemical from 6 to 120 h postfertilization (hpf), and assessed for 26 adverse developmental endpoints at 24, 72, and 120 hpf. Behavioral changes were evaluated in morphologically normal animals at 24 and 72 hpf, at 120 hpf using a larval photomotor response (LPR) assay. Gene expression was comparatively evaluated for all compounds for effects on biomarker transcripts indicative of AHR (cyp1a) and ER (cyp19a1b, esr1, lhb, vtg) pathway bioactivity. Overall, 15 of 24 flavonoids elicited adverse effects on one or more of the developmental or behavioral endpoints. Hierarchical clustering and principle component analyses compared toxicity profiles and identified 3 distinct groups of bioactive flavonoids. Despite robust induction of multiple estrogen-responsive biomarkers, co-exposure with ER and GPER antagonists did not ameliorate toxicity, suggesting ER-independence and alternative modes of action. Taken together, these studies demonstrate that development is sensitive to perturbation by bioactive flavonoids in zebrafish that are not related to traditional estrogen receptor mode of action pathways. This integrative zebrafish platform provides a useful framework for evaluating flavonoid developmental toxicity and hazard prioritization. © The Author 2016. Published by Oxford University Press on behalf of the Society of

  7. Quantitative study of flavonoids in leaves of citrus plants.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M; Koizumi, M; Ito, C; Furukawa, H

    2000-09-01

    Leaf flavonoids were quantitatively determined in 68 representative or economically important Citrus species, cultivars, and near-Citrus relatives. Contents of 23 flavonoids including 6 polymethoxylated flavones were analyzed by means of reversed phase HPLC analysis. Principal component analysis revealed that the 7 associations according to Tanaka's classification were observed, but some do overlap each other. Group VII species could be divided into two different subgroups, namely, the first-10-species class and the last-19-species class according to Tanaka's classification numbers.

  8. Distinguishing PCB Isomeric Congeners with their Gas Chromatographic and Mass Spectrometric Ortho Effect using Comprehensive Gas Chromatography

    Science.gov (United States)

    The 209 polychlorinated biphenyl (PCB) congeners and associated nine isomeric groups (nine groups of PCBs with the same degree of chlorination) have been long recorded as high endocrine disrupting chemicals in the environment. Difficult analytical problems exist, in those frequen...

  9. Communication: An accurate calculation of the S1 C2H2 cis-trans isomerization barrier height

    International Nuclear Information System (INIS)

    Baraban, Joshua H.; Matthews, Devin A.; Stanton, John F.

    2016-01-01

    A high level ab initio calculation of the cis-trans isomerization barrier height in the first excited singlet electronic state of acetylene is found to agree very well with a recent experimental determination.

  10. Plant flavonoids in cancer chemoprevention: role in genome stability.

    Science.gov (United States)

    George, Vazhappilly Cijo; Dellaire, Graham; Rupasinghe, H P Vasantha

    2017-07-01

    Carcinogenesis is a multistage process that involves a series of events comprising of genetic and epigenetic changes leading to the initiation, promotion and progression of cancer. Chemoprevention is referred to as the use of nontoxic natural compounds, synthetic chemicals or their combinations to intervene in multistage carcinogenesis. Chemoprevention through diet modification, i.e., increased consumption of plant-based food, has emerged as a most promising and potentially cost-effective approach to reducing the risk of cancer. Flavonoids are naturally occurring polyphenols that are ubiquitous in plant-based food such as fruits, vegetables and teas as well as in most medicinal plants. Over 10,000 flavonoids have been characterized over the last few decades. Flavonoids comprise of several subclasses including flavonols, flavan-3-ols, anthocyanins, flavanones, flavones, isoflavones and proanthocyanidins. This review describes the most efficacious plant flavonoids, including luteolin, epigallocatechin gallate, quercetin, apigenin and chrysin; their hormetic effects; and the molecular basis of how these flavonoids contribute to the chemoprevention with a focus on protection against DNA damage caused by various carcinogenic factors. The present knowledge on the role of flavonoids in chemoprevention can be used in developing effective dietary strategies and natural health products targeted for cancer chemoprevention. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Bioavailability, metabolism and potential health protective effects of dietary flavonoids

    DEFF Research Database (Denmark)

    Bredsdorff, Lea

    Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several epidemiologi......Dietary flavonoids constitute an important group of potential health protective compounds from fruits, vegetables, and plant-based products such as tea and wine. The beneficial effects of a diet high in flavonoids on the risk of coronary heart disease (CHD) have been shown in several...... of their content. In addition, variation in individual metabolic genotype and microflora may greatly affect the actual flavonoid exposure. The preventive effects of flavonoids on CHD are mainly ascribed to their anti-inflammatory and antioxidant activities. Several mechanisms of anti-inflammatory and antioxidant...... effective absorption of hesperetin and naringenin from the small intestine when consumed as glucosides compared to absorption in the colon VII after microbial degradation of the rhamnoglucosides. In addition it was shown that the conjugate profile was neither affected by the absorption site nor by a 3-fold...

  12. Flavonoid-surfactant interactions: A detailed physicochemical study

    Science.gov (United States)

    Singh, Onkar; Kaur, Rajwinder; Mahajan, Rakesh Kumar

    2017-01-01

    The aim of this article is to study the interactions between flavonoids and surfactants with attention of finding the probable location of flavonoids in micellar media that can be used for controlling their antioxidant behavior. In present study, the micellar and interfacial behavior of twin tailed anionic surfactants viz. sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) in the presence of two flavonoids, namely quercetin (QUE) and kaempferol (KFL) have been studied by surface tension measurements. UV-visible, fluorescence and differential pulse voltammetric (DPV) measurements have been employed to predict the probable location of flavonoids (QUE/KFL) within surfactant (AOT/NaDEHP) aggregates. Dynamic light scattering (DLS) measurements further confirmed the solubilization of QUE/KFL in AOT/NaDEHP aggregates deduced from increased hydrodynamic diameter (Dh) of aggregates in the presence of flavonoids. Both radical scavenging activity (RSA) and degradation rate constant (k) of flavonoids are found to be higher in NaDEHP micelles as compared to AOT micelles.

  13. The biochemistry and medical significance of the flavonoids.

    Science.gov (United States)

    Havsteen, Bent H

    2002-01-01

    Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

  14. Flavonoids and sesquiterpenes of Croton pedicellatus Kunth; Flavonoides e sesquiterpenos de Croton pedicellatus Kunth.

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Elton Luz; Andrade Neto, Manoel; Silveira, Edilberto Rocha; Pessoa, Otilia Deusdenia Loiola [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacases, RJ (Brazil). Dept. de Quimica

    2012-07-01

    The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6{sup -}O-p-coumaroyl-{beta}-galactopyranosyl- kaempferol, 6{sup -}O-p-coumaroyl-{beta}-glucopyranosyl-3{sup -}methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric methods, including HR-ESI-MS, 1D and 2D NMR experiments, and by comparison with previously-described physical and spectral data. (author)

  15. Efficient assembly of polysubstituted pyrroles via a (3 + 2) cycloaddition/skeletal rearrangement/redox isomerization cascade reaction.

    Science.gov (United States)

    Yu, Yuanyuan; Wang, Chunyu; He, Xinze; Yao, Xiaotong; Zu, Liansuo

    2014-07-03

    An unprecedented cascade strategy, used in conjunction with a redox isomerization, for the synthesis of 3-allyl pyrroles is reported. In a single step, readily accessible simple starting materials are transformed into highly substituted pyrroles with high efficiency. The products obtained contain allyl substituents, which can be readily elaborated to other useful functional groups. The reaction proceeds through an unusual (3 + 2) cycloaddition/skeletal rearrangement/redox isomerization pathway.

  16. Antioxidant Flavonoids from Nepeta floccosa Benth.

    Directory of Open Access Journals (Sweden)

    Liaqat Ali

    2015-06-01

    Full Text Available Antioxidants are the substances which significantly delay or prevent the development of age-related degenerative and chronic diseases caused by oxidative damage. Due to this, there is a considerable interest in the identification of lead molecules, which can inhibit the oxidation process or slow it down considerably. Based on the spectrofluorimetric analysis of superoxide and diphenylpicrylhydrazyl radical scavenging ability, the bio-assay guided isolation of methanolic extract of Nepeta floccosa Benth. was carried out. As a result of this study, one new flavanonol named nepetavanol (1 and four known flavonoids; dihydrokaempferol (2, naringenin (3, caulesnarinside (4, and poncirin (5 have been isolated. The structure of the new flavanonol was assigned on the basis of 1H- and 13C-NMR spectra including two-dimensional NMR techniques such as COSY, HMQC, and HMBC experiments and FABMS, EIMS, HR-MS data. Compound 1 , 2, and 3 showed significant activity whereas compounds 4 and 5 showed moderate activity against antioxidant assays.

  17. Flavonoid Regulation of HCN2 Channels*

    Science.gov (United States)

    Carlson, Anne E.; Rosenbaum, Joel C.; Brelidze, Tinatin I.; Klevit, Rachel E.; Zagotta, William N.

    2013-01-01

    The hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels are pacemaker channels whose currents contribute to rhythmic activity in the heart and brain. HCN channels open in response to hyperpolarizing voltages, and the binding of cAMP to their cyclic nucleotide-binding domain (CNBD) facilitates channel opening. Here, we report that, like cAMP, the flavonoid fisetin potentiates HCN2 channel gating. Fisetin sped HCN2 activation and shifted the conductance-voltage relationship to more depolarizing potentials with a half-maximal effective concentration (EC50) of 1.8 μm. When applied together, fisetin and cAMP regulated HCN2 gating in a nonadditive fashion. Fisetin did not potentiate HCN2 channels lacking their CNBD, and two independent fluorescence-based binding assays reported that fisetin bound to the purified CNBD. These data suggest that the CNBD mediates the fisetin potentiation of HCN2 channels. Moreover, binding assays suggest that fisetin and cAMP partially compete for binding to the CNBD. NMR experiments demonstrated that fisetin binds within the cAMP-binding pocket, interacting with some of the same residues as cAMP. Together, these data indicate that fisetin is a partial agonist for HCN2 channels. PMID:24085296

  18. Observation of excited states and isomeric decays in doubly-odd 208Fr

    International Nuclear Information System (INIS)

    Kanjilal, D.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R.; Saha, S.; Bhowmik, R.K.; Gehlot, J.; Jnaneswari, G.; Muralithar, S.; Singh, R.P.; Mukherjee, B.; Mukherjee, G.

    2009-01-01

    The nuclei near the doubly magic 208 Pb are predicted to exhibit various interesting structural phenomena, one of which is a wealth of isomerism. However, a detailed study of high spin states of 211, 212, 213 Fr has already been done. Structure of such trans-Lead nuclei can be interpreted in terms of the shell model states, and the high spin states of these nuclei are interpreted. One of the major interests in the spectroscopic investigation of these nuclei is the role played by the i 13/2 state in creating isomeric levels which decay through transitions of higher muiltipolarity, or are hindered by the close proximity of the levels below. A systematic study of these nuclei will possibly reveal many other interesting structural features

  19. Synthesis of Isomeric Phosphoubiquitin Chains Reveals that Phosphorylation Controls Deubiquitinase Activity and Specificity

    Directory of Open Access Journals (Sweden)

    Nicolas Huguenin-Dezot

    2016-07-01

    Full Text Available Ubiquitin is post-translationally modified by phosphorylation at several sites, but the consequences of these modifications are largely unknown. Here, we synthesize multi-milligram quantities of ubiquitin phosphorylated at serine 20, serine 57, and serine 65 via genetic code expansion. We use these phosphoubiquitins for the enzymatic assembly of 20 isomeric phosphoubiquitin dimers, with different sites of isopeptide linkage and/or phosphorylation. We discover that phosphorylation of serine 20 on ubiquitin converts UBE3C from a dual-specificity E3 ligase into a ligase that primarily synthesizes K48 chains. We profile the activity of 31 deubiquitinases on the isomeric phosphoubiquitin dimers in 837 reactions, and we discover that phosphorylation at distinct sites in ubiquitin can activate or repress cleavage of a particular linkage by deubiquitinases and that phosphorylation at a single site in ubiquitin can control the specificity of deubiquitinases for distinct ubiquitin linkages.

  20. Multi-quasiparticle high-K isomeric states in deformed nuclei

    Directory of Open Access Journals (Sweden)

    Xu F. R.

    2016-01-01

    Full Text Available In the past years, we have made many theoretical investigations on multi-quasiparticle high-K isomeric states. A deformation-pairing-configuration self-consistent calculation has been developed by calculating a configuration-constrained multi-quasiparticle potential energy surface (PES. The specific single-particle orbits that define the high-K configuration are identified and tracked (adiabatically blocked by calculating the average Nilsson numbers. The deformed Woods-Saxon potential was taken to give single-particle orbits. The configuration-constrained PES takes into account the shape polarization effect. Such calculations give good results on excitation energies, deformations and other structure information about multi-quasiparticle high-K isomeric states. Many different mass regions have been investigated.

  1. [Isomeric derivatives of lupinine and epilupinine--organophosphorus inhibitors of cholinesterases].

    Science.gov (United States)

    Basova, N E; Kormilitsyn, B N; Perchenok, A Iu; Rosengart, E V; Saakov, V S; Suvorov, A A

    2012-01-01

    The isomeric-structure analysis data of anticholinesterase action of organophosphorous inhibitors with similar structure help in the search of specific effectors and detection of differences in reactivity of various animals' enzymes. This study compared the data of efficacy in respect of 4 mammal and 5 arthropoda cholinesterase preparations for 26 quinolizidine inhibitors, which molecules contain both the isomeric unbranched and branched alkoxyl radicals in the phosphoryl group, and the epimeric lupinine and epilupinine derivatives in the leaving group. The changes in the alkoxyl radical structure of inhibitor molecules act on their efficacy only with respect to the mammal enzymes ("group" inhibitor specificity). The differences between lupinine and epilupinine derivatives were revealed. Highly specific inhibitors of different enzymes were detected among the tested compounds.

  2. An isomerization-induced cage-breaking process in a molecular glass former below Tg

    International Nuclear Information System (INIS)

    Teboul, V.; Saiddine, M.; Accary, J.-B.; Nunzi, J.-M.

    2011-01-01

    A recent experimental [P. Karageorgiev, D. Neher, B. Schulz, B. Stiller, U. Pietsch, M. Giersig, L. Brehmer, Nature Mater. 4, 699 (2005)] study has found liquidlike diffusion below the glass-transition temperature in azobenzene-containing materials under irradiation. This result suggests that the isomerization-induced massive mass transport that leads to surface relief gratings formation in these materials, is induced by this huge increase of the matrix diffusion coefficient around the probe. In order to investigate the microscopic origin of the increase of the diffusion, we use molecular dynamics simulations of the photoisomerization of probe dispersed red 1 molecules dispersed inside a glassy molecular matrix. Results show that the increased diffusion is due to an isomerization-induced cage-breaking process. A process that explains the induced cooperative motions recently observed in these photoactive materials.

  3. Catalytic Isomerization of Dihydroxyacetone to Lactic Acid and Alkyl Lactates over Hierarchical Zeolites Containing Tin

    Directory of Open Access Journals (Sweden)

    Agnieszka Feliczak-Guzik

    2018-01-01

    Full Text Available Hierarchical zeolites containing tin were obtained, characterized and used in a reaction of catalytic isomerization of dihydroxyacetone (DHA to lactic acid and alkyl lactates. These catalysts are characterized by preserved crystallinity and primary microporosity with the simultaneous existence of secondary porosity regarding mesopores, which facilitates access of large molecules of reagents to active centers. Creation of additional porosity was confirmed by X-ray diffraction and low-temperature nitrogen adsorption/desorption studies. The reaction of dihydroxyacetone isomerization was conducted in different reaction media such as methanol, ethanol or water with the use of two heating methods: microwave radiation and conventional heating. The application of microwave radiation enabled to reduce the reaction time to 1 h and achieve dihydroxyacetone conversion of >90% and high yields of the desired reaction products.

  4. Measurement of millisecond half-lives of isomeric levels in some nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Garg, K C; Khurana, C S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1976-09-01

    Half-lives of 2.7, 14.5, 17, 20, 20.4, 44 and 2230 msec, of isomeric levels in /sup 208/Bi, /sup 88/Y, /sup 75/As, /sup 24/Na, /sup 71/Ge, /sup 114/In and /sup 167/Er respectively have been measured, employing on-line irradiation system. These millisecond isomeric levels are produced by 14.7 MeV neutrons through (n,p), (n,..cap alpha..), (n,n') and (n,2n) reactions on natural target samples. A ..gamma..-ray scintillation detector coupled with NTA-512B, 1024 channel analyzer has been used to follow the decay of the millisecond activities. Deflected deuteron beam bursts have been used to reduce the long-time background to initial count ratios in the decay curves to achieve a better accuracy of measurements.

  5. Collective coordinates and an accompanying metric force in structural isomerization dynamics of molecules

    International Nuclear Information System (INIS)

    Yanao, Tomohiro; Takatsuka, Kazuo

    2003-01-01

    Structural isomerization dynamics of three- and four-atom clusters of vanishing total angular momentum is studied in terms of internal coordinates of n-body systems on the basis of a gauge theory. The so-called principal-axis hyperspherical coordinates are employed effectively as collective variables for the study of isomerization reactions. It turns out that the non-Euclidean metric on the internal space gives rise to a force, which works in response to internal motions called the democratic (kinematic) rotations in the internal space. This metric force generally tends to induce an asymmetry in mass balance of a system, and is coupled with the usual potential force to give rise to trapped motions in the vicinity of the transition states of the cluster. This observation provides a different perspective for the so-called recrossing problem in chemical reaction dynamics

  6. A novel base-induced isomerization gives access to unprecedented (E)-exo-glycals.

    Science.gov (United States)

    Eppe, Guillaume; Dumitrescu, Lidia; Pierrot, Olivier; Li, Tianlei; Pan, Weidong; Vincent, Stéphane P

    2013-08-26

    Bump the base: This study reports the discovery of the base-induced Z-to-E isomerization of exo-glycals bearing an electron-withdrawing group (EWG). The scope of this novel transformation regarding the carbohydrate unit is also discussed. After elucidating the mechanism, preparation of novel (E)-exo- glycals was performed (TBS = tert-butyldimethylsilyl). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Internal conversion of the (13/2+→5/2-) isomeric transition in 199Hg

    International Nuclear Information System (INIS)

    Radha Krishna, K.; Chandrasekhar Rao, M.V.S.; Sree Krishna Murty, G.; Venkateswara Rao, N.; Bhuloka Reddy, S.; Satyanarayana, G.; Sastry, D.L.; Iyer, M.R.; Sahasrabhude, S.G.

    1990-01-01

    The total conversion coefficient of the M4 transition (374 KeV) in the decay of the 13/2 + isomeric state to 5/2 - state in 199 Hg measured using the relative gamma intensity method α T is determined to be 6.34 ± 0.29 in agreement with the theory due to Rosel et al. (author). 1 tab., 3 figs., 11 refs

  8. Sugar Profile, Mineral Content, and Rheological and Thermal Properties of an Isomerized Sweet Potato Starch Syrup

    OpenAIRE

    Dominque, Brunson; Gichuhi, Peter N.; Rangari, Vijay; Bovell-Benjamin, Adelia C.

    2013-01-01

    Currently, corn is used to produce more than 85% of the world's high fructose syrup (HFS). There is a search for alternative HFS substrates because of increased food demand and shrinking economies, especially in the developing world. The sweet potato is a feasible, alternative raw material. This study isomerized a high glucose sweet potato starch syrup (SPSS) and determined its sugar profile, mineral content, and rheological and thermal properties. Rheological and thermal properties were meas...

  9. {sup 13}C-NMR studies on disulfide bond isomerization in bovine pancreatic trypsin inhibitor (BPTI)

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Mitsuhiro [Kumamoto University, Department of Structural BioImaging, Faculty of Life Sciences (Japan); Miyanoiri, Yohei [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan); Terauchi, Tsutomu [Tokyo Metropolitan University, Graduate School of Science and Engineering (Japan); Kainosho, Masatsune, E-mail: kainosho@tmu.ac.jp [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan)

    2016-09-15

    Conformational isomerization of disulfide bonds is associated with the dynamics and thus the functional aspects of proteins. However, our understanding of the isomerization is limited by experimental difficulties in probing it. We explored the disulfide conformational isomerization of the Cys14–Cys38 disulfide bond in bovine pancreatic trypsin inhibitor (BPTI), by performing an NMR line-shape analysis of its Cys carbon peaks. In this approach, 1D {sup 13}C spectra were recorded at small temperature intervals for BPTI samples selectively labeled with site-specifically {sup 13}C-enriched Cys, and the recorded peaks were displayed in the order of the temperature after the spectral scales were normalized to a carbon peak. Over the profile of the line-shape, exchange broadening that altered with temperature was manifested for the carbon peaks of Cys14 and Cys38. The Cys14–Cys38 disulfide bond reportedly exists in equilibrium between a high-populated (M) and two low-populated states (m{sub c14} and m{sub c38}). Consistent with the three-site exchange model, biphasic exchange broadening arising from the two processes was observed for the peak of the Cys14 α-carbon. As the exchange broadening is maximized when the exchange rate equals the chemical shift difference in Hz between equilibrating sites, semi-quantitative information that was useful for establishing conditions for {sup 13}C relaxation dispersion experiments was obtained through the carbon line-shape profile. With respect to the m{sub c38} isomerization, the {sup 1}H-{sup 13}C signals at the β-position of the minor state were resolved from the major peaks and detected by exchange experiments at a low temperature.

  10. Model-Based Analysis and Efficient Operation of a Glucose Isomerization Reactor Plant

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Madsen, Ulrich; Pedersen, Sven

    2015-01-01

    efficiency. The objective of this study is the application of the developed framework on an industrial case study of a glucose isomerization (GI) reactor plant that is part of a corn refinery, with the objective to improve the productivity of the process. Therefore, a multi-scale reactor model...... is developedfor use as a building block for the GI reactor plant simulation. An optimal operation strategy is proposed on the basis of the simulation results...

  11. Isomeric cross section ratios in 55Mn(α, n)58m,gCo reaction

    International Nuclear Information System (INIS)

    Long Xianguan; He Fuqing; Peng Xiufen; Liu Mantian

    1989-01-01

    The isomeric cross section ratios in 55 Mn(α, n) 58m,g Co reaction are measured for incident alpha-particle energies ranging from 10.4 to 26.5 MeV by using activation method and stacked-foil technique. The measured values are compared with theoretical calculations performed by using Huizenga and Vandenbosch method and the values of spin cutoff factor are obtained for product nucleus 58 Co

  12. High spin states in 63Cu. 17/2+ isomeric yrast state

    International Nuclear Information System (INIS)

    Tsan Ung Chan; Bruandet, J.F.; Dauchy, A.; Giorni, A.; Glasser, F.; Morand, C.; Chambon, B.; Drain, D.

    1979-01-01

    The 63 Cu nucleus has been studied via the reaction 61 Ni(α, pnγ), using different in beam γ spectroscopy techniques. An isomeric high-spin Yrast state 17/2 + (tau = 6.1 +- 0.6ns) is located at 4498 keV. The gsub(9/2) shell must be involved to explain positive high-spin states established in this work [fr

  13. [Photoionization ion mobility spectrometry (UV-IMS) for the isomeric volatile organic compounds].

    Science.gov (United States)

    Li, Hu; Niu, Wen-qi; Wang, Hong-mei; Huang, Chao-qun; Jiang, Hai-he; Chu, Yan-nan

    2012-01-01

    The construction and performance study is reported for a newly developed ultraviolet photoionization ion mobility spectrometry (UV-IMS). In the present paper, an UV-IMS technique was firstly developed to detect eleven isomeric volatile organic compounds including the differences in the structure of carbon chain, the style of function group and the position of function group. Their reduced mobility values were determined and increased in this order: linears alcohols homemade UV-IMS was around ppb-ppm.

  14. Inhibition of transmembrane member 16A calcium-activated chloride channels by natural flavonoids contributes to flavonoid anticancer effects.

    Science.gov (United States)

    Zhang, Xuan; Li, Honglin; Zhang, Huiran; Liu, Yani; Huo, Lifang; Jia, Zhanfeng; Xue, Yucong; Sun, Xiaorun; Zhang, Wei

    2017-07-01

    Natural flavonoids are ubiquitous in dietary plants and vegetables and have been proposed to have antiviral, antioxidant, cardiovascular protective and anticancer effects. Transmembrane member 16A (TMEM16A)-encoded Ca 2+ -activated Cl - channels play a variety of physiological roles in many organs and tissues. Overexpression of TMEM16A is also believed to be associated with cancer progression. Therefore, inhibition of TMEM16A current may be a potential target for cancer therapy. In this study, we screened a broad spectrum of flavonoids for their inhibitory activities on TMEM16A currents. A whole-cell patch technique was used to record the currents. The BrdU assay and transwell technique were used to investigate cell proliferation and migration. At a concentration of 100 μM, 10 of 20 compounds caused significant (>50%) inhibition of TMEM16A currents. The four most potent compounds - luteolin, galangin, quercetin and fisetin - had IC 50 values ranging from 4.5 to 15 μM). To examine the physiological relevance of these findings, we also studied the effects of these flavonoids on endogenous TMEM16A currents in addition to cell proliferation and migration in LA795 cancer cells. Among the flavonoids tested, we detected a highly significant correlation between TMEM16A current inhibition and cell proliferation or reduction of migration. This study demonstrates that flavonoids inhibit TMEM16A currents and suggests that flavonoids could have anticancer effects via this mechanism. © 2017 The British Pharmacological Society.

  15. High spin states and isomeric decays in doubly-odd {sup 208}Fr

    Energy Technology Data Exchange (ETDEWEB)

    Kanjilal, D.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R. [Nuclear and Atomic Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Saha, S., E-mail: satyajit.saha@saha.ac.i [Nuclear and Atomic Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Bhowmik, R.K.; Gehlot, J.; Muralithar, S.; Singh, R.P. [Inter University Accelerator Centre, New Delhi 110067 (India); Jnaneswari, G. [Department of Physics, Andhra University, Vishakhapatnam 530003 (India); Mukherjee, G. [Variable Energy Cyclotron Centre, Kolkata 700064 (India); Mukherjee, B. [Department of Physics, Visva Bharati, Santiniketan 731235 (India)

    2010-10-15

    Neutron deficient isotopes of francium (Z=87, N{approx}121-123) as excited nuclei were produced in the fusion-evaporation reaction: {sup 197}Au({sup 16}O, xn) {sup 213-x}Fr at 100 MeV. The {gamma} rays from the residues were observed through the high sensitivity Germanium Clover detector array INGA. The decay of the high spin states and the isomeric states of the doubly-odd {sup 208}Fr nuclei, identified from the known sequence of ground state transitions, were observed. The half-lives of the E{sub {gamma}=}194(2) keV isomeric transition, known from earlier observations, was measured to be T{sub 1/2}=233(18) ns. A second isomeric transition at E{sub {gamma}=}383(2) keV and T{sub 1/2}=33(7) ns was also found. The measured half-lives were compared with the corresponding single particle estimates, based on the level scheme obtained from the experiment.

  16. The study of a new short-life isomeric state in 38K

    International Nuclear Information System (INIS)

    Iordachescu, A.

    1976-01-01

    The 38 K nucleus having a protone and neutron hole coupled with a 40 Ca inert core has a structure analysed easily by the shell model. A new short life, high spin and highly excited isomeric state of the 38 K nucleus has been studied in detail using this model. Theoretical aspects connected with static and dynamic electromagnetic moments of the nucleus state, with the magnetic moment of the nucleus and the selection rules according to the isotopic spin are presented in the case of gamma transitions. Experimentallz/ presented in the case of gamma transitions. Experimentally, it has been used a combination between a natural pulsation of the cyclotron beam and an external pulsation by electrostatic deflexion, thus obtaining a pulsation beam of 12-26 MeV alpha particles. As targets, a series of chemical chlorine combinations have been utilized, the isomeric state being obtained by the reaction 35 Cl(α,n) 38 K, having the isomeric level (1fsub(7/2))sub(7+)sup(2). (author)

  17. Discussion of isomeric ratios in (p, n) and (d, 2n) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Bakhshiyan, T. M., E-mail: tiruhi44@mail.ru [Yerevan State University (Armenia)

    2016-01-15

    Isomeric ratios (IR) in the (p, n) and (d, 2n) reactions are considered. The dependence of IR values on the projectile type and energy, the target- and product-nucleus spin, the spin difference between the isomeric and ground states of products, and the product mass number is discussed. The isomeric ratios for 46 product nuclei (from {sup 44m,g}Sc to {sup 127m,g}Xe) obtained in reactions where target and product nuclei have identical mass numbers were calculated at energies from the reaction threshold to 50 MeV (with a step of ΔE = 1 MeV). The calculations in question were performed with the aid of the TALYS 1.4 code package. The calculated IR values were compared with their experimental counterparts available from the literature (EXFOR database). In the majority of cases, the calculated IR values agree well with the experimental data in question. It is noteworthy that the IR values obtained in (d, 2n) reactions are substantially greater than those in (p, n) reactions.

  18. Photo-isomerization and oxidation of bilirubin in mammals is dependent on albumin binding.

    Science.gov (United States)

    Goncharova, Iryna; Jašprová, Jana; Vítek, Libor; Urbanová, Marie

    2015-12-01

    The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel analytical concept in the study of linear tetrapyrroles metabolic processes based on an in-depth mapping of binding sites in the structure of human serum albumin (HSA). A combination of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling methods was used for recognition of the binding site for BR, its derivatives (mesobilirubin and bilirubin ditaurate), and the products of the photo-isomerization and oxidation (lumirubin, biliverdin, and xanthobilirubic acid) on HSA. The CD spectra and fluorescent quenching of the Trp-HSA were used to calculate the binding constants. The results of the CD displacement experiments performed with hemin were interpreted together with the findings of molecular docking performed on the pigment-HSA complexes. We estimated that Z,Z-BR and its metabolic products bind on two independent binding sites. Our findings support the existence of a reversible antioxidant redox cycle for BR and explain an additional pathway of the photo-isomerization process (increase of HSA binding capacity; the excess free [unbound] BR can be converted and also bound to HSA). Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Spectroscopic and Theoretical Identification of Two Thermal Isomerization Pathways for Bistable Chiral Overcrowded Alkenes.

    Science.gov (United States)

    Kistemaker, Jos C M; Pizzolato, Stefano F; van Leeuwen, Thomas; Pijper, Thomas C; Feringa, Ben L

    2016-09-12

    Chiroptical molecular switches play an important role in responsive materials and dynamic molecular systems. Here we present the synthesis of four chiral overcrowded alkenes and the experimental and computational study of their photochemical and thermal behavior. By irradiation with UV light, metastable diastereoisomers with opposite helicity were generated through high yielding E-Z isomerizations. Kinetic studies on metastable 1-4 using CD spectroscopy and HPLC analysis revealed two pathways at higher temperatures for the thermal isomerization, namely a thermal E-Z isomerization (TEZI) and a thermal helix inversion (THI). These processes were also studied computationally whereby a new strategy was developed for calculating the TEZI barrier for second-generation overcrowded alkenes. To demonstrate that these overcrowded alkenes can be employed as bistable switches, photochromic cycling was performed, which showed that the alkenes display good selectivity and fatigue resistance over multiple irradiation cycles. In particular, switch 3 displayed the best performance in forward and backward photoswitching, while 1 excelled in thermal stability of the photogenerated metastable form. Overall, the alkenes studied showed a remarkable and unprecedented combination of switching properties including dynamic helicity, reversibility, selectivity, fatigue resistance, and thermal stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Preclinical Evaluation of the Synthetic Adjuvant SQS-21 and its Constituent Isomeric Saponins

    Science.gov (United States)

    Ragupathi, Govind; Damani, Payal; Deng, Kai; Adams, Michelle M.; Hang, Jianfeng; George, Constantine; Livingston, Philip O.; Gin, David Y.

    2010-01-01

    The saponin fraction QS-21 from Quillaja saponaria has been demonstrated to be a potent immunological adjuvant when mixed with keyhole limpet hemocyanin conjugate vaccines, as well as with other classes of subunit antigen vaccines. QS-21 adjuvant is composed of two isomers that include the apiose and xylose forms in a ratio of 65:35, respectively. The chemical syntheses of these two isomers in pure form have recently been disclosed. Herein we describe detailed in vivo immunological evaluations of these synthetic QS-21 isomeric constituents, employing the GD3-KLH melanoma antigen. With this vaccine construct, high antibody titers against GD3 ganglioside and KLH were elicited when GD3-KLH was co-administered with adjuvant, either as the individual separate synthetic QS-21 isomers (SQS-21-Api or SQS-21-Xyl), or as its reconstituted 65:35 isomeric mixture (SQS-21). These antibody titer levels were comparable to that elicited by vaccinations employing naturally derived QS-21 (PQS-21). Moreover, toxicities of the synthetic saponin adjuvants were also found to be comparable to that of naturally derived PQS-21. These findings demonstrate unequivocally that the adjuvant activity of QS-21 resides in these two principal isomeric forms, and not in trace contaminants within the natural extracts. This lays the foundation for future exploration of structure-function correlations to enable the discovery of novel saponins with increased potency, enhanced stability, and attenuated toxicity. PMID:20450868

  1. Thermal isomerization of azobenzenes: on the performance of Eyring transition state theory

    Science.gov (United States)

    Rietze, Clemens; Titov, Evgenii; Lindner, Steven; Saalfrank, Peter

    2017-08-01

    The thermal Z\\to E (back-)isomerization of azobenzenes is a prototypical reaction occurring in molecular switches. It has been studied for decades, yet its kinetics is not fully understood. In this paper, quantum chemical calculations are performed to model the kinetics of an experimental benchmark system, where a modified azobenzene (AzoBiPyB) is embedded in a metal-organic framework (MOF). The molecule can be switched thermally from cis to trans, under solvent-free conditions. We critically test the validity of Eyring transition state theory for this reaction. As previously found for other azobenzenes (albeit in solution), good agreement between theory and experiment emerges for activation energies and activation free energies, already at a comparatively simple level of theory, B3LYP/6-31G* including dispersion corrections. However, theoretical Arrhenius prefactors and activation entropies are in qualitiative disagreement with experiment. Several factors are discussed that may have an influence on activation entropies, among them dynamical and geometric constraints (imposed by the MOF). For a simpler model—Z\\to E isomerization in azobenzene—a systematic test of quantum chemical methods from both density functional theory and wavefunction theory is carried out in the context of Eyring theory. Also, the effect of anharmonicities on activation entropies is discussed for this model system. Our work highlights capabilities and shortcomings of Eyring transition state theory and quantum chemical methods, when applied for the Z\\to E (back-)isomerization of azobenzenes under solvent-free conditions.

  2. Concurrent Mass Measurement and Laser Spectroscopy for Unambiguous Isomeric State Assignment

    Science.gov (United States)

    Lascar, Daniel; Babcock, Carla; Henderson, Jack; Pearson, Matt

    2017-09-01

    Recent work by the TITAN group at TRIUMF on isomeric state mass measurements of odd-A, neutron-rich cadmium nuclei has shown a disconnect between experiment and theory in 127 g , mCd. The spin and parity assignments of the ground and isomeric states are assigned as 3/2+ and 11/2-, respectively, primarily via systematic arguments. Conversely, state of the art shell model and ab initio calculations show a reversal of the states, predicting a ground state of 11/2- and a 3/2+ isomer. Penning Trap Mass Spectrometry (PTMS) can measure the energy separation between the ground state and the isomer without ambiguity but cannot, on its own, comment on the spin and parity. Collinear Laser Spectroscopy (CLS) experiments have been performed on 127Cd and have elegantly demonstrated the existence of both 3/2+ and 11/2- states. What CLS cannot do, on its own, is assign an ordering to those states. If, however, a PTMS and CLS experiment could be performed concurrently using identical beams from the same facility then there exists sufficient information shared between both experiments that a definitive assignment can be made. We present a concept for a new slate of measurements using existing experimental facilities simultaneously, with shared resources, to definitively assign spin and parity for ground and isomeric states in short-lived nuclei.

  3. Yields and isomeric ratio of xenon and krypton isotopes from thermal neutron fission of 235U

    International Nuclear Information System (INIS)

    Hsu, S.S.; Lin, J.T.; Yang, C.M.; Yu, Y.W.

    1981-01-01

    The experimental cumulative yields of 85 Kr/sup m/, 87 Kr, 88 Kr, 133 Xe/sup g/, 135 Xe/sup m/, and 135 Xe/sup g/ and the independent isomeric yield of 133 Xe/sup m/ in the thermal neutron fission of 235 U have been measured by the gas chromatographic method. The independent yields of 133 Xe/sup g/, 135 Xe/sup m/, and 135 Xe/sup g/ were deduced with the aid of 133 I and 135 I data. The isomeric yield ratios of 133 Xe and 135 Xe have been computed and compared with theoretical values since they have the same high spin state J = 11/2 - and low spin ground state J = 3/2 + . The influence of the shell effect on the fission isomeric yield ratio is discussed. From the measured independent yield of Xe isotopes plus the reported data, the Xe-isotopic distribution curve has been constructed. The curve is compared with the isotopic distribution curves of Xe isotopes formed in 11.5 GeV proton interactions with 238 U and Cs isotopes formed in 24 GeV proton interactions with 238 U. Upon fitting the yield curves we find that only those products with N/Z> or =1.48 fit a curve typical of a binary fission process

  4. Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

    Science.gov (United States)

    Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

    2017-06-01

    Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

  5. Peptide models of protein metastable binding sites: competitive kinetics of isomerization and hydrolysis.

    Science.gov (United States)

    Khan, S A; Sekulski, J M; Erickson, B W

    1986-09-09

    alpha 2-Macroglobulin and the complement components C3 and C4 each contain a metastable binding site that is essential for covalent attachment. Two cyclic peptides are useful models of these unusual protein sites. Five-membered lactam 1 (CH3CO-Gly-Cys-Gly-Glu-Glp-Asn-NH2) contains an internal residue of pyroglutamic acid (Glp). Fifteen-membered thiolactone 2 (CH3CO-Gly-Cys-Gly-Glu-Glu-Asn-NH2 15-thiolactone) contains a thiol ester bond between Cys-2 and Glu-5. These isomeric hexapeptides are spontaneously interconverted in water. Competing with the two isomerization reactions are three reactions involving hydrolysis of 1 and 2. These five processes were found to occur simultaneously under physiologic conditions (phosphate-buffered saline, pH 7.3, 37 degrees C). Best estimates of the five rate constants for these apparent first-order reactions were obtained by comparing the observed molar percentages of peptides 1-4 with those calculated from a set of exponential equations. Both isomerization reactions (ring expansion of 1 to 2, k1 = 6.4 X 10(-5) s-1; ring contraction of 2 to 1, k-1 = 69 X 10(-5) s-1) proceeded faster than any of the hydrolysis reactions: alpha-cleavage of 1 with fragmentation to form dipeptide 3 (k2 = 3.3 X 10(-5) s-1), gamma-cleavage of 1 with ring opening to yield mercapto acid 4 (k3 = 0.35 X 10(-5) s-1), and hydrolysis of 2 with ring opening to give 4 (k4 = 1.9 X 10(-5) s-1). The isomerization rate ratio (k1/k-1 = 10.9) agreed with the isomer ratio at equilibrium (1:2 = 11 starting from 1 and 10 starting from 2). The alpha/gamma regioselectivity ratio (k2/k3 = 9.7) for hydrolysis of the internal Glp residue of 1 was consistent with results for model tripeptides. Part of the chemistry of the protein metastable binding sites can be explained by similar isomerization and hydrolysis reactions.

  6. Enhancing Human Cognition with Cocoa Flavonoids

    Directory of Open Access Journals (Sweden)

    Valentina Socci

    2017-05-01

    Full Text Available Enhancing cognitive abilities has become a fascinating scientific challenge, recently driven by the interest in preventing age-related cognitive decline and sustaining normal cognitive performance in response to cognitively demanding environments. In recent years, cocoa and cocoa-derived products, as a rich source of flavonoids, mainly the flavanols sub-class, have been clearly shown to exert cardiovascular benefits. More recently, neuromodulation and neuroprotective actions have been also suggested. Here, we discuss human studies specifically aimed at investigating the effects of acute and chronic administration of cocoa flavanols on different cognitive domains, such as executive functions, attention and memory. Through a variety of direct and indirect biological actions, in part still speculative, cocoa and cocoa-derived food have been suggested to possess the potential to counteract cognitive decline and sustain cognitive abilities, particularly among patients at risk. Although still at a preliminary stage, research investigating the relations between cocoa and cognition shows dose-dependent improvements in general cognition, attention, processing speed, and working memory. Moreover, cocoa flavanols administration could also enhance normal cognitive functioning and exert a protective role on cognitive performance and cardiovascular function specifically impaired by sleep loss, in healthy subjects. Together, these findings converge at pointing to cocoa as a new interesting nutraceutical tool to protect human cognition and counteract different types of cognitive decline, thus encouraging further investigations. Future research should include complex experimental designs combining neuroimaging techniques with physiological and behavioral measures to better elucidate cocoa neuromodulatory properties and directly compare immediate versus long-lasting cognitive effects.

  7. K isomerism and collectivity in neutron-rich rare-earth isotopes

    Science.gov (United States)

    Patel, Zena

    Neutron-rich rare-earth isotopes were produced by in-flight fission of 238U ions at the Radioactive Isotope Beam Factory (RIBF), RIKEN, Japan. In-flight fission of a heavy, high-intensity beam of 238U ions on a light target provides the cleanest secondary beams of neutron-rich nuclei in the rare-earth region of isotopes. In-flight fission is advantageous over other methods of nuclear production, as it allows for a secondary beam to be extracted, from which the beam species can be separated and identified. The excited states of nuclei are studied by delayed isomeric or beta-delayed gamma-ray spectroscopy. New K isomers were found in Sm (Z=62), Eu (Z=63), and Gd (Z=64) isotopes. The key results are discussed here. Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time. The K-isomeric states in 166Gd and 164Sm are due to 2-quasiparticle configurations. Based on the decay patterns and potential energy surface calculations, including beta6 deformation, both isomers are assigned a (6-) spin-parity. The half-lives of the isomeric states have been measured to be 950(60)ns and 600(140)ns for 166Gd and 164Sm respectively. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground state band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100) respectively, presents evidence for the predicted deformed shell closure at N=100. A 4-quasiparticle isomeric state has been discovered in 160Sm: the lightest deformed nucleus with a 4-quasiparticle isomer to date. The isomeric state is assigned an (11+) spin-parity with a measured half-life of 1.8(4)us. The (11+) isomeric state decays into a rotational band structure, based on a (6-) v5/2-[523] ⊗ v7/2+[633] bandhead, determined from the extracted gK-gR values. Potential energy surface and blocked BCS calculations were performed in the deformed midshell region

  8. Inhibition effect on lipid oxidation of irradiated pork by adding hawthorn flavonoid extract

    International Nuclear Information System (INIS)

    Wang Xiaoming; Liu Chao; Cao Lei; Li Kexi

    2011-01-01

    The antioxidant activity of hawthorn flavonoid extract and its inhibition effect on irradiated pork lipid oxidant were investigated. The results showed that hawthorn flavonoids had efficient scavenging effect on DPPH free radicals (DPPH ·), and the scavenging rate reached 56% while 2 ml of 0.035 mg/ml hawthorn flavonoid extract was added. Hawthorn flavonoid extract can inhibition the lipid oxidation of irradiated pork effectively and it showed a stronger inhibition ability while the hawthorn flavonoid extract were used together with Vc. It is concluded that can decrease the lipid oxidation of pork, hawthorn flavonoid extract is a remarkable natural antioxidant. (authors)

  9. Flavonoids, Thyroid Iodide Uptake and Thyroid Cancer-A Review.

    Science.gov (United States)

    Gonçalves, Carlos F L; de Freitas, Mariana L; Ferreira, Andrea C F

    2017-06-12

    Thyroid cancer is the most common malignant tumor of the endocrine system and the incidence has been increasing in recent years. In a great part of the differentiated carcinomas, thyrocytes are capable of uptaking iodide. In these cases, the main therapeutic approach includes thyroidectomy followed by ablative therapy with radioiodine. However, in part of the patients, the capacity to concentrate iodide is lost due to down-regulation of the sodium-iodide symporter (NIS), the protein responsible for transporting iodide into the thyrocytes. Thus, therapy with radioiodide becomes ineffective, limiting therapeutic options and reducing the life expectancy of the patient. Excessive ingestion of some flavonoids has been associated with thyroid dysfunction and goiter. Nevertheless, studies have shown that some flavonoids can be beneficial for thyroid cancer, by reducing cell proliferation and increasing cell death, besides increasing NIS mRNA levels and iodide uptake. Recent data show that the flavonoids apingenin and rutin are capable of increasing NIS function and expression in vivo. Herein we review literature data regarding the effect of flavonoids on thyroid cancer, besides the effect of these compounds on the expression and function of the sodium-iodide symporter. We will also discuss the possibility of using flavonoids as adjuvants for therapy of thyroid cancer.

  10. Non-alcoholic Fatty Liver Disease: Beneficial Effects of Flavonoids.

    Science.gov (United States)

    Akhlaghi, Masoumeh

    2016-10-01

    Non-alcoholic fatty liver disease (NAFLD) has been known as the hepatic feature of metabolic syndrome. Extra fat depots, especially in visceral areas, develop insulin resistance as a result of mild oxidation and inflammation. Insulin resistance induces lipolysis and releases free fatty acids into the circulation, where they are transported to the liver. In the liver, free fatty acids are converted to triglycerides and accumulate, causing simple steatosis that, if left untreated, can lead to steatohepatitis, and subsequently liver necrosis and cirrhosis.Flavonoids, a group of plant compounds with incredible biological characteristics, have shown advantages in pathological conditions. Beneficial effects of flavonoids against NAFLD and its related disorders have been observed in both animal and human studies. Various mechanisms have been found for their protection. Flavonoids prevent hepatosteatosis by increasing fatty acid oxidation in the liver. They can also reduce caloric intake and decrease body weight and fat deposition in visceral tissues. Flavonoids are unique antioxidants that exert their beneficial effects through inhibition of nuclear factor κB, thereby attenuating release of inflammatory cytokines, which are triggers of insulin resistance. Finally, flavonoids have shown to increase adiponectin, improve insulin sensitivity and glucose tolerance, correct dyslipidemia, and reduce blood pressure in patients with NAFLD. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Chlorinated Flavonoids Modulate the Inflammatory Process in Human Blood.

    Science.gov (United States)

    Proença, Carina; Ribeiro, Daniela; Soares, Tânia; Tomé, Sara M; Silva, Artur M S; Lima, José L F C; Fernandes, Eduarda; Freitas, Marisa

    2017-08-01

    Flavonoids are known to react with neutrophil-generated hypochlorous acid (HOCl) at inflammation loci to form stable mono- and dichlorinated products. Some of these products have been shown to retain or even enhance their inflammatory potential, but further information is required in a broader approach to inflammatory mechanisms. In that sense, we performed an integrated evaluation on the anti-inflammatory potential of a panel of novel chlorinated flavonoids and their parent compounds, in several steps of the complex inflammatory cascade, namely, in the activity of cyclooxygenase (COX)-1 and COX-2, and in the production of cytokines [interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)], and the chemokine, IL-8, as well as in the production of reactive species, using human whole blood as a representative in vitro model, establishing, whenever possible, a structure-activity relationship. Although luteolin was the most active compound, chlorinated flavonoids demonstrated a remarkable pattern of activity for the resolution of the inflammatory processes. Our results demonstrated that 6-chloro-3',4',5,7-tetrahydroxyflavone deserves scientific attention due to its ability to modulate the reactive species and cytokines/chemokine production. In this regard, the therapeutic potential of flavonoids' metabolites, and in this particular case the chlorinated flavonoids, should not be neglected.

  12. Flavonoids, Thyroid Iodide Uptake and Thyroid Cancer—A Review

    Science.gov (United States)

    Gonçalves, Carlos F. L.; de Freitas, Mariana L.; Ferreira, Andrea C. F.

    2017-01-01

    Thyroid cancer is the most common malignant tumor of the endocrine system and the incidence has been increasing in recent years. In a great part of the differentiated carcinomas, thyrocytes are capable of uptaking iodide. In these cases, the main therapeutic approach includes thyroidectomy followed by ablative therapy with radioiodine. However, in part of the patients, the capacity to concentrate iodide is lost due to down-regulation of the sodium-iodide symporter (NIS), the protein responsible for transporting iodide into the thyrocytes. Thus, therapy with radioiodide becomes ineffective, limiting therapeutic options and reducing the life expectancy of the patient. Excessive ingestion of some flavonoids has been associated with thyroid dysfunction and goiter. Nevertheless, studies have shown that some flavonoids can be beneficial for thyroid cancer, by reducing cell proliferation and increasing cell death, besides increasing NIS mRNA levels and iodide uptake. Recent data show that the flavonoids apingenin and rutin are capable of increasing NIS function and expression in vivo. Herein we review literature data regarding the effect of flavonoids on thyroid cancer, besides the effect of these compounds on the expression and function of the sodium-iodide symporter. We will also discuss the possibility of using flavonoids as adjuvants for therapy of thyroid cancer. PMID:28604619

  13. Radioprotective effects of antioxidative plant flavonoids in mice

    International Nuclear Information System (INIS)

    Shimoi, Kayoko; Masuda, Shuichi; Shen, Bingrong; Furugori, Michiyo; Kinae, Naohide

    1996-01-01

    Radioprotective effects of tea infusions and plant flavonoids were investigated by using the micronucleus test for anticlastogenic activity and the thiobarbituric acid assay for antioxidative activity. A single gastric intubation of rooibos tea (Aspalathus linearis) infusion at 1 ml per mouse 2 h prior to γ-ray irradiation (1.5 Gy) reduced the frequency of micronucleated reticulocytes (MNRETs). After the fractionation of rooibos tea infusion, the flavonoid fraction was found to be most anticlastogenic and antioxidative. From this fraction, luteolin was isolated as an effective component. Then, anticlastogenic effects of 12 flavonoids containing luteolin and their antioxidative activities against lipid peroxidation by Fenton's reagent were examined. A good correlation (r=0.717) was observed between both activities. Luteolin showed the most effective potency. A gastric intubation of luteolin (10 μmol/kg) 2 h prior to γ-ray irradiation (6 Gy) suppressed lipid peroxidation in mouse bone marrow and spleen and a trend of protective effect of luteolin against the decrease of endogenous ascorbic acid in mouse bone marrow after γ-ray irradiation (3 Gy) was observed. These results suggest that plant flavonoids, which show antioxidative potency in vitro, work as antioxidants in vivo and their radioprotective effects may be attributed to their scavenging potency towards free radicals such as hydroxyl radicals. Therefore, the flavonoids contained in tea, vegetables and fruits seem to be important as antioxidants in the human diet

  14. Luteolin, a flavonoid, inhibits AP-1 activation by basophils

    International Nuclear Information System (INIS)

    Hirano, Toru; Higa, Shinji; Arimitsu, Junsuke; Naka, Tetsuji; Ogata, Atsushi; Shima, Yoshihito; Fujimoto, Minoru; Yamadori, Tomoki; Ohkawara, Tomoharu; Kuwabara, Yusuke; Kawai, Mari; Matsuda, Hisashi; Yoshikawa, Masayuki; Maezaki, Naoyoshi; Tanaka, Tetsuaki; Kawase, Ichiro; Tanaka, Toshio

    2006-01-01

    Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812 cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1

  15. Phytochemical studies of flavonoids from polygonum glabrum L of Sudan

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, Intisar Sirour [Faculty of Science, University of Khartoum, Khartoum (Sudan)

    1996-01-01

    A semi- aquatic plant, Polygnum glabrum wild of the family polygonaceae was reported in traditional medicine of Sudan as anthelmintic and as a remedy against intestinal colics.The literature reported the isolation and structure elucidation of the bioactive agents as being sequi terpenes. The flavonoids of the Sudanese species were not investigated before. The present work consisted of phyto chemical study of the leaves of Polygonum galbrum wild. Before experimentation, a through authentication of the plant was done to correct previously reported errors. In the first stages a phyto chemical screening was made which confirmed the presence of flavonoid compounds in higher amounts than the other classes of natural products present in the plant. Different chromatographic techniques of isolation were assayed but the fractionation of flavonoids was successfully done with preparative thin layer chromatographic techniques. Yellow crystals, namely (two compounds) were obtained in pure form and identified as being flavonoids. Spectral studies were performed on Infra-Red and Ultra- Violet spectrophotometers. The computerized Ultra- Violet spectrophotometer allowed us to obtain complete data about the studied compounds. Structure elucidation was attempted and the structure of the isolated flavonoids were suggested as being Isorhamnetin and Diosmetin. (Author)

  16. Antioxidant and Hepatoprotective Activities of Flavonoids from Bauhinia hookeri

    Directory of Open Access Journals (Sweden)

    Eman Al-Sayed

    2016-05-01

    Full Text Available In a previous study, the total ethanol extract of Bauhinia hookeri showed a significant hepatoprotective effect in CCl 4-induced toxicity model in mice. However, the active components responsible for the activity were not identified. Therefore, this study was undertaken to determine if the activity of B. hookeri extract is due to its flavonoid content. The hepatoprotective activity of B. hookeri flavonoids was determined by measuring the activities of alanine aminotransferase (ALT and aspartate aminotransferase (AST in the culture medium of HepG2 cells challenged with CCl 4. The lipid peroxidation and antioxidant parameters, superoxide dismutase (SOD and glutathione (GSH were estimated in the cell lysates. The isolated flavonoids were identified by mass, UV and NMR spectral data. This study revealed that B. hookeri flavonoid fraction and its pure compounds ( kaempferol 3-O-β- D-glucoside, quercetin 3-O-β- D-glucoside and c atechin 3-O-α- L-rhamnoside possess a promising hepatoprotective activity as evidenced from the normalized levels of ALT and AST. This was attributed partly to their potent antioxidant activity as demonstrated by the increased GSH levels, SOD activity and reduced lipid peroxidation. The whole flavonoid fraction showed the highest cytoprotective activity and was more effective than silymarin. This study highlights a promising natural hepatoprotective remedy derived from B. hookeri.

  17. Highly Oxygenated Flavonoids from the Leaves of Nicotiana plumbaginifolia (Solanaceae

    Directory of Open Access Journals (Sweden)

    Md. Shafiullah Shajib

    2017-11-01

    Full Text Available Nicotiana plumbaginifolia Viv. is an annual herb of the family Solanaceae, which grows abundantly in the weedy lands of Bangladesh . This plant possesses analgesic, antibacterial, anti-anxiety and hepatoprotective properties, and produces various phenolic compounds including flavonoids. The present study afforded determination of total phenolic and flavonoid contents, and for the first time, the isolation and characterization of highly oxygenated flavonoids, e.g., 3,3' ,5,6,7,8-hexamethoxy- 4',5'-methylenedioxyflavone (1, 3,3' ,4' ,5',5,6,7,8-octamethoxyflavone (2, exoticin, 6,7,4',5'-dimethylenedioxy-3,5,3'-trimethoxyflavone (3 and ( 3,3' ,4',5,5',8-hexamethoxy-6,7-methylenedioxyflavone (4 from the leaves of N. plumbaginifolia . All these flavonoids are rather rare natural products, and only found in a few genera, e.g.,Polygonum and Murraya. The structures of the isolated flavonoids were elucidated by comprehensive spectroscopic analyses, e.g., UV, 1H, 13C NMR, DEPT, HSQC, HMBC and MS.

  18. Flavonoids Inhibit the Respiratory Burst of Neutrophils in Mammals

    Directory of Open Access Journals (Sweden)

    Milan Ciz

    2012-01-01

    Full Text Available Neutrophils represent the front-line defence cells in protecting organisms against infection and play an irreplaceable role in the proper performance of the immune system. As early as within the first minutes of stimulation, neutrophilic NADPH oxidase is activated, and cells release large quantities of highly toxic reactive oxygen species (ROS. These oxidants can be highly toxic not only for infectious agents but also for neighboring host tissues. Since flavonoids exhibit antioxidant and anti-inflammatory effects, they are subjects of interest for pharmacological modulation of ROS production. The present paper summarizes contemporary knowledge on the effects of various flavonoids on the respiratory burst of mammalian neutrophils. It can be summarized that the inhibitory effects of flavonoids on the respiratory burst of phagocytes are mediated via inhibition of enzymes involved in cell signaling as well as via modulation of redox status. However, the effects of flavonoids are even more complex, and several sites of action, depending upon the flavonoid structure and way of application, are included.

  19. Regulation of Flavonoid Biosynthetic Genes in Germinating Arabidopsis Seedlings.

    Science.gov (United States)

    Kubasek, WL; Shirley, BW; McKillop, A; Goodman, HM; Briggs, W; Ausubel, FM

    1992-01-01

    Many higher plants, including Arabidopsis, transiently display purple anthocyanin pigments just after seed germination. We observed that steady state levels of mRNAs encoded by four flavonoid biosynthetic genes, PAL1 (encoding phenylalanine ammonia-lyase 1), CHS (encoding chalcone synthase), CHI (encoding chalcone isomerase), and DFR (encoding dihydroflavonol reductase), were temporally regulated, peaking in 3-day-old seedlings grown in continuous white light. Except for the case of PAL1 mRNA, mRNA levels for these flavonoid genes were very low in seedlings grown in darkness. Light induction studies using seedlings grown in darkness showed that PAL1 mRNA began to accumulate before CHS and CHI mRNAs, which, in turn, began to accumulate before DFR mRNA. This order of induction is the same as the order of the biosynthetic steps in flavonoid biosynthesis. Our results suggest that the flavonoid biosynthetic pathway is coordinately regulated by a developmental timing mechanism during germination. Blue light and UVB light induction experiments using red light- and dark-grown seedlings showed that the flavonoid biosynthetic genes are induced most effectively by UVB light and that blue light induction is mediated by a specific blue light receptor. PMID:12297632

  20. Stability and isomerization reactions of phenyl cation C{sub 6}H{sub 5}{sup +} isomers

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Dandan [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Yang, Xue [College of Science, Jilin Institute of Chemical Technology, Jilin 132022 (China); Zhang, Xiaomei; Shan, Shimin [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Xu, Haifeng, E-mail: xuhf@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China); Yan, Bing, E-mail: yanbing@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun 130012 (China)

    2016-03-01

    Highlights: • A total of 60 isomers of C{sub 6}H{sub 5}{sup +} cations were obtained at density functional theory. • The stability and isomerization reactions of C{sub 6}H{sub 5}{sup +} isomers were performed. • The structures, frequencies, thermodynamic properties of isomers were summarized. • Ring to ring or chain isomerization pathways were investigated using IRC method. • Result shows reactions contain hydrogen transfer, bond broken and reconstruction. - Abstract: As a key polyatomic molecular cation that plays a pivotal role in growth of the polycyclic aromatic hydrocarbons, phenyl cation C{sub 6}H{sub 5}{sup +} exhibits various isomers and isomerization reactions. Investigation on the structure and stability of the isomers as well as the isomerization is important for better understanding the chemical reactions involving C{sub 6}H{sub 5}{sup +} cations. In this work, we have performed a theoretical study on the stability and isomerization reactions of C{sub 6}H{sub 5}{sup +} isomers at density functional theory B3LYP/6-311G (d, p) level. We have obtained a total of 60 isomers of C{sub 6}H{sub 5}{sup +} cations, most of which are reported for the first time. The geometries, vibrational frequencies, thermodynamic properties and stability of 28 out of 60 isomers have been summarized in detail. Different ring-to-ring and ring-to-chain isomerization pathways, which are connected via 28 transition states, have been investigated using the intrinsic reaction coordinate method. The results show that the isomerization reactions occur via hydrogen migration followed by bond-breaking and reconstruction.

  1. Different biosynthesis patterns among flavonoid 3-glycosides with distinct effects on accumulation of other flavonoid metabolites in pears (Pyrus bretschneideri Rehd..

    Directory of Open Access Journals (Sweden)

    Rui Zhai

    Full Text Available Flavonoid biosynthesis profile was clarified by fruit bagging and re-exposure treatments in the green Chinese pear 'Zaosu' (Pyrus bretschneideri Rehd. and its red mutant 'Red Zaosu'. Two distinct biosynthesis patterns of flavonoid 3-glycosides were found in 'Zaosu' pear. By comparison with 'Red Zaosu', the biosynthesis of flavonoid 3-galactosides and flavonoid 3-arabinosides were inhibited by bagging and these compounds only re-accumulated to a small degree in the fruit peel of 'Zaosu' after the bags were removed. In contrast, the biosynthesis of flavonoid 3-gluctosides and flavonoid 3-rutinosides was reduced by bagging and then increased when the fruits were re-exposed to sunlight. A combination of correlation, multicollinearity test and partial-correlation analyses among major flavonoid metabolites indicated that biosynthesis of each phenolic compound was independent in 'Zaosu' pear, except for the positive correlation between flavonoid 3-rutincosides and flavanols. In contrast with the green pear cultivar, almost all phenolic compounds in the red mutant had similar biosynthesis patterns except for arbutin. However, only the biosynthesis of flavonoid 3-galactosides was relatively independent and strongly affected the synthesis of the other phenolic compounds. Therefore, we propose a hypothesis that the strong accumulation of flavonoid 3-galactosides stimulated the biosynthesis of other flavonoid compounds in the red mutant and, therefore, caused systemic variation of flavonoid biosynthesis profiles between 'Zaosu' and its red mutant. This hypothesis had been further demonstrated by the enzyme activity of UFGT, and transcript levels of flavonoid biosynthetic genes and been well tested by a stepwise linear regression forecasting model. The gene that encodes flavonoid 3-galacosyltransferase was also identified and isolated from the pear genome.

  2. The influence of light quality on the accumulation of flavonoids in tobacco (Nicotiana tabacum L.) leaves.

    Science.gov (United States)

    Fu, Bo; Ji, Xiaoming; Zhao, Mingqin; He, Fan; Wang, Xiaoli; Wang, Yiding; Liu, Pengfei; Niu, Lu

    2016-09-01

    Flavonoids are important secondary metabolites in plants regulated by the environment. To analyze the effect of light quality on the accumulation of flavonoids, we performed a rapid analysis of flavonoids in extracts of tobacco leaves using UHPLC-QTOF. A total of 12 flavonoids were detected and identified in tobacco leaves, which were classified into flavonoid methyl derivatives and flavonoid glycoside derivatives according to the groups linked to the flavonoid core. Correlation analysis was further conducted to investigate the effect of different wavelengths of light on their accumulation. The content of flavonoid methyl derivatives was positively correlated with the proportions of far-red light (FR; 716-810nm) and near-infrared light (NIR; 810-2200nm) in the sunlight spectrum and negatively correlated with the proportion of ultraviolet (UV-A; 350-400nm) and the red/far-red ratio (R/FR). By contrast, the content of flavonoid glycoside derivatives was positively correlated with the proportion of UV-A and the R/FR, and negatively correlated with FR and NIR. The results indicated that light quality with higher proportions of FR and NIR increases the activity of flavonoid methyltransferases but suppresses the activity of flavonoid glycoside transferases. While a high proportion of UV-A and a high R/FR can increase flavonoid glycoside transferase activity but suppress flavonoid methyltransferase activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Leishmanicidal Activity of Nine Novel Flavonoids from Delphinium staphisagria

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    Inmaculada Ramírez-Macías

    2012-01-01

    Full Text Available Objectives. To evaluate the in vitro leishmanicidal activity of nine flavonoid derivatives from Delphinium staphisagria against L. infantum and L. braziliensis. Design and Methods. The in vitro activity of compounds 1–9 was assayed on extracellular promastigote and axenic amastigote forms and on intracellular amastigote forms of the parasites. Infectivity and cytotoxicity tests were carried on J774.2 macrophage cells using Glucantime as the reference drug. The mechanisms of action were analysed performing metabolite excretion and transmission electronic microscope ultrastructural alteration studies. Results. Nine flavonoids showed leishmanicidal activity against promastigote as well as amastigote forms of Leishmania infantum and L. braziliensis. These compounds were nontoxic to mammalian cells and were effective at similar concentrations up to or lower than that of the reference drug (Glucantime. The results showed that 2″-acetylpetiolaroside (compound 8 was clearly the most active. Conclusion. This study has demonstrated that flavonoid derivatives are active against L. infantum and L. braziliensis.

  4. Buckwheat seedling flavonoids do not undergo rapid turnover

    International Nuclear Information System (INIS)

    Margna, U.; Vainjaerv, T.

    1981-01-01

    Pulse-labelling with exogenous [1- 14 C]-L-phenylalanine showed that of all flavonoids of buckwheat seedling cotyledons only anthocyanins underwent a slow turnover (not more than 6-8 per cent a day) whilst the major flavonoids, rutin and four C-glycosylflavones, remained metabolically stable within at least 7 days. From excised hypocotyls pulse-labelled flavonoids (anthocyanins and rutin) began to disappear gradually beginning with the second day of incubation. As hypocotyls, however, during prolonged incubation soon began to autolyse a considerable part of that loss was obviously due to abnormal shifts in cell metabolic activities with a possibility that some microbial process was also involved. In hypocotyls of intact seedlings pulse-labelled rutin, similar to rutin in cotyledons, showed no signs of turnover. (author)

  5. Diamond-like nanoparticles influence on flavonoids transport: molecular modelling

    Science.gov (United States)

    Plastun, Inna L.; Agandeeva, Ksenia E.; Bokarev, Andrey N.; Zenkin, Nikita S.

    2017-03-01

    Intermolecular interaction of diamond-like nanoparticles and flavonoids is investigated by numerical simulation. Using molecular modelling by the density functional theory method, we analyze hydrogen bonds formation and their influence on IR - spectra and structure of molecular complex which is formed due to interaction between flavonoids and nanodiamonds surrounded with carboxylic groups. Enriched adamantane (1,3,5,7 - adamantanetetracarboxylic acid) is used as an example of diamond-like nanoparticles. Intermolecular forces and structure of hydrogen bonds are investigated. IR - spectra and structure parameters of quercetin - adamantanetetracarboxylic acid molecular complex are obtained by numerical simulation using the Gaussian software complex. Received data coincide well with experimental results. Intermolecular interactions and hydrogen bonding structure in the obtained molecular complex are examined. Possibilities of flavonoids interaction with DNA at the molecular level are also considered.

  6. Phyto chemical study of the flavonoids of khaya senegalensis

    International Nuclear Information System (INIS)

    Shakir, S. H.

    2005-03-01

    Phyto chemical screening of the leaves of Khaya senegalensis revealed the presence of flavonoids. Crushed air-dried leaves of Khaya senegalensis were extracted at ambient temperature with ethanol. The crude product obtained after removal of the solvent was subjected to chromatographic fractionation. Using silica gel and the solvent system: butanol: acetic acid: water (3:1:6 ; V:V:V) a pure flavonoid was isolated. The colour reactions and the UV spectra of the isolated flavonoid clearly indicated that it is a flavone. The hydroxylation pattern of the isolated flavone was studies using shift reagents. The structural features were further elucidated via IR, NMR and Mass spectrophotometry. The following tentative structure was proposed.(Author)

  7. In vitro biotransformation of flavonoids by rat liver microsomes

    DEFF Research Database (Denmark)

    Nielsen, S. E.; Breinholt, V.; Justesen, U.

    1998-01-01

    1. Sixteen naturally occurring flavonoids were investigated as substrates for cytochrome P450 in uninduced and Aroclor 1254-induced rat liver microsomes. Naringenin, hesperetin, chrysin, apigenin, tangeretin, kaempferol, galangin and tamarixetin were all metabolized extensively by induced rat liver...... pathway leading to the corresponding 3',4'-dihydroxylated flavonoids either by hydroxylation or demethylation. Structural requirements for microsomal hydroxylation appeared to be a single or no hydroxy group on the B-ring of the flavan nucleus. The presence of two or more hydroxy groups on the B......-ring seemed to prevent further hydroxylation. The results indicate that demethylation only occurs in the B-ring when the methoxy group is positioned at C-4'-, and not at the C-3'-position. 3. The CYP1A isozymes were found to be the main enzymes involved in flavonoid hydroxylation, whereas other cytochrome P...

  8. Novel Investigations of Flavonoids as Chemopreventive Agents for Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Chen-Yi Liao

    2015-01-01

    Full Text Available We would like to highlight the application of natural products to hepatocellular carcinoma (HCC. We will focus on the natural products known as flavonoids, which target this disease at different stages of hepatocarcinogenesis. In spite of the use of chemotherapy and radiotherapy in treating HCC, patients with HCC still face poor prognosis because of the nature of multidrug resistance and toxicity derived from chemotherapy and radiotherapy. Flavonoids can be found in many vegetables, fruits, and herbal medicines that exert their different anticancer effects via different intracellular signaling pathways and serve as antioxidants. In this review, we will discuss seven common flavonoids that exert different biological effects against HCC via different pathways.

  9. Flavonoid electrochemistry: a review on the electroanalytical applications

    Directory of Open Access Journals (Sweden)

    Eric S. Gil

    2013-05-01

    Full Text Available Flavonoids are polyphenolic compounds widespread in vegetal kingdom. They present a C-15 skeleton, which is divided into three units A, B and C. Unit C is an oxygen containing heterocyclic, whose oxidation state and saturation level define major subclasses. Units A and B are aromatic rings, in which four major types of substituents, i. e. hydroxyl, methoxyl, prenyl and glycosides, lead to over 8000 different flavonoids. The great healthy-protecting value of these phytochemical biomarkers has attracted the attention of scientific community. Their main biological actions include anticancer and anti-inflammatory properties, which are strictly linked to antioxidant activities. So that, electroanalysis have been extensively applied on mechanistic studies and also for analytical determinations. This review presents the state of the art regarding the main applications of electroanalysis on the flavonoid research. The approaches on redox behavior characterization leading to a better understanding of structure antioxidant activity relationships are highlighted.

  10. Flavonoid electrochemistry: a review on the electroanalytical applications

    Directory of Open Access Journals (Sweden)

    Eric S. Gil

    2013-06-01

    Full Text Available Flavonoids are polyphenolic compounds widespread in vegetal kingdom. They present a C-15 skeleton, which is divided into three units A, B and C. Unit C is an oxygen containing heterocyclic, whose oxidation state and saturation level define major subclasses. Units A and B are aromatic rings, in which four major types of substituents, i. e. hydroxyl, methoxyl, prenyl and glycosides, lead to over 8000 different flavonoids. The great healthy-protecting value of these phytochemical biomarkers has attracted the attention of scientific community. Their main biological actions include anticancer and anti-inflammatory properties, which are strictly linked to antioxidant activities. So that, electroanalysis have been extensively applied on mechanistic studies and also for analytical determinations. This review presents the state of the art regarding the main applications of electroanalysis on the flavonoid research. The approaches on redox behavior characterization leading to a better understanding of structure antioxidant activity relationships are highlighted.

  11. Determination of Flavonoids in Wine by High Performance Liquid Chromatography

    Science.gov (United States)

    da Queija, Celeste; Queirós, M. A.; Rodrigues, Ligia M.

    2001-02-01

    The experiment presented is an application of HPLC to the analysis of flavonoids in wines, designed for students of instrumental methods. It is done in two successive 4-hour laboratory sessions. While the hydrolysis of the wines is in progress, the students prepare the calibration curves with standard solutions of flavonoids and calculate the regression lines and correlation coefficients. During the second session they analyze the hydrolyzed wine samples and calculate the concentrations of the flavonoids using the calibration curves obtained earlier. This laboratory work is very attractive to students because they deal with a common daily product whose components are reported to have preventive and therapeutic effects. Furthermore, students can execute preparative work and apply a more elaborate technique that is nowadays an indispensable tool in instrumental analysis.

  12. Flavonoid rutin increases thyroid iodide uptake in rats.

    Directory of Open Access Journals (Sweden)

    Carlos Frederico Lima Gonçalves

    Full Text Available Thyroid iodide uptake through the sodium-iodide symporter (NIS is not only an essential step for thyroid hormones biosynthesis, but also fundamental for the diagnosis and treatment of different thyroid diseases. However, part of patients with thyroid cancer is refractory to radioiodine therapy, due to reduced ability to uptake iodide, which greatly reduces the chances of survival. Therefore, compounds able to increase thyroid iodide uptake are of great interest. It has been shown that some flavonoids are able to increase iodide uptake and NIS expression in vitro, however, data in vivo are lacking. Flavonoids are polyhydroxyphenolic compounds, found in vegetables present in human diet, and have been shown not only to modulate NIS, but also thyroperoxidase (TPO, the key enzyme in thyroid hormones biosynthesis, besides having antiproliferative effect in thyroid cancer cell lines. Therefore, we aimed to evaluate the effect of some flavonoids on thyroid iodide uptake in Wistar rats in vivo. Among the flavonoids tested, rutin was the only one able to increase thyroid iodide uptake, so we decided to evaluate the effect of this flavonoid on some aspects of thyroid hormones synthesis and metabolism. Rutin led to a slight reduction of serum T4 and T3 without changes in serum thyrotropin (TSH, and significantly increased hypothalamic, pituitary and brown adipose tissue type 2 deiodinase and decreased liver type 1 deiodinase activities. Moreover, rutin treatment increased thyroid iodide uptake probably due to the increment of NIS expression, which might be secondary to increased response to TSH, since TSH receptor expression was increased. Thus, rutin might be useful as an adjuvant in radioiodine therapy, since this flavonoid increased thyroid iodide uptake without greatly affecting thyroid function.

  13. Dietary PUFA and flavonoids as deterrents for environmental pollutants.

    Science.gov (United States)

    Watkins, Bruce A; Hannon, Kevin; Ferruzzi, Mario; Li, Yong

    2007-03-01

    Various nutrients and plant-derived phytochemicals are associated with a reduced risk of many diet-related chronic diseases including cardiovascular disease, cancer, diabetes, arthritis and osteoporosis. A common theme that links many chronic diseases is uncontrolled inflammation. The long-chain (LC) omega-3 polyunsaturated fatty acids (PUFA) and flavonoids are known to possess anti-inflammatory actions in cell cultures, animal models and humans. Minimizing the condition of persistent inflammation has been a primary aim for drug development, but understanding how food components attenuate this process is at the nexus for improving the human condition. The prevalence of environmental toxins such as heavy metals and organics that contribute to diminished levels of antioxidants likely aggravates inflammatory states when intakes of omega-3 PUFA and flavonoids are marginal. Scientists at Purdue University have formed a collaboration to better understand the metabolism and physiology of flavonoids. This new effort is focused on determining how candidate flavonoids and their metabolites affect gene targets of inflammation in cell culture and animal models. The challenge of this research is to understand how LC omega-3 PUFA and flavonoids affect the biology of inflammation. The goal is to determine how nutrients and phytochemicals attenuate chronic inflammation associated with a number of diet-related diseases that occur throughout the life cycle. The experimental approach involves molecular, biochemical and physiological endpoints of aging, cancer, obesity and musculoskeletal diseases. Examples include investigations on the combined effects of PUFA and cyanidins on inflammatory markers in cultures of human cancer cells. The actions of catechins and PUFA on muscle loss and osteopenia are being studied in a rodent model of disuse atrophy to explain how muscle and bone communicate to prevent tissue loss associated with injury, disease and aging. The purpose of this review is

  14. Quantitative determination of sage-leaved rockrose (Cistus salviifolius flavonoids

    Directory of Open Access Journals (Sweden)

    H. M. Elkaib

    2017-01-01

    Full Text Available The widespread use of bioflavonoids, due to their antimicrobial activity and antioxidant properties, necessitates their separate determination in a joint presence. It is noted that the total content of flavonoids, determined by different spectrophotometric methods in the same samples, differs and depends on the structure of the individual flavonoids that make up the samples. The paper presents the results of studies to determine the content of flavonoids in the fraction of the dry extract of shalfeeloid canthus (Cistus salviifolius, which has antimicrobial activity against bacteria of the genus Pseudomonas, which causes damage to protein-containing food products. Curing flavonoids by sequential extraction with aqueous alcohol solutions, filtering and dissolving the dry residue in isopropyl alcohol followed by passing through the gel layers. The following methods for the determination of flavonoids are considered: reaction with Folin-Chikalteu reagent (using quercetin as standard, reaction with aluminum chloride and 2,4-dinitrophenylhydrazine. When oxidized in alkaline medium by the Folin-Chikalteu reagent, which is the phospho-molybdotungstate heteropolycomplexes of flavonols, flavin-3-ol and flavones can be converted into quinoid compounds having absorption bands in the visible region of the spectrum. Only flavones and flavones having hydroxyl groups at positions 3 and 5 can interact with AlCl3. 2,4-dinitrophenylhydrazine only interacts with flavonols. The obtained calibration curves and structural formulas of flavonoids are given, which can be determined by the methods presented. It was found to contain flavonols 0.21 mg / mg, flavones 0.17 mg / mg and flavin-3-ol 0.06 mg/mg.

  15. Flavonoids and a neolignan glucoside from Guarea macrophylla (Meliaceae)

    International Nuclear Information System (INIS)

    Pereira, Cristiane; Barreto Junior, Cleber Bomfim; Kuster, Ricardo Machado; Simas, Naomi Kato; Sakuragui, Cassia Monica; Porzel, Andrea; Wessjohann, Ludger

    2012-01-01

    This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside) and a neolignan glucoside, dehydrodiconiferyl alcohol-4-b-D-glucoside. All compounds were identified by a combination of spectroscopic methods ( 1 H, 1D, 2D NMR, 13 C and UV), ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family. (author)

  16. Dietary flavonoid intake at midlife and healthy aging in women.

    Science.gov (United States)

    Samieri, Cécilia; Sun, Qi; Townsend, Mary K; Rimm, Eric B; Grodstein, Francine

    2014-12-01

    Dietary flavonoids have been related to lower risks of various chronic diseases, but it is unclear whether flavonoid intake in midlife helps to maintain good health and wellbeing in aging. We examined the relation of flavonoid intake in midlife with the prevalence of healthy aging. We included 13,818 women from the Nurses' Health Study with dietary data and no major chronic diseases in 1984-1986 when they were aged in their late 50s (median age: 59 y); all women provided information on multiple aspects of aging an average of 15 y later. Intakes of 6 major flavonoid subclasses in midlife were ascertained on the basis of averaged intakes of flavonoid-rich foods from 2 food-frequency questionnaires (1984-1986). We defined healthy compared with usual aging as of age 70 y; healthy aging was based on survival to ≥70 y with maintenance of 4 health domains (no major chronic diseases or major impairments in cognitive or physical function or mental health). Of women who survived until ≥70 y of age, 1517 women (11.0%) met our criteria for healthy aging. Compared with women in the lowest quintile of intake, women in the highest quintile of intake of several flavonoid subclasses at midlife had greater odds of healthy aging. After multivariable adjustment, ORs were as follows: flavones, 1.32 (95% CI: 1.10, 1.58); flavanone, 1.28 (95% CI: 1.08, 1.53); anthocyanin, 1.25 (95% CI: 1.04, 1.50); and flavonol, 1.18 (95% CI: 0.98, 1.42) (all P-trend ≤ 0.02). Consistently, greater intakes of major sources of these flavonoids (i.e., oranges, berries, onions, and apples) were associated with increased odds of healthy aging. We showed no association with flavan-3-ol monomers (P-trend = 0.80) or polymers (P-trend = 0.63). Higher intake of flavonoids at midlife, specifically flavones, flavanones, anthocyanins, and flavonols, is associated with greater likelihood of health and wellbeing in individuals surviving to older ages. © 2014 American Society for Nutrition.

  17. Triterpenes and flavonoids from the roots of Mauritia flexuosa

    Directory of Open Access Journals (Sweden)

    Hector H. F. Koolen

    2011-11-01

    Full Text Available Mauritia flexuosa L. f., Arecaceae, is an endemic species of South America. This species was studied with the intent to isolate the constituents of its roots. After the fractionation of the n-hexane and methanolic extracts from the roots of M. flexuosa, six triterpenes were obtained: friedelin, taraxerone, lupenyl acetate, lupenone, betulin and betulinic acid, along with three flavonoids: rutin, quercitrin and quercetin. All the compounds were identified by analysis of NMR and MS data and comparison with the literature. All those compounds are been reported for the first time in Mauritia, and the chemosystematic significance of the flavonoids isolated in this genus is discussed.

  18. Triterpenes and flavonoids from the roots of Mauritia flexuosa

    Directory of Open Access Journals (Sweden)

    Hector H. F. Koolen

    2012-02-01

    Full Text Available Mauritia flexuosa L. f., Arecaceae, is an endemic species of South America. This species was studied with the intent to isolate the constituents of its roots. After the fractionation of the n-hexane and methanolic extracts from the roots of M. flexuosa, six triterpenes were obtained: friedelin, taraxerone, lupenyl acetate, lupenone, betulin and betulinic acid, along with three flavonoids: rutin, quercitrin and quercetin. All the compounds were identified by analysis of NMR and MS data and comparison with the literature. All those compounds are been reported for the first time in Mauritia, and the chemosystematic significance of the flavonoids isolated in this genus is discussed.

  19. Dirhamnosyl flavonoid and other constituents from Brillantaisia palisatii

    Energy Technology Data Exchange (ETDEWEB)

    Berrondo, Luciane Fatima; Gabriel, Felipe Teixeira; Fernandes, Sidney Bessa de; Menezes, Fabio de Sousa [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Farmacia. Dept. de Produtos Naturais e Alimentos]. E-mail: fsmenezes@pharma.ufrj.br; Moreira, Davyson de Lima [Universidade de Barra Mansa, RJ (Brazil). Faculdade de Farmacia

    2003-12-01

    A mixture containing sitosterol and stigmasterol; a new triterpene 3-epi-ursolic acid; another triterpene mixture comprising {alpha}-amyrin, {beta}-amyrin and lupeol; verbascoside, a phenylpropanoid glycoside; and lespedin, a glycosyl flavonoid, were isolated. The less polar compounds (steroids and triterpenoids) were isolated from the hexane partition of the crude ethanolic extract while the more polar ones (phenylpropanoid glycoside and glycosyl flavonoid) were isolated from the ethyl acetate partition of the same extract. The structures of all compounds were established using modern spectrometric methods of elucidation. The spectroscopic data of Lespedin, a rare dirhamnosylflavonol with hypotensor activity and of the triterpene, 3-epi-ursolic acid, are also reported. (author)

  20. Primula latifolia Lapeyr. and Primula vulgaris Hudson flavonoids.

    Science.gov (United States)

    Colombo, Paola S; Flamini, Guido; Fico, Gelsomina

    2014-01-01

    Three flavonoids were isolated from the leaf MeOH extracts of Primula latifolia Lapeyr. and Primula vulgaris Hudson collected from Italian Alps: rutin (1) and kaempferol 3-neohesperidoside (2) from P. latifolia, and kaempferol 3-β-O-glucopyranosyl-(1 → 2) gentiobioside (3) from P. vulgaris. The structures were assigned on the basis of their (1)H and (13)C NMR data, including those derived from 2D NMR, as well as on HPLC-MS results. This article is the first to report on P. vulgaris tissue flavonoids after Harborne's study in 1968 and the first work ever on these compounds from P. latifolia.

  1. Flavonoids and a neolignan glucoside from Guarea macrophylla (Meliaceae

    Directory of Open Access Journals (Sweden)

    Cristiane Pereira

    2012-01-01

    Full Text Available This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside and a neolignan glucoside, dehydrodiconiferyl alcohol-4-β-D-glucoside. All compounds were identified by a combination of spectroscopic methods (¹H, 1D, 2D NMR, 13C and UV, ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family.

  2. Effects of dietary flavonoids intake in Saudi patients with coronary heart disease

    Directory of Open Access Journals (Sweden)

    Mohammed A Alsaif

    2007-01-01

    Conclusions: The findings of the study support a potential protective effect of dietary flavonoids in relation to CHD. The study showed that consuming more Flavonoids may have positive effect on lowering blood lipids.

  3. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy.

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P; Nguyen, Huong T H; Dang, Andy; Tureček, František

    2018-01-16

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z 4 + H] +● fragment ion-radicals of the R-C ● H-CONH- type, initially formed by N-C α bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [ ● DAAR + H] + isomers and used to assign structures to the action spectra. The potential energy surface of [ ● DAAR + H] + isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [ ● XAAR + H] + ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone C α positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H] ● -ETD fragments containing Asp, Asn, Glu, and Gln residues. Graphical Abstract ᅟ.

  4. A system to measure isomeric state half-lives in the 10 ns to 10 μs range

    Energy Technology Data Exchange (ETDEWEB)

    Toufen, D. L., E-mail: dennis@if.usp.br [Institute of Physics, University of São Paulo, C.P. 66318, 05315-970 São Paulo, São Paulo (Brazil); Federal Institute of Education, Science and Technology of São Paulo - IFSP, 07115-000 Guarulhos, São Paulo (Brazil); Allegro, P. R. P.; Medina, N. H.; Oliveira, J. R. B.; Cybulska, E. W.; Seale, W. A.; Ribas, R. V. [Institute of Physics, University of São Paulo, C.P. 66318, 05315-970 São Paulo, São Paulo (Brazil); Linares, R. [Fluminense Federal University, 24220-900 Niterói, Rio de Janeiro (Brazil); Silveira, M. A. G. [Universitary Center of FEI, 09850-901 São Bernardo do Campo, São Paulo (Brazil)

    2014-07-15

    The Isomeric State Measurement System (SISMEI) was developed to search for isomeric nuclear states produced by fusion-evaporation reactions. The SISMEI consists of 10 plastic phoswich telescopes, two lead shields, one NaI(Tl) scintillation detector, two Compton suppressed HPGe γ-ray detectors, and a cone with a recoil product catcher. The new system was tested at the 8 UD Pelletron tandem accelerator of the University of São Paulo with the measurement of two known isomeric states: {sup 54}Fe, 10{sup +} state (E = 6527.1 (11) keV, T{sub 1/2} = 364(7) ns) and the 5/2{sup +} state of {sup 19}F (E = 197.143 (4) keV, T{sub 1/2} = 89.3 (10) ns). The results indicate that the system is capable of identifying delayed transitions, of measuring isomeric state lifetimes, and of identifying the feeding transitions of the isomeric state through the delayed γ-γ coincidence method. The measured half-life for the 10{sup +} state was T{sub 1/2} = 365(14) ns and for the 5/2{sup +} state, 100(36) ns.

  5. A system to measure isomeric state half-lives in the 10 ns to 10 μs range

    Science.gov (United States)

    Toufen, D. L.; Allegro, P. R. P.; Medina, N. H.; Oliveira, J. R. B.; Cybulska, E. W.; Seale, W. A.; Linares, R.; Silveira, M. A. G.; Ribas, R. V.

    2014-07-01

    The Isomeric State Measurement System (SISMEI) was developed to search for isomeric nuclear states produced by fusion-evaporation reactions. The SISMEI consists of 10 plastic phoswich telescopes, two lead shields, one NaI(Tl) scintillation detector, two Compton suppressed HPGe γ-ray detectors, and a cone with a recoil product catcher. The new system was tested at the 8 UD Pelletron tandem accelerator of the University of São Paulo with the measurement of two known isomeric states: 54Fe, 10+ state (E = 6527.1 (11) keV, T1/2 = 364(7) ns) and the 5/2+ state of 19F (E = 197.143 (4) keV, T1/2 = 89.3 (10) ns). The results indicate that the system is capable of identifying delayed transitions, of measuring isomeric state lifetimes, and of identifying the feeding transitions of the isomeric state through the delayed γ-γ coincidence method. The measured half-life for the 10+ state was T1/2 = 365(14) ns and for the 5/2+ state, 100(36) ns.

  6. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P.; Nguyen, Huong T. H.; Dang, Andy; Tureček, František

    2018-01-01

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z4 + H]+● fragment ion-radicals of the R-C●H-CONH- type, initially formed by N-Cα bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [●DAAR + H]+ isomers and used to assign structures to the action spectra. The potential energy surface of [●DAAR + H]+ isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [●XAAR + H]+ ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone Cα positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H]●-ETD fragments containing Asp, Asn, Glu, and Gln residues. [Figure not available: see fulltext.

  7. Composition of flavonoids in fresh herbs and calculation of flavonoid intake by use of herbs in traditional Danish dishes

    DEFF Research Database (Denmark)

    Justesen, U.; Knuthsen, Pia

    2001-01-01

    , coriander, cress, dill, lemon balm, lovage, oregano, parsley, rosemary, sage, spearmint, tarragon, thyme, and watercress) were analysed by HPLC and mass spectrometry. Five major flavonoid aglycones were detected and quantified by HPLC after acid hydrolysis: apigenin, isorhamnetin, kaempferol, luteolin......Many herbs are known as excellent sources of natural antioxidants, and consumption of fresh herbs in the diet may therefore contribute to the daily antioxidant intake. The present study was performed in order to quantify flavonoids in commonly eaten fresh herbs. Fifteen fresh herbs (basil, chives......, and quercetin. The highest levels of flavonoids were found in parsley (510-630 mg apigenin /100 g), lovage (170 mg quercetin/100g), mint (18-100 mg apigenin/ 100 g), and dill (48-110 mg quercetin/100 g). Mass spectrometric detection, using atmospheric pressure chemical ionisation (APCI), was used to verify...

  8. A comprehensive mechanistic picture of the isomerizing alkoxycarbonylation of plant oils

    KAUST Repository

    Roesle, Philipp

    2014-12-03

    Theoretical studies on the overall catalytic cycle of isomerizing alkoxycarbonylation reveal the steric congestion around the diphosphine coordinated Pd-center as decisive for selectivity and productivity. The energy profile of isomerization is flat with diphosphines of variable steric bulk, but the preference for the formation of the linear Pd-alkyl species is more pronounced with sterically demanding diphosphines. CO insertion is feasible and reversible for all Pd-alkyl species studied and only little affected by the diphosphine. The overall rate-limiting step associated with the highest energetic barrier is methanolysis of the Pd-acyl species. Considering methanolysis of the linear Pd-acyl species, whose energetic barrier is lowest within all the Pd-acyl species studied, the barrier is calculated to be lower for more congesting diphosphines. Calculations indicate that energy differences of methanolysis of the linear versus branched Pd-acyls are more pronounced for more bulky diphosphines, due to involvement of different numbers of methanol molecules in the transition state. Experimental studies under pressure reactor conditions showed a faster conversion of shorter chain olefin substrates, but virtually no effect of the double bond position within the substrate. Compared to higher olefins, ethylene carbonylation under identical conditions is much faster, likely due not just to the occurrence of reactive linear acyls exclusively but also to an intrinsically favorable insertion reactivity of the olefin. The alcoholysis reaction is slowed down for higher alcohols, evidenced by pressure reactor and NMR studies. Multiple unsaturated fatty acids were observed to form a terminal Pd-allyl species upon reaction with the catalytically active Pd-hydride species. This process and further carbonylation are slow compared to isomerizing methoxycarbonylation of monounsaturated fatty acids, but selective.

  9. A comprehensive mechanistic picture of the isomerizing alkoxycarbonylation of plant oils.

    Science.gov (United States)

    Roesle, Philipp; Caporaso, Lucia; Schnitte, Manuel; Goldbach, Verena; Cavallo, Luigi; Mecking, Stefan

    2014-12-03

    Theoretical studies on the overall catalytic cycle of isomerizing alkoxycarbonylation reveal the steric congestion around the diphosphine coordinated Pd-center as decisive for selectivity and productivity. The energy profile of isomerization is flat with diphosphines of variable steric bulk, but the preference for the formation of the linear Pd-alkyl species is more pronounced with sterically demanding diphosphines. CO insertion is feasible and reversible for all Pd-alkyl species studied and only little affected by the diphosphine. The overall rate-limiting step associated with the highest energetic barrier is methanolysis of the Pd-acyl species. Considering methanolysis of the linear Pd-acyl species, whose energetic barrier is lowest within all the Pd-acyl species studied, the barrier is calculated to be lower for more congesting diphosphines. Calculations indicate that energy differences of methanolysis of the linear versus branched Pd-acyls are more pronounced for more bulky diphosphines, due to involvement of different numbers of methanol molecules in the transition state. Experimental studies under pressure reactor conditions showed a faster conversion of shorter chain olefin substrates, but virtually no effect of the double bond position within the substrate. Compared to higher olefins, ethylene carbonylation under identical conditions is much faster, likely due not just to the occurrence of reactive linear acyls exclusively but also to an intrinsically favorable insertion reactivity of the olefin. The alcoholysis reaction is slowed down for higher alcohols, evidenced by pressure reactor and NMR studies. Multiple unsaturated fatty acids were observed to form a terminal Pd-allyl species upon reaction with the catalytically active Pd-hydride species. This process and further carbonylation are slow compared to isomerizing methoxycarbonylation of monounsaturated fatty acids, but selective.

  10. Positionally isomeric organic gelators: structure-gelation study, racemic versus enantiomeric gelators, and solvation effects.

    Science.gov (United States)

    Caplar, Vesna; Frkanec, Leo; Sijaković Vujicić, Natasa; Zinić, Mladen

    2010-03-08

    Low molecular weight gelator molecules consisting of aliphatic acid, amino acid (phenylglycine), and omega-aminoaliphatic acid units have been designed. By varying the number of methylene units in the aliphatic and omega-aminoaliphatic acid chains, as defined by descriptors m and n, respectively, a series of positionally isomeric gelators having different positions of the peptidic hydrogen-bonding unit within the gelator molecule has been obtained. The gelation properties of the positional isomers have been determined in relation to a defined set of twenty solvents of different structure and polarity and analyzed in terms of gelator versatility (G(ver)) and effectiveness (G(eff)). The results of gelation tests have shown that simple synthetic optimizations of a "lead gelator molecule" by variation of m and n, end-group polarity (carboxylic acid versus sodium carboxylate), and stereochemistry (racemate versus optically pure form) allowed the identification of gelators with tremendously improved versatility (G(ver)) and effectiveness (G(eff)). Dramatic differences in G(eff) values of up to 70 times could be observed between pure racemate/enantiomer pairs of some gelators, which were manifested even in the gelation of very similar solvents such as isomeric xylenes. The combined results of spectroscopic ((1)H NMR, FTIR), electron microscopy (TEM), and X-ray diffraction studies suggest similar organization of the positionally isomeric gelators at the molecular level, comprising parallel beta-sheet hydrogen-bonded primary assemblies that form inversed bilayers at a higher organizational level. Differential scanning calorimetry (DSC) studies of selected enantiomer/racemate gelator pairs and their o- and p-xylene gels revealed the simultaneous presence of different polymorphs in the racemate gels. The increased gelation effectiveness of the racemate compared to that of the single enantiomer is most likely a consequence of its spontaneous resolution into enantiomeric

  11. Outcomes following the Kawashima procedure for single-ventricle palliation in left atrial isomerism.

    Science.gov (United States)

    Vollebregt, Anne; Pushparajah, Kuberan; Rizvi, Maleeha; Hoschtitzky, Andreas; Anderson, David; Austin, Conal; Tibby, Shane M; Simpson, John

    2012-03-01

    Patients with left atrial isomerism and interrupted inferior vena cava palliated with a superior cavopulmonary connection or Kawashima procedure (KP) have a high incidence of developing pulmonary arteriovenous malformations. The necessity for hepatic vein redirection (HVR) and its timing remains a controversy. We aimed to assess the clinical outcome of patients with left atrial isomerism following a KP. The main end points were death, requirement for HVR and the impact of HVR on oxygen saturation. Retrospective review of 21 patients with a diagnosis of left atrial isomerism, interruption of the inferior vena cava and single-ventricle physiology managed with a KP at a single centre between January 1990 and March 2010. Twenty-one patients had a KP, with 12 subsequently undergoing HVR. There was relatively a constant monthly decrement in the proportion of patients who were free from death or HVR up until 60 months following the KP, with a dramatic increase in the hazard after this time. The Cox proportional hazards regression model demonstrated a reduced early risk for HVR or death in patients who underwent pulmonary artery banding versus arterial shunt as the primary procedure (hazard ratio: 0.10; P = 0.01), and an increased risk with bilateral superior vena cavas (SVCs) (hazard ratio: 3.4; P = 0.04) and age at KP (hazard ratio: 1.02 per month increase in age at KP; P = 0.02). HVR mortality was relatively high with 3 of 12 patients dying in the early postoperative period with profound cyanosis. The timing of HVR after the KP did not influence the postoperative rate of increase in oxygen saturation. These findings confirm that the majority of patients who undergo a KP will require HVR. Patients who are older at the time of the KP or having an initial arterial shunt or bilateral SVCs are at higher risk of HVR or death. The relatively high mortality at HVR was characterized by severe postoperative cyanosis.

  12. Dipole-resonance assisted isomerization in the electronic ground state using few-cycle infrared pulses.

    Science.gov (United States)

    Skocek, Oliver; Uiberacker, Christoph; Jakubetz, Werner

    2011-06-30

    A computational investigation of HCN → HNC isomerization in the electronic ground state by one- and few-cycle infrared pulses is presented. Starting from a vibrationally pre-excited reagent state, isomerization yields of more than 50% are obtained using single one- to five-cycle pulses. The principal mechanism includes two steps of population transfer by dipole-resonance (DR), and hence, the success of the method is closely linked to the polarity of the system and, in particular, the stepwise change of the dipole moment from reactant to transition state and on to products. The yield drops massively if the diagonal dipole matrix elements are artificially set to zero. In detail, the mechanism includes DR-induced preparation of a delocalized vibrational wavepacket, which traverses the barrier region and is finally trapped in the product well by DR-dominated de-excitation. The excitation and de-excitation steps are triggered by pulse lobes of opposite field direction. As the number of optical cycles is increased, the leading field lobes prepare a vibrational superposition state by off-resonant ladder climbing, which is then subjected to the three steps of the principal isomerization mechanism. DR excitation is more efficient from a preformed vibrational wavepacket than from a molecular eigenstate. The entire process can be loosely described as Tannor-Kosloff-Rice type transfer mechanism on a single potential surface effected by a single pulse, individual field lobes assuming the roles of pump- and dump-pulses. Pre-excitation to a transient wavepacket can be enhanced by applying a separate, comparatively weak few-cycle prepulse, in which the prepulse prepares a vibrational wavepacket. The two-pulse setup corresponds to a double Tannor-Kosloff-Rice control scheme on a single potential surface.

  13. Physico-chemical study of flavonoids from different matureness corn silk material

    OpenAIRE

    Li, Peng; Lapčík, Lubomír; Lapčíková, Barbora; Kalytchuk, Sergii

    2018-01-01

    There was tested a simple extraction procedure of flavonoids separation from the original corn silk (CS) material. It was found, that the total flavonoids content differs with the extraction time and extraction temperature. There were found different flavonoids contents in extracts prepared from different maturity stages of the original corn silk material (silking stage (CS-S), milky stage (CS-M)). Extracted flavonoids content was quantified by the lutin standardization method by means of col...

  14. Changes in flavonoid content of grapefruit juice caused by thermal treatment and storage

    OpenAIRE

    Igual Ramo, Marta; García Martínez, Eva María; Camacho Vidal, Mª Mar; Martínez Navarrete, Nuria

    2011-01-01

    The effect of conventional and microwave pasteurization on the main flavonoids present in grapefruit juice and their stability throughout 2 months of refrigerated and frozen storage was evaluated. Individual flavonoids were analyzed by HPLC. The results showed that naringin, narirutin, quercetin and naringenin were the most abundant flavonoids in grapefruit juice. In general, although every pasteurization treatment caused a significant reduction in the content of all the studied flavonoids, t...

  15. Abnormal radioactive decays out of long-lived super- and hyper-deformed isomeric states

    International Nuclear Information System (INIS)

    Marinov, A.; Gelberg, S.; Kolb, D.

    2000-01-01

    Complete text of publication follows. Recently (1-3) long-lived isomeric states have been found in the super- and hyper-deformed wells of the potential. These isomers manifested themselves by abnormal particle decays. An isomeric state in the superdeformed well of the potential in the parent nucleus can decay by very enhanced α-particle groups to superdeformed states in the daughter (1) or by very retarded α-particles (3) and also by protons (2) to normal states in the daughters. Similarly an isomeric state in the hyper-deformed well may decay by very retarded α-particle groups to superdeformed states (3), or by very enhanced α-groups to hyper-deformed states in the daughter nucleus (4). All these very unusual decay modes have been observed experimentally (1-4). For instance, a very high energy α-group of 8.6 MeV with 40d ≤ t 1/2 ≤ 2y (retardation factor of ∼10 13 ) has been observed in 195 Hg and interpreted as a III min → II min α-transition (3). Likewise, relatively low-energy and very enhanced α-particle groups (enhancement factors of 10 5 to 10 7 ) have been seen in several actinide sources and interpreted as due to II min → II min and III min → III min transitions (4). These unusual decay modes introduce new considerations in the study of heavy and superheavy elements. For instance, if low-energy α-particle groups around 4.4 - 4.6 MeV have been seen in nature (5), they may be interpreted as due to very enhanced III min → III min transitions in the superheavy element region around Z = 108 (eka-Os) with t 1/2 ∼10 8 y rather than ∼10 15 y as expected for normal α-transitions of such energies in this region, or due to very retarded III min → II min or II min → I min decays in nuclei around Os itself. In both cases, if such activities have been seen in nature, they indicate that the existence of the II min and III min isomeric states may be important in the nucleosynthesis process. It should be mentioned that long-lived high

  16. Cascade olefin isomerization/intramolecular Diels-Alder reaction catalyzed by N-heterocyclic carbenes.

    Science.gov (United States)

    Kowalczyk, Marcin; Lupton, David W

    2014-05-19

    The addition of an N-heterocyclic carbene to the carbonyl group of an α,β,γ,δ-unsaturated enol ester affords a hemiacetal azolium intermediate that enables a cascade olefin isomerization/Diels-Alder reaction, for which mechanistic studies implicate Lewis base catalysis. Preliminary studies into the utility of the products have been undertaken with reductive and oxidative cleavage, giving materials for potential use in complex-target synthesis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Modelling of tracer-kinetic results using xylene isomerization as an example

    International Nuclear Information System (INIS)

    Bauer, F.J.; Dermietzel, J.; Roesseler, M.; Koch, H.

    1976-01-01

    The analysis of results from differential or/and integral reactor experiments often admits the interpretation of a chemical reaction in several ways. In addition, the use of mathematical methods for the model selection and planning of experiments is rendered more difficult by great confidence intervals of the ascertained model parameters. The application of radioactively labelled molecules results in improving the knowledge of reaction mechanisms as well as the assessment of parameters obtained. This is shown on the basis of modelling the isomerization of xylene. (author)

  18. Macrocyclic effects upon isomeric Cu M and M Cu cores. Formation ...

    Indian Academy of Sciences (India)

    Administrator

    from the iminic site to the aminic site in the synthesis of 10 is explained by ... Our previous studies suggest that isomeric MIICuII ... Calcd. for C24H27Br2ClCuN4NiO8: C 35⋅28; H 3⋅33; N 6⋅86; Cu 7⋅78; Ni .... Electronic absorption spectra in .... 3. 1497(1). 1452. ⋅3(5). 2992(1). 1860(2). 3206(1). Z. 2. 2. 4. 2. 4. D calcd. /g.

  19. Isotope exchange study of nickel xanthate in presence of aniline and isomeric toluidines

    International Nuclear Information System (INIS)

    Naidu, G.R.K.; Naidu, P.R.

    1982-01-01

    Isotopic exchange behaviour of nickel xanthate is studied in the presence of aniline and three isomeric toluidines at 18degC. The effect of base concentration is also studied on the exchange rate. The results show that the complex is labile in the kinetic sense in the presence of aniline meta and para toluidines. The rate of exchange increases with and para toluidines. The rate of exchange increases with increase in concentration of the base. The complex displays inert behaviour in the presence of o-toluidine and it is ascribed to dominant steric effect. (author)

  20. Magnetic dipole moments of High-K isomeric states in Hf isotopes

    CERN Multimedia

    Walters, W; Nishimura, K; Bingham, C R

    2007-01-01

    It is proposed to make precision measurements of the magnetic moments of 5 multi-quasi-particle K-isomers in Hf nuclei by the Nuclear Magnetic Resonance of Oriented Nuclei (NMR/ON) technique using the NICOLE on-line nuclear orientation facility and exploiting the unique HfF$_{3}$ beams recently available at ISOLDE. Results will be used to extract single-particle and collective g-factors of the isomeric states and their excitations and to shed new light on their structure.

  1. β decay and isomeric properties of neutron-rich Ca and Sc isotopes

    International Nuclear Information System (INIS)

    Crawford, H. L.; Mantica, P. F.; Berryman, J. S.; Stoker, J. B.; Janssens, R. V. F.; Carpenter, M. P.; Kay, B. P.; Lauritsen, T.; Zhu, S.; Broda, R.; Cieplicka, N.; Fornal, B.; Grinyer, G. F.; Minamisono, K.; Hoteling, N.; Stefanescu, I.; Walters, W. B.

    2010-01-01

    The isomeric and β-decay properties of neutron-rich 53-57 Sc and 53,54 Ca nuclei near neutron number N=32 are reported, and the low-energy level schemes of 53,54,56 Sc and 53-57 Ti are presented. The low-energy level structures of the 21 Sc isotopes are discussed in terms of the coupling of the valence 1f 7/2 proton to states in the corresponding 20 Ca cores. Implications with respect to the robustness of the N=32 subshell closure are discussed, as well as the repercussions for a possible N=34 subshell closure.

  2. Quantum control of isomerization by robust navigation in the energy spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Murgida, G. E., E-mail: murgida@tandar.cnea.gov.ar [Centro Atómico Constituyentes, GIyA, CNEA, San Martín, and Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Buenos Aires (Argentina); Arranz, F. J., E-mail: fj.arranz@upm.es [Grupo de Sistemas Complejos, Universidad Politécnica de Madrid, 28040 Madrid (Spain); Borondo, F., E-mail: f.borondo@uam.es [Departamento de Química, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Instituto de Ciencias Matemáticas (ICMAT), Cantoblanco, 28049 Madrid (Spain)

    2015-12-07

    In this paper, we present a detailed study on the application of the quantum control technique of navigation in the energy spectrum to chemical isomerization processes, namely, CN–Li⇆ Li–CN. This technique is based on the controlled time variation of a Hamiltonian parameter, an external uniform electric field in our case. The main result of our work establishes that the navigation involved in the method is robust, in the sense that quite sizable deviations from a pre-established control parameter time profile can be introduced and still get good final results. This is specially relevant thinking of a experimental implementation of the method.

  3. Isomeric N-Annulated Perylene Diimide Dimers for Organic Solar Cells.

    Science.gov (United States)

    Ma, Zetong; Fu, Huiting; Meng, Dong; Jiang, Wei; Sun, Yanming; Wang, Zhaohui

    2018-04-16

    Two isomeric N-annulated perylene diimide dimers, namely, p-BDNP and m-BDNP were designed and synthesized via geometric tuning. The distinct molecular geometry and packing arrangements of isomers with almost identical optical and electrochemical properties rendered us an in-depth understanding of the molecular structure-aggregation state-photovoltaic performance relationship. Blended with the commercially available donor PCE-10, p-BDNP and m-BDNP showed distinct differences in photovoltaic performance with power conversion efficiencies (PCEs) of 5.01 % and 4.15 %, respectively. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. g-factor of the 7- isomeric state in 128Ba

    International Nuclear Information System (INIS)

    Kaur, J.; Bansal, N.; Bhati, A.K.; Sharma, V.R.; Kumar, H.; Kumar, R.; Bhowmik, R.K.; Kumar, V.

    2014-01-01

    The time differential perturbed angular distribution technique (TDPAD) has been used to measure the g-factor of the 2396 keV, 7 - isomeric state in 128 Ba. The measured value of g(7 - ) is 1.21 ± 0.01. This value is about 80% higher than the value for the expected configuration of the state and also different in sign. This clearly shows that the configuration of the state does not correspond to the pure two quasineutron configuration that was assigned to it through previous results of in-beam γ-ray spectroscopy

  5. Anesthetic implications of total anomalous systemic venous connection to left atrium with left isomerism

    Directory of Open Access Journals (Sweden)

    Parimala Prasanna Simha

    2012-01-01

    Full Text Available Total anomalous systemic venous connection (TASVC to the left atrium (LA is a rare congenital anomaly. An 11-year-old girl presented with complaints of palpitations and cyanosis. TASVC with left isomerism and noncompaction of LV was diagnosed after contrast echocardiogram and computed tomography angiogram. The knowledge of anatomy and pathophysiology is essential for the successful management of these cases. Anesthetic concerns in this case were polycythemia, paradoxical embolism and rhythm abnormalities. The patient was successfully operated by rerouting the systemic venous connection to the right atrium.

  6. Behavior of the excited deformed band and search for shape isomerism in 184Hg

    International Nuclear Information System (INIS)

    Cole, J.D.; Hamilton, J.H.; Ramayya, A.V.; Nettles, W.G.; Kawakami, H.; Spejewski, E.H.; Ijaz, M.A.; Toth, K.S.; Robinson, E.L.; Sastry, K.S.R.; Lin, J.; Avignone, F.T.; Brantley, W.H.; Rao, P.V.G.

    1976-01-01

    The new isotope 184 Tl has been identified with T 1 / 2 =11 +- 1 sec and the levels in 184 Hg investigated from its decay. The 0 + band head of a deformed band was found to drop to 375 keV in agreement with theoretical predictions. The mean life of the 375-keV 0 + level was measured to be 0.9 +- 0.3 nsec which is a factor of 10 faster than theoretically predicted for a shape-isomeric E2 transition

  7. Total flavonoid concentrations of bryophytes from Tianmu Mountain, Zhejiang Province (China: Phylogeny and ecological factors.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available The flavonoids in bryophytes may have great significance in phylogeny and metabolism research. However, to date there has been little research on bryophyte metabolites, especially flavonoids. To redress this somewhat, we determined flavonoid concentrations of bryophytes from Tianmu Mountain through a colorimetric assay and considered the factors influencing the results. This is the first time that the flavonoid contents of bryophytes have been examined in detail. The results revealed a range of total flavonoid concentrations in 90 samples collected from Tianmu Mountain from 1.8 to 22.3 mg/g (w/w. The total flavonoid contents of liverworts were generally higher than those of mosses; acrocarpous mosses had generally higher values than that of pleurocarpous mosses. The total flavonoid contents of bryophytes growing at lower light levels were general higher than those growing in full-sun. The total flavonoid contents of epiphytic bryophytes were highest, while those of aquatic bryophytes were the lowest. Total flavonoid contents of species growing at low-latitudes were much higher than those at high-latitude individuals. In conclusion, total flavonoid contents of bryophytes have some connection with plant phylogeny; more flavonoids might be contained in relatively primitive bryophytes. Meanwhile, the effects of ecological factors on total flavonoid contents of bryophytes exist; light and habitat (especially tree habitat and river habitat might be representative factor.

  8. An infrared study of the nitro—nitrito linkage isomerization in solid nitro- and nitritopentamminecobalt(III) chloride

    Science.gov (United States)

    Heyns, A. M.; de Waal, D.

    1989-01-01

    The photochemical isomerization reaction of [Co(NH 3) 5NO 2]Cl 2 to [Co(NH 3) 5ONO]Cl 2 has been studied in the solid state by means of i.r. spectroscopy. The reaction is first order with k = 2.53±0.05 × 10 -4s -1 and is much faster ( t1/2=49min) than the well-known spontaneous nitrito → nitro isomerization ( t1/2 = 6 days). The i.r. bands of both the NH 3 and ONO - -groups in the range 4000-50 cm -1 indicate minor differences between the structures of freshly and photochemically prepared [Co(NH 3) 5ONO]Cl 2. The far i.r. spectra indicate the disorder existing in the intermediate products during the isomerization processes.

  9. Determination of the isomeric fraction in a postaccelerated radioactive ion beam using the coupled decay-chain equations

    CERN Document Server

    Ekstrom, A; Dijulio, D D; Cederkall, J; Van de Walle, J

    2010-01-01

    A method based on the coupled decay-chain equations for extracting the isotopic and the isomeric composition of a postaccelerated radioactive ion beam is presented and demonstrated on a data set from a Coulomb excitation experiment. This is the first attempt of analyzing the content of a postaccelerated radioactive ion beam using this technique. The beam composition is required for an absolute normalization of the measurement. The strength of the method, as compared to present online-based methods, lies in the determination of the isomeric fraction of a partially isomeric beam using all data accumulated during the experiment. We discuss the limitations and sensitivity of the method with respect to the gamma-ray detection efficiency and the accumulated flux. (C) 2010 Elsevier B.V. All rights reserved.

  10. Antiherpetic activity of a flavonoid fraction from Ocotea notata leaves

    Directory of Open Access Journals (Sweden)

    Rafael Garrett

    2012-01-01

    Full Text Available This study describes the isolation of a flavonoid fraction from leaves of Ocotea notata (Nees & Mart. Mez, Lauraceae, the identification of six major compounds (an A-type proanthocyanidin trimer [3], isoquercitrin [4], reynoutrin [5], miquelianin [6], quercitrin [7], afzelin [8] and four minor compounds (catechin [1], epicatechin [2], quercetin [9], kaempferol [10] present in the fraction and its activity against the Herpes simplex virus type 1 (HSV-1 and type 2 (HSV-2. The 50% effective concentrations values (EC50 calculated from the dose-response curve and the selectivity indices (SI against the virus were: EC50 35.8 µg/mL and SI 5.5 to HSV-1 and EC50 23.5 µg/mL and SI 8.5 to HSV-2. The flavonoid fraction was more active against HSV-2 than HSV-1. The mechanisms of antiviral action of the flavonoid fraction against the virus were also evaluated. The percentage inhibition (PI obtained for HSV-2 was higher than 90% in the following assays: virucidal, pre-treatment of cells, treatment of cells after viral adsorption and treatment of cells after viral penetration. For HSV-1, the flavonoid fraction had no effect in pre-treatment of cells and showed 60% of inhibition in virucidal assay.

  11. Antiherpetic activity of a flavonoid fraction from Ocotea notata leaves

    Directory of Open Access Journals (Sweden)

    Rafael Garrett

    2012-04-01

    Full Text Available This study describes the isolation of a flavonoid fraction from leaves of Ocotea notata (Nees & Mart. Mez, Lauraceae, the identification of six major compounds (an A-type proanthocyanidin trimer [3], isoquercitrin [4], reynoutrin [5], miquelianin [6], quercitrin [7], afzelin [8] and four minor compounds (catechin [1], epicatechin [2], quercetin [9], kaempferol [10] present in the fraction and its activity against the Herpes simplex virus type 1 (HSV-1 and type 2 (HSV-2. The 50% effective concentrations values (EC50 calculated from the dose-response curve and the selectivity indices (SI against the virus were: EC50 35.8 µg/mL and SI 5.5 to HSV-1 and EC50 23.5 µg/mL and SI 8.5 to HSV-2. The flavonoid fraction was more active against HSV-2 than HSV-1. The mechanisms of antiviral action of the flavonoid fraction against the virus were also evaluated. The percentage inhibition (PI obtained for HSV-2 was higher than 90% in the following assays: virucidal, pre-treatment of cells, treatment of cells after viral adsorption and treatment of cells after viral penetration. For HSV-1, the flavonoid fraction had no effect in pre-treatment of cells and showed 60% of inhibition in virucidal assay.

  12. Cocoa and chocolate flavonoids: implications for cardiovascular health.

    Science.gov (United States)

    Steinberg, Francene M; Bearden, Monica M; Keen, Carl L

    2003-02-01

    This paper offers a review of current scientific research regarding the potential cardiovascular health benefits of flavonoids found in cocoa and chocolate. Recent reports indicate that the main flavonoids found in cocoa, flavan-3-ols and their oligomeric derivatives, procyanidins, have a variety of beneficial actions, including antioxidant protection and modulation of vascular homeostasis. These findings are supported by similar research on other flavonoid-rich foods. Other constituents in cocoa and chocolate that may also influence cardiovascular health are briefly reviewed. The lipid content of chocolate is relatively high; however, one third of the lipid in cocoa butter is composed of the fat stearic acid, which exerts a neutral cholesterolemic response in humans. Cocoa and chocolate contribute to trace mineral intake, which is necessary for optimum functioning of all biologic systems and for vascular tone. Thus, multiple components in chocolate, particularly flavonoids, can contribute to the complex interplay of nutrition and health. Applications of this knowledge include recommendations by health professionals to encourage individuals to consume a wide range of phytochemical-rich foods, which can include dark chocolate in moderate amounts.

  13. Ultrasonic extraction of flavonoids and phenolics from loquat ...

    African Journals Online (AJOL)

    Ethanol was used to extract flavonoids and phenolics from loquat (Eriobotrya japonica Lindl. cv. Ruantiaobaisha) flowers with ultrasonic pharmaceutical managing machine. Single-factor and orthogonal experiment were used to investigate the optimum extraction condition. The results showed that, the combination of 30°C, ...

  14. Flavonoids inhibit the respiratory burst of neutrophils in mammals

    Czech Academy of Sciences Publication Activity Database

    Číž, Milan; Denev, P.; Kratchanova, M.; Vašíček, Ondřej; Ambrožová, Gabriela; Lojek, Antonín

    2012-01-01

    Roč. 2012, č. 2012 (2012), ID 181295 ISSN 1942-0900 R&D Projects: GA ČR(CZ) GA524/08/1753 Institutional research plan: CEZ:AV0Z50040702 Keywords : flavonoids * neutrophils * respiratory burst Subject RIV: BO - Biophysics Impact factor: 3.393, year: 2012

  15. Health benefits of orange juice and citrus flavonoids

    Science.gov (United States)

    The main flavonoids found in orange juice are hesperidin and naringenin, which can affect several metabolic routes that improve blood serum antioxidant capacity and anti-inflammatory performance, while decreasing insulin resistance protecting against diabetes and metabolic syndrome. In addition, or...

  16. Extraction and Purification of Flavonoids from Radix Puerariae | Li ...

    African Journals Online (AJOL)

    Purpose: To develop an efficient method for the purification of flavonoids from Radix puerariae. Methods: Optimal extraction technology was obtained using orthogonal test. Through adsorption and desorption tests, 8 resins with different polarity, diameter, and surface area were studied. Finally, a novel macroporous resin, ...

  17. Antioxidant and Anti-Fatigue Activities of Flavonoids from Puerariae ...

    African Journals Online (AJOL)

    This study evaluated the antioxidant and anti-fatigue activities of flavonoids from Puerariae radix (FPR). In vitro antioxidant activities of FPR were investigated through hydroxyl and superoxide radical scavenging activities. In vivo anti-fatigue activity of FPR was investigated through loaded swimming exercise of mice. Results ...

  18. Singlet oxygen reactions with flavonoids. A theoretical-experimental study.

    Science.gov (United States)

    Morales, Javier; Günther, Germán; Zanocco, Antonio L; Lemp, Else

    2012-01-01

    Detection of singlet oxygen emission, λ(max) = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, k(T), and the reactive reaction rate constant, k(r), for the reaction between singlet oxygen and several flavonoids. Values of k(T) determined in deuterated water, ranging from 2.4×10(7) M(-1) s(-1) to 13.4×10(7) M(-1) s(-1), for rutin and morin, respectively, and the values measured for k(r), ranging from 2.8×10(5) M(-1) s(-1) to 65.7×10(5) M(-1) s(-1) for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid.

  19. Flavonoids as Nutraceuticals: A Review | Tapas | Tropical Journal of ...

    African Journals Online (AJOL)

    Due to the variety of pharmacological activities in the mammalian body, flavonoids are more correctly referred as “nutraceuticals”. Keywords: Bioflavonoids, Structure-Classification, Nutraceuticals, Antimicrobial activities, Anti-oxidant activity, Metabolic effects. Tropical Journal of Pharmaceutical Research Vol. 7 (3) 2008: pp.

  20. Flavonoids as Chemopreventive and Therapeutic Agents Against Lung Cancer

    Directory of Open Access Journals (Sweden)

    Albert Cabrera

    2014-05-01

    Full Text Available The objective of the present review is to study the relationship between flavonoids and lung cancer, proposing that their regular consumption in Western diets could be beneficial for protecting patients against lung cancer. An extensive search of the scientific literature was performed in the following electronic specialized databases (PubMed central (PMC-NBCI, Elsevier Journal, SciELO Spain, Scirus, Science Direct, including studies in animals, cells, and humans, in order to establish the effect of flavonoids in the prevention and development of lung cancer. Although in vitro and animal studies show the potential ability of flavonoids to act against different types of cancers, especially against lung cancers, the diverse results reported within epidemiological studies, together with the lack of experiments in humans, are the major factors in limiting making dietary recommendations based on scientific evidence for the management of patients with lung cancer. Therefore, the authors of the present study recommend following the dietary health practice guidelines which promotes the consumption of food enriched in flavonoids and reflects the current state of knowledge of an effective and appropriate diet in lung cancer patients.Erratum in: Rev Esp Nutr Hum Diet. 2013;17(2:91-92Link: http://www.renhyd.org/index.php/renhyd/article/view/6/17

  1. Microbial production of the flavonoids garbanzol, resokaempferol and fisetin

    DEFF Research Database (Denmark)

    2016-01-01

    The invention provides a genetically modified micro-organism comprising one or more transgene for the production of one or more of the flavonoids garbanzol, resokaempferol and fisetin. The micro-organism may be a bacterial or yeast cell engineered to express a metabolic pathway for garbanzol...

  2. Antioxidant and Anti-proliferative Activities of Flavonoids from ...

    African Journals Online (AJOL)

    significant growth inhibitory effect on RKO cells with IC50 of 39.08 μmol/L and 17.68 μmol/L, respectively ..... YJ.. Essential oil from rhizomes of Ligusticum chuanxiong induces apoptosis in hypertrophic scar ... Liu H, Mou Y, Zhao J, Wang J, Zhou L, Wang M, Wang. D, Han J, Yu Z, Yang F. Flavonoids from Halostachys.

  3. Flavonoid biosynthesis controls fiber color in naturally colored cotton

    Directory of Open Access Journals (Sweden)

    Hai-Feng Liu

    2018-04-01

    Full Text Available The existence of only natural brown and green cotton fibers (BCF and GCF, respectively, as well as poor fiber quality, limits the use of naturally colored cotton (Gossypium hirsutum L.. A better understanding of fiber pigment regulation is needed to surmount these obstacles. In this work, transcriptome analysis and quantitative reverse transcription PCR revealed that 13 and 9 phenylpropanoid (metabolic pathway genes were enriched during pigment synthesis, while the differential expression of phenylpropanoid (metabolic and flavonoid metabolic pathway genes occurred among BCF, GCF, and white cotton fibers (WCF. Silencing the chalcone flavanone isomerase gene in a BCF line resulted in three fiber phenotypes among offspring of the RNAi lines: BCF, almost WCF, and GCF. The lines with almost WCF suppressed chalcone flavanone isomerase, while the lines with GCF highly expressed the glucosyl transferase (3GT gene. Overexpression of the Gh3GT or Arabidopsis thaliana 3GT gene in BCF lines resulted in GCF. Additionally, the phenylpropanoid and flavonoid metabolites of BCF and GCF were significantly higher than those of WCF as assessed by a metabolomics analysis. Thus, the flavonoid biosynthetic pathway controls both brown and green pigmentation processes. Like natural colored fibers, the transgenic colored fibers were weaker and shorter than WCF. This study shows the potential of flavonoid pathway modifications to alter cotton fibers’ color and quality.

  4. A quantum chemical explanation of the antioxidant activity af flavonoids.

    NARCIS (Netherlands)

    van Acker, S.A.B.E.; de Groot, M.J.; van den Berg, D.J.; Tromp, M.N.J.L.; Donné-Op den Kelder, G.M.; van der Vijgh, W.J.F.; Bast, A.

    1996-01-01

    Flavonoids are a group of naturally occurring antioxidants, which over the past years have gained tremendous interest because of their possible therapeutic applicability. The mechanism of their antioxidant activity has been extensively studied over several decades. However, there is still much

  5. Quantification of alkaloids, phenols and flavonoids in sunflower ...

    African Journals Online (AJOL)

    Allelochemicals in leaves, stems and roots of sunflower (cv Hysun 38) were determined using thin layer chromatography (TLC) for alkaloids and spectrophotometry for phenols and flavonoids. In the TLC, the highest Rf value was recorded in leaves, followed by roots and stems, a sequence that held true also for the quantity ...

  6. Dietary Antioxidant and Flavonoid Intakes Are Reduced in the Elderly

    Directory of Open Access Journals (Sweden)

    Małgorzata Elżbieta Zujko

    2015-01-01

    Full Text Available The objective of this study was to determine sources and patterns of antioxidant and flavonoid intakes in the elderly (61–74 yrs in comparison with young (20–40 yrs and middle age (41–60 yrs groups in a cross-sectional study. More than 6000 subjects of both genders, aged 20–74 years, participants of the National Multicenter Health Survey (WOBASZ took part in this study. Daily food consumption was estimated by the single 24-hour dietary recall. Dietary total antioxidant capacity (TAC and flavonoid content (FC were calculated according to the amount of food consumed by the participants combined with antioxidant capacity and flavonoid contents in foods. Food consumption, dietary TAC, and FC were significantly lower in the elderly, especially elderly women in comparison to the young and middle age groups. The consumption of tea, coffee, and apples was associated with the largest contribution to dietary TAC and FC in all participants. Despite high nutrient density of the energy-adjusted diet of ageing people, the elderly consumed the lowest amounts of antioxidants and flavonoids due to the lowest food intake.

  7. Effect of citrus flavonoids on HL-60 cell differentiation.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

    1999-01-01

    Twenty-seven Citrus flavonoids were examined for their activity of induction of terminal differentiation of human promyelocytic leukemia cells (HL-60) by nitro blue tetrazolium (NBT) reducing, nonspecific esterase, specific esterase, and phagocytic activities. 10 flavonoids were judged to be active (percentage of NBT reducing cells was more than 40% at a concentration of 40 microM), and the rank order of potency was natsudaidain, luteolin, tangeretin, quercetin, apigenin, 3, 3, '4, '5, 6, 7, 8-heptamethoxyflavone, nobiletin, acacetin, eriodictyol, and taxifolin. These flavonoids exerted their activity in a dose-dependent manner. HL-60 cells treated with these flavonoids differentiated into mature monocyte/macrophage. The structure-activity relationship established from comparison between flavones and flavanones revealed that ortho-catechol moiety in ring B and C2-C3 double bond had an important role for induction of differentiation of HL-60. In polymethoxylated flavones, hydroxyl group at C3 and methoxyl group at C8 enhanced the differentiation-inducing activity.

  8. Main flavonoids in needles of Larix decidu A

    NARCIS (Netherlands)

    Niemann, Gerard J.

    Present work. Freeze-dried needles were extracted with acetone-water. Ether and butanol fractions were separated by repeated banding on paper. Nine major flavonoids were isolated (in solution) and identified by chromatographic and UV spectral data of both the original and alkaline and/or acid

  9. Kaempferol, a flavonoid compound from Gynura medica induced ...

    African Journals Online (AJOL)

    Background: Kaempferol, a natural flavonoid, has been shown to induce cancer cell apoptosis and cell growth inhibition in several tumors. Previously we have conducted a full investigation on the chemical constituents of Gynura medica, kaempferol and its glycosides are the major constituents of G. medica. Here we ...

  10. Antioxidant activity and total phenolic and flavonoid content of ...

    African Journals Online (AJOL)

    The antioxidant capacity of the flowering aerial parts of Astragalus squarrosus was determined by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric thiocyanate methods. The phenolic and flavonoid content was also measured. A. squarrosus showed weak free radical scavenging activity with the DPPH ...

  11. Singlet Oxygen Reactions with Flavonoids. A Theoretical – Experimental Study

    Science.gov (United States)

    Morales, Javier; Günther, Germán; Zanocco, Antonio L.; Lemp, Else

    2012-01-01

    Detection of singlet oxygen emission, λmax = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, kT, and the reactive reaction rate constant, kr, for the reaction between singlet oxygen and several flavonoids. Values of kT determined in deuterated water, ranging from 2.4×107 M−1s−1 to 13.4×107 M−1s−1, for rutin and morin, respectively, and the values measured for kr, ranging from 2.8×105 M−1s−1 to 65.7×105 M−1s−1 for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid. PMID:22802966

  12. Singlet oxygen reactions with flavonoids. A theoretical-experimental study.

    Directory of Open Access Journals (Sweden)

    Javier Morales

    Full Text Available Detection of singlet oxygen emission, λ(max = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, k(T, and the reactive reaction rate constant, k(r, for the reaction between singlet oxygen and several flavonoids. Values of k(T determined in deuterated water, ranging from 2.4×10(7 M(-1 s(-1 to 13.4×10(7 M(-1 s(-1, for rutin and morin, respectively, and the values measured for k(r, ranging from 2.8×10(5 M(-1 s(-1 to 65.7×10(5 M(-1 s(-1 for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid.

  13. FLAVONOIDS IN THE GRASS OF TRIBULUS TERRESTRIS L.

    Directory of Open Access Journals (Sweden)

    P. E. Khudenko

    2015-01-01

    Full Text Available The article presents active parts of Tribulus terrestris L. as a perspective sample for study. We have provided an example of flavo-noids determination with high-performance liquid chromatography / MS at the Waters Acquility chromatographer with tandem quad-rupolar MS-detector TQD (Waters.

  14. Quercitrin: an antileishmanial flavonoid glycoside from Kalanchoe pinnata.

    Science.gov (United States)

    Muzitano, Michelle F; Cruz, Elaine A; de Almeida, Ana Paula; Da Silva, Silvia A G; Kaiser, Carlos R; Guette, Catherine; Rossi-Bergmann, Bartira; Costa, Sônia S

    2006-01-01

    Quercitrin (quercetin 3- O-alpha- L-rhamnopyranoside), one of the constituents of the biologically active aqueous extract obtained from Kalanchoe pinnata, is demonstrated to be a potent antileishmanial compound (IC50 approximately 1 microg/mL) with a low toxicity profile. This is the first time that antileishmanial activity is demonstrated for a flavonoid glycoside.

  15. The antileishmanial activity assessment of unusual flavonoids from Kalanchoe pinnata.

    Science.gov (United States)

    Muzitano, Michelle F; Tinoco, Luzineide W; Guette, Catherine; Kaiser, Carlos R; Rossi-Bergmann, Bartira; Costa, Sônia S

    2006-09-01

    The importance of flavonoids for the antileishmanial activity of Kalanchoe pinnata was previously demonstrated by the isolation of quercitrin, a potent antileishmanial flavonoid. In the present study, the aqueous leaf extract from the medicinal plant K. pinnata (Crassulaceae) afforded a kaempferol di-glycoside, named kapinnatoside, identified as kaempferol 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (1). In addition, two unusual flavonol and flavone glycosides already reported, quercetin 3-O-alpha-L-arabinopyranosyl (1-->2) alpha-L-rhamnopyranoside (2) and 4',5-dihydroxy-3',8-dimethoxyflavone 7-O-beta-D-glucopyranoside (3), have been isolated. Their structures were determined via analyses of mono and bi-dimensional (1)H and (13)C NMR spectroscopic experiments and HR-MALDI mass spectra. Because of its restricted occurrence and its abundance in K. pinnata, flavonoid (2) may be a chemical marker for this plant species of high therapeutic potential. The three flavonoids were tested separately against Leishmania amazonenis amastigotes in comparison with quercitrin, quercetin and afzelin. The quercetin aglycone - type structure, as well as a rhamnosyl unit linked at C-3, seem to be important for antileishmanial activity.

  16. Ultrasonic-Assisted Extraction and Antioxidant Activity of Flavonoids ...

    African Journals Online (AJOL)

    Lee WC, Yusof Y, Hamid NSA, Baharin BS. Optimizing conditions for hot water extraction of banana juice using response surface methodology (RSM). J Food. Eng 2006; 75: 473-479. 11. Proestos C, Sereli D, Komaitis M. Analysis of flavonoids and phenolic acids in Greek aromatic plants: Investigation of their antioxidant ...

  17. Total Phenol amd Flavonoid contents of Crude Extract and Fractions ...

    African Journals Online (AJOL)

    Phenolic compounds are numerous in plants and are essential part of human diet. Picralima nitida has been extensively used in African folk medicine especially in West Africa. The present study evaluated the total phenolic and flavonoid contents of the extract and fractions of Picralima nitida. The methanol extracts of P.

  18. Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion.

    Science.gov (United States)

    Soares, Juliana Mikaelly Dias; Pereira Leal, Ana Ediléia Barbosa; Silva, Juliane Cabral; Almeida, Jackson R G S; de Oliveira, Helinando Pequeno

    2017-01-01

    The development of alternatives for insulin secretion control in vivo or in vitro represents an important aspect to be investigated. In this direction, natural products have been progressively explored with this aim. In particular, flavonoids are potential candidates to act as insulin secretagogue. To study the influence of flavonoid on overall modulation mechanisms of insulin secretion. The research was conducted in the following databases and platforms: PubMed, Scopus, ISI Web of Knowledge, SciELO, LILACS, and ScienceDirect, and the MeSH terms used for the search were flavonoids, flavones, islets of Langerhans, and insulin-secreting cells. Twelve articles were included and represent the basis of discussion on mechanisms of insulin secretion of flavonoids. Papers in ISI Web of Knowledge were in number of 1, Scopus 44, PubMed 264, ScienceDirect 511, and no papers from LILACS and SciELO databases. According to the literature, the majority of flavonoid subclasses can modulate insulin secretion through several pathways, in an indication that corresponding molecule is a potential candidate for active materials to be applied in the treatment of diabetes. The action of natural products on insulin secretion represents an important investigation topic due to their importance in the diabetes controlIn addition to their typical antioxidant properties, flavonoids contribute to the insulin secretionThe modulation of insulin secretion is induced by flavonoids according to different mechanisms. Abbreviations used: K ATP channels: ATP-sensitive K + channels, GLUT4: Glucose transporter 4, ERK1/2: Extracellular signal-regulated protein kinases 1 and 2, L-VDCCs: L-type voltage-dependent Ca +2 channels, GLUT1: Glucose transporter 1, AMPK: Adenosine monophosphate-activated protein kinase, PTP1B: Protein tyrosine phosphatase 1B, GLUT2: Glucose transporter 2, cAMP: Cyclic adenosine monophosphate, PKA: Protein kinase A, PTK: Protein tyrosine kinase, CaMK II: Ca 2+ /calmodulin

  19. Photo-isomerization induced rapid photo-degradation of optical nonlinearity in cyano substituted stilbene derivative doped poled polymer

    International Nuclear Information System (INIS)

    Yan Jieyun; Liu Liying; Ji Liyong; Ye Mingxin; Xu Lei; Wang Wencheng

    2004-01-01

    We found that, although alpha'-cyano-4'-nitro-4-N, N-dimethylaminostilbene has larger hyperpolarizability than that of conventional 4'-N, N-dimethylamino-nitrostilbene, the addition of the cyano group makes it much more easy to photo-isomerize, thus destroying the molecular ordering in poled chromophore doped polymers. Experimental evidence was obtained by monitoring the second-harmonic generation intensity, UV-Vis absorption spectrum, and FTIR spectrum. The photo-isomerization reaction process was monitored by optical pump induced absorption anisotropy measurement. Comparisons with the behaviour of a azobenzene dye are also made

  20. Modulating the Physical and Electronic Properties over Positional Isomerism: The Dispirofluorene-Dihydroindacenodithiophene (DSF-IDT) Family.

    Science.gov (United States)

    Peltier, Jean-David; Heinrich, Benoît; Donnio, Bertrand; Jeannin, Olivier; Rault-Berthelot, Joëlle; Poriel, Cyril

    2017-12-06

    We report the first studies on the intrinsic properties of a meta-substituted dihydroindacenodithienyl fragment and more generally the strong impact of positional isomerism on dihydroindacenodithiophene derivatives. The influence of the para and meta linkages has notably been highlighted not only for the electronic properties in solution (electrochemical properties, anodic polymerization, HOMO/LUMO energy levels, optical transitions, fluorescence spectra) but also on the physical properties in the solid state (molecular organization, crystallinity, and phase transitions). The positional isomerism hence appears to be a very efficient tool to drastically tune the properties of dihydroindacenodithiophene derivatives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Isomeric cross-section ratios of some (n,2n) reactions at 14. 7 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Garg, K C; Khurana, C S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1979-08-01

    Isomeric cross-section ratios of (n,2n) reactions at 14.7 MeV leading to the millisecond isomeric levels have been calculated theoretically using the statistical theory of nuclear reactions and the spin distribution form due to Bethe and Bloch. The theoretical ratios have been compared with the experimentally measured values in order to evaluate the spin cut-off parameter sigma. This parameter has been used to calculate the effective moment of inertia of the nucleus to draw useful conclusions from the results of present calculations.

  2. First observation of high spin states and isomeric decay in 210Fr

    International Nuclear Information System (INIS)

    Kanjilal, D.; Saha, S.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R.; Muralithar, S.; Singh, R. P.; Mukherjee, G.; Mukherjee, B.

    2011-01-01

    The first observation of the prompt and the delayed γ transitions involving the high spin states in 210 Fr is reported. The decay of the high spin states and the isomeric levels of 210 Fr, identified for the first time from the known sequence of low-lying transitions found earlier in the α decay of 214 Ac, were studied. High spin states of the doubly-odd 210 Fr, which were produced by the fusion evaporation reaction 197 Au ( 16 O, xn) 213-x Fr, were populated and the subsequent emitted γ rays were detected through the high-sensitivity germanium clover detector array INGA. The level scheme up to yrast levels of 5.3 MeV excitation energy and ∼20(ℎ/2π) angular momentum could be established for the first time through γγ, γγΔT coincidence, and DCO ratio measurements. A new low-lying isomeric transition at E γ = 203(2) keV was observed. The half-life was measured to be T 1/2 = 41(2) ns. The measured half-life was compared with the corresponding single-particle estimate, based on the level scheme obtained from the experiment.

  3. 1,2-Fluorine Radical Rearrangements: Isomerization Events in Perfluorinated Radicals.

    Science.gov (United States)

    Van Hoomissen, Daniel J; Vyas, Shubham

    2017-11-16

    Devising effective degradation technologies for perfluoroalkyl substances (PFASs) is an active area of research, where the molecular mechanisms involving both oxidative and reductive pathways are still elusive. One commonly neglected pathway in PFAS degradation is fluorine atom migration in perfluoroalkyl radicals, which was largely assumed to be implausible because of the high C-F bond strength. Using density functional theory calculations, it was demonstrated that 1,2-F atom migrations are thermodynamically favored when the fluorine atom migrated from a less branched carbon center to a more branched carbon center. Activation barriers for these rearrangements were within 19-29 kcal/mol, which are possible to easily overcome at elevated temperatures or in photochemically activated species in the gas or aqueous phase. It was also found that the activation barriers for the 1,2-F atom migration are lowered as much as by 10 kcal/mol when common oxidative degradation products such as HF assisted the rearrangements or if the resulting radical center was stabilized by vicinal π-bonds. Natural bond orbital analyses showed that fluorine moves as a radical in a noncharge-separated state. These findings add an important reaction to the existing knowledge of mechanisms for PFAS degradation and highlights the fact that 1,2-F atom shifts may be a small channel for isomerization of these compounds, but upon availability of mineralization products, this isomerization process could become more prominent.

  4. An Insight into Flotation Chemistry of Pyrite with Isomeric Xanthates: A Combined Experimental and Computational Study

    Directory of Open Access Journals (Sweden)

    Guihong Han

    2018-04-01

    Full Text Available The flotation chemistry between pyrite and isomeric xanthates (butyl xanthate and isobutyl xanthate was investigated by means of adsorption experiments, surface tension tests, and molecular dynamic simulations in this work. The flotation chemical results were confirmed and further interpreted by quantum chemical calculations. The experiment results demonstrated that the isobutyl xanthate exhibited superior adsorption capacity and surface activity than those of butyl xanthate in flotation chemistry. In addition, molecular dynamic simulations were simultaneously performed in constant number, constant volume and temperature (NVT, and constant number, constant volume, and pressure (NPT ensemble, indicating that the NPT ensemble was more suitable to the flotation system and the isobutyl xanthate was easier to be adsorbed on pyrite surface compared with butyl xanthate during an appropriate range of concentrations. Furthermore, the quantum chemical calculations elucidated that the isobutyl xanthate presented higher reactivity than that of the corresponding butyl xanthate based on the frontier molecular orbital theory of chemical reactivity, which was consistent with experimental and simulation results obtained. This work can provide theoretical guidance for an in-depth study of the flotation chemistry of pyrite with isomeric xanthates.

  5. In vitro metabolism of nitric oxide-donating aspirin: the effect of positional isomerism.

    Science.gov (United States)

    Gao, Jianjun; Kashfi, Khosrow; Rigas, Basil

    2005-03-01

    NO-donating aspirin (NO-ASA) is a potentially important chemopreventive agent against cancer. Since positional isomerism affects strongly its potency in inhibiting colon cancer cell growth, we studied the metabolic transformations of its ortho-, meta-, and para-isomers in rat liver and colon cytosolic, microsomal, and mitochondrial fractions as well as in intact HT-29 human colon cancer cells. NO-ASA and metabolites were determined by high-performance liquid chromatography and products identified by mass spectroscopy, as required. For all three isomers, the acetyl group on the ASA moiety was hydrolyzed rapidly. This was followed by hydrolysis of the ester bond linking the salicylate anion to the spacer. The ortho- and para-isomers produced salicylic acid and a putative intermediate consisting of the remainder of the molecule, which via a rapid step generated nitrate, (hydroxymethyl)phenol, and a conjugate of spacer with glutathione. The meta-isomer, in contrast, generated salicylic acid and (nitroxymethyl)phenol, the latter leading to (hydroxymethyl)phenol and the glutathione-spacer conjugate. This metabolic pathway takes place in its entirety only in the cytosolic fraction of the tissues tested and in intact human colon cancer cells, perhaps reflecting exposure to the cytosolic glutathione S-transferase, which catalyzes the formation of the spacer-glutathione conjugate. Thus, the three positional isomers of NO-ASA differ in their metabolism and these differences correlate with their differential effects on cancer cell growth, underscoring the importance of positional isomerism in modulating drug effects.

  6. Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

    Science.gov (United States)

    Han, Huixian; Li, Anyang; Guo, Hua

    2014-12-01

    A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S0) electronic state has been constructed by fitting ˜37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm-1. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm-1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

  7. Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

    International Nuclear Information System (INIS)

    Han, Huixian; Li, Anyang; Guo, Hua

    2014-01-01

    A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S 0 ) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm −1 . The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm −1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction

  8. Schiff base switch II precedes the retinal thermal isomerization in the photocycle of bacteriorhodopsin.

    Directory of Open Access Journals (Sweden)

    Ting Wang

    Full Text Available In bacteriorhodopsin, the order of molecular events that control the cytoplasmic or extracellular accessibility of the Schiff bases (SB are not well understood. We use molecular dynamics simulations to study a process involved in the second accessibility switch of SB that occurs after its reprotonation in the N intermediate of the photocycle. We find that once protonated, the SB C15 = NZ bond switches from a cytoplasmic facing (13-cis, 15-anti configuration to an extracellular facing (13-cis, 15-syn configuration on the pico to nanosecond timescale. Significantly, rotation about the retinal's C13 = C14 double bond is not observed. The dynamics of the isomeric state transitions of the protonated SB are strongly influenced by the surrounding charges and dielectric effects of other buried ions, particularly D96 and D212. Our simulations indicate that the thermal isomerization of retinal from 13-cis back to all-trans likely occurs independently from and after the SB C15 = NZ rotation in the N-to-O transition.

  9. Material Balance And Reaction Kinetics Modeling For Penex Isomerization Process In Daura Refinery

    Directory of Open Access Journals (Sweden)

    Hamadi Adel Sharif

    2017-01-01

    Full Text Available Penex Deisohexanizer isomerization of light straight run naphtha is a significant process for petroleum refining and proved to be effective technology to produce gasoline components with a high octane number. Modeling of the chemical kinetic reactions is an important tool because it is a better tool for optimization of the experimental data into parameters used for industrial reactors. The present study deals on the isomerization process in Daura refinery. Material balance calculations were done mathematically on the unit for the kinetics prediction purpose. A kinetic mathematical model was derived for the prediction rate constants K1 and K2 and activation energy Ea at operating temperatures range 120-180°C. According to the model, the results show that with increasing of temperature leads to increased K1 directly, where the K2 values proportional inversely. The activation energy results show that Ea1(nC6

  10. Isotopic study on mechanism for skeletal isomerization of n-butane over solid acids

    International Nuclear Information System (INIS)

    Suzuki, Tetsuo; Okuhara, Toshio

    2000-01-01

    Reaction mechanism for skeletal isomerization of n-butane over typical strong solid acids were investigated by using 1,4- 13 C 2 -n-butane. We used FI MASS for the analysis of 13 C distribution to get the parent pattern. 13 C-distribution of isobutane formed at 423 K over SO 3 2- /ZrO 2 (SZ) and Cs 2.5 H 0.5 PW 12 O 40 (Cs2.5) were close to binomial distributions, indicating that the isomerization proceeded mainly via a bimolecular mechanism on these catalysts. On the other hand, at 523 K over Cs2.5, the isotopic distribution pattern in isobutane was quite different from the binomial one; the fraction of 13 C 2 -isobutane was much greater than the binomial distribution. This result demonstrates that an intramolecular (monomolecular) rearrangement became significant at 523 K over Cs2.5. The contribution of monomolecular pathway was higher on Cs2.5 than on SZ. We presumed that the contribution of mechanism is related to the acidic property and the dehydrogenation ability of the catalyst. (S.Y.)

  11. Isomeric signatures in the fragmentation of pyridazine and pyrimidine induced by fast ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ (Brazil)

    2015-07-28

    We present fast proton impact induced fragmentations of pyrimidine and pyridazine as an experimental resource to investigate isomeric signatures. Major isomeric imprints are identified for few fragment ions and differences of more than an order of magnitude for the cross sections of fragments of the same mass were measured. The observation of the molecular structure of these isomers gives no apparent indication for the reasons for such substantial differences. It is verified that the simple displacement of the position of one nitrogen atom strongly inhibits or favors the production of some ionic fragment species. The dependency of the fragmentation cross sections on the proton impact energy, investigated by means of time of flight mass spectroscopy and of a model calculation based in first order perturbation theory, allows us to disentangle the complex collision dynamics of the ionic fragments. The proton-induced fragmentation discriminates rather directly the association between a molecular orbital ionization and the fragment-ions creation and abundance, as well as how the redistribution of the energy imparted to the molecules takes place, triggering not only single but also double vacancy and leads to specific fragmentation pathways.

  12. Thermodynamic calculation of simultaneous reactions of n-butane isomerization and isobutane alkylation with ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Batyrshin, N.N.; Beresneva, L.D.; Sidorov, V.A.

    1981-08-01

    Industrial production of ethylene alkylate has gained further development in connection with worldwide ecological problems and the planned changeover of automobile transport to unleaded gasolines, but the scale of production is still substantially less than that of sulfuric acid or hydrogen fluoride alkylates. This is due both to the instability of market prices for ethylene and the shortage of isobutane - a raw material for these large-tonnage production processes and for the synthetic rubber industry. The latter difficulty can be overcome by combining processes of isomerization of n-butane and alkylation of the resultant isobutane with ethylene in a single reaction unit. The possibility of combining these reactions using AlCl/sub 3/-based catalysts has been pointed out previously but in the literature there are no theoretical developments of technology or thermodynamic substantiation of a combined process. We have made a thermodynamic calculation of the consecutive (series-parallel) reactions of isomerization and alkylation with the goal of determining suitable technological conditions for carrying them out simultaneously and establishing the expected equilibrium yields of target products and the compositions of the reaction mixture.

  13. Impact of Plant-Derived Flavonoids on Neurodegenerative Diseases.

    Science.gov (United States)

    Costa, Silvia Lima; Silva, Victor Diogenes Amaral; Dos Santos Souza, Cleide; Santos, Cleonice Creusa; Paris, Irmgard; Muñoz, Patricia; Segura-Aguilar, Juan

    2016-07-01

    Neurodegenerative disorders have a common characteristic that is the involvement of different cell types, typically the reactivity of astrocytes and microglia, characterizing gliosis, which in turn contributes to the neuronal dysfunction and or death. Flavonoids are secondary metabolites of plant origin widely investigated at present and represent one of the most important and diversified among natural products phenolic groups. Several biological activities are attributed to this class of polyphenols, such as antitumor activity, antioxidant, antiviral, and anti-inflammatory, among others, which give significant pharmacological importance. Our group have observed that flavonoids derived from Brazilian plants Dimorphandra mollis Bent., Croton betulaster Müll. Arg., e Poincianella pyramidalis Tul., botanical synonymous Caesalpinia pyramidalis Tul. also elicit a broad spectrum of responses in astrocytes and neurons in culture as activation of astrocytes and microglia, astrocyte associated protection of neuronal progenitor cells, neuronal differentiation and neuritogenesis. It was observed the flavonoids also induced neuronal differentiation of mouse embryonic stem cells and human pluripotent stem cells. Moreover, with the objective of seeking preclinical pharmacological evidence of these molecules, in order to assess its future use in the treatment of neurodegenerative disorders, we have evaluated the effects of flavonoids in preclinical in vitro models of neuroinflammation associated with Parkinson's disease and glutamate toxicity associated with ischemia. In particular, our efforts have been directed to identify mechanisms involved in the changes in viability, morphology, and glial cell function induced by flavonoids in cultures of glial cells and neuronal cells alone or in interactions and clarify the relation with their neuroprotective and morphogetic effects.

  14. Habitual intake of dietary flavonoids and risk of Parkinson disease.

    Science.gov (United States)

    Gao, X; Cassidy, A; Schwarzschild, M A; Rimm, E B; Ascherio, A

    2012-04-10

    To prospectively examine whether higher intakes of total flavonoids and their subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones, and polymers) were associated with a lower risk of developing Parkinson disease (PD). In the current analysis, we included 49,281 men in the Health Professional Follow-up Study and 80,336 women from the Nurses' Health Study. Five major sources of flavonoid-rich foods (tea, berry fruits, apples, red wine, and orange/orange juice) were also examined. Flavonoid intake was assessed using an updated food composition database and a validated food frequency questionnaire. We identified 805 participants (438 men and 367 women) who developed PD during 20-22 years of follow-up. In men, after adjusting for multiple confounders, participants in the highest quintile of total flavonoids had a 40%lower PD risk than those in the lowest quintile (hazard ratio [HR] = 0.60; 95% confidence interval 0.43, 0.83; p trend = 0.001). No significant relationship was observed in women (p trend = 0.62) or in pooled analyses (p trend = 0.23). In the pooled analyses for the subclasses, intakes of anthocyanins and a rich dietary source, berries, were significantly associated with a lower PD risk (HR comparing 2 extreme intake quintiles were 0.76 for anthocyanins and 0.77 for berries, respectively; p trend < 0.02 for both). Our findings suggest that intake of some flavonoids may reduce PD risk, particularly in men, but a protective effect of other constituents of plant foods cannot be excluded.

  15. [Seasonal changes and response to stress of total flavonoids content of Farfugium japonicum].

    Science.gov (United States)

    Cui, Dalian; Ma, Yuxin

    2013-05-01

    To investigate the seasonal variation of total flavonoid content of Farfugium japonicum and its response to stress. The total flavonoids of Farfugium japonicum were determined by spectrophotometry in different seasons and under various stressful factors. The total flavonoid content in Farfugium japonicum leaves was the highest, followed by the petiole, and rhizomes (Pseasons (Pwater stress, the total flavonoid content in Farfugium japonicum leaves gradually increased, that in petiole first increased and then decreased,while that in rhizomes decreased (Pstress, the total flavonoid content in leaves, petioles and rhizomes of Farfugium japonicum showed a decreasing trend (Pseasons and that in different parts of the plant has different responses to ecological stressful factors.

  16. Interaction of flavonoids, the naturally occurring antioxidants with different media: A UV-visible spectroscopic study

    Science.gov (United States)

    Naseem, Bushra; Shah, S. W. H.; Hasan, Aurangzeb; Sakhawat Shah, S.

    2010-04-01

    Quantitative parameters for interaction of flavonoids—the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, Kc. Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities.

  17. Flavonoids at the pharma-nutrition interface: Is a therapeutic index in demand?

    Science.gov (United States)

    Peluso, Ilaria; Palmery, Maura

    2015-04-01

    The consumption of flavonoid-rich foods could have beneficial effects on health. However, different classes of flavonoids have different effect on disease risk and the relationship between flavonoid intake and risk of disease appeared to be non-linear. Furthermore, contrarily to vitamins, there are no symptoms of deficiency for flavonoids; therefore, our body treats them like other xenobiotics. Therefore, a therapeutic index should be determined. Despite flavonoids are at the pharma-nutrition interface, drugs and foods are subject to different regulatory frameworks and there is no recommended daily allowance (RDA) for flavonoids. Relatively little is known about the efficacy, safety and underlying mechanisms of these bioactive compounds, especially when taken in concert with drugs. Flavonoids could act both as drugs and pro-drugs with pharmacological and toxicological promiscuity. Due to the low bioavailability, the gastrointestinal tract could be the primary target of flavonoids and metabolites. Different effects have been observed after acute and chronic consumption and bioavailability and bioactivity have high inter-individual variability. Furthermore, the difficulties in the design and in the interpretation of human intervention studies make difficult the establishment of a therapeutic index for flavonoids. Probably the concept of 'personalized nutrition' previously proposed could be the better approach. However, despite more studies are needed in order to establish a therapeutic index for each flavonoid subclasses, at the moment RDA of total flavonoids could be between 250-400 mg/d, respecting the seasonality of food sources. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Metabolomics analysis reveals the metabolic and functional roles of flavonoids in light-sensitive tea leaves.

    Science.gov (United States)

    Zhang, Qunfeng; Liu, Meiya; Ruan, Jianyun

    2017-03-20

    As the predominant secondary metabolic pathway in tea plants, flavonoid biosynthesis increases with increasing temperature and illumination. However, the concentration of most flavonoids decreases greatly in light-sensitive tea leaves when they are exposed to light, which further improves tea quality. To reveal the metabolism and potential functions of flavonoids in tea leaves, a natural light-sensitive tea mutant (Huangjinya) cultivated under different light conditions was subjected to metabolomics analysis. The results showed that chlorotic tea leaves accumulated large amounts of flavonoids with ortho-dihydroxylated B-rings (e.g., catechin gallate, quercetin and its glycosides etc.), whereas total flavonoids (e.g., myricetrin glycoside, epigallocatechin gallate etc.) were considerably reduced, suggesting that the flavonoid components generated from different metabolic branches played different roles in tea leaves. Furthermore, the intracellular localization of flavonoids and the expression pattern of genes involved in secondary metabolic pathways indicate a potential photoprotective function of dihydroxylated flavonoids in light-sensitive tea leaves. Our results suggest that reactive oxygen species (ROS) scavenging and the antioxidation effects of flavonoids help chlorotic tea plants survive under high light stress, providing new evidence to clarify the functional roles of flavonoids, which accumulate to high levels in tea plants. Moreover, flavonoids with ortho-dihydroxylated B-rings played a greater role in photo-protection to improve the acclimatization of tea plants.

  19. Dietary flavonoids of Spanish youth: intakes, sources, and association with the Mediterranean diet

    Directory of Open Access Journals (Sweden)

    Rowaedh Ahmed Bawaked

    2017-05-01

    Full Text Available Background Plant-based diets have been linked to high diet quality and reduced risk of cardiovascular diseases. The health impact of plant-based diets might be partially explained by the concomitant intake of flavonoids. Estimation of flavonoids intake in adults has been important for the development of dietary recommendations and interventions for the prevention of weight gain and its consequences. However, estimation of flavonoids intake in children and adolescents is limited. Methods Average daily intake and sources of flavonoids were estimated for a representative national sample of 3,534 children and young people in Spain, aged 2–24 years. The data was collected between 1998 and 2000 by 24-h recalls. The Phenol-Explorer database and the USDA database on flavonoids content were used. Adherence to the Mediterranean diet was measured by the KIDMED index. Results The mean and median intakes of total flavonoids were 70.7 and 48.1 mg/day, respectively. The most abundant flavonoid class was flavan-3-ols (35.7%, with fruit being the top food source of flavonoids intake (42.8%. Total flavonoids intake was positively associated with the KIDMED index (p < 0.001. Conclusion The results of this study provide primary information about flavonoids intake and main food sources in Spanish children, adolescents and young adults. Participants with high daily mean intake of flavonoids have higher adherence to the Mediterranean diet.

  20. Flavonoid engineering of flax potentiate its biotechnological application

    Directory of Open Access Journals (Sweden)

    Prescha Anna

    2011-01-01

    Full Text Available Abstract Background Flavonoids are a group of secondary plant metabolites important for plant growth and development. They show also a protective effect against colon and breast cancer, diabetes, hypercholesterolemic atherosclerosis, lupus nephritis, and immune and inflammatory reactions. Thus, overproduction of these compounds in flax by genetic engineering method might potentiate biotechnological application of these plant products. Results Flax plants of third generation overexpressing key genes of flavonoid pathway cultivated in field were used as plant material throughout this study. The biochemical properties of seed, oil and seedcake extracts and fibre from natural and transgenic flax plants were compared. The data obtained suggests that the introduced genes were stably inherited and expressed through plant generations. Overproduction of flavonoid compounds resulted in increase of fatty acids accumulation in oil from transgenic seeds due to protection from oxidation offered during synthesis and seed maturation. The biochemical analysis of seedcake extracts from seeds of transgenic flax revealed significant increase in flavonoids (kaempferol, phenolic acids (coumaric, ferulic, synapic acids and lignan content. Fibres, another product of flax plant showed increase in the level of catechine and acetylvanillone and decrease in phenolic acids upon flax modification. Biochemical analysis results were confirmed using IR spectroscopy. The integral intensities of IR bands have been used for identification of the component of phenylpropanoid pathway in oil, seedcake extract and fibre from control and transgenic flax. It was shown that levels of flavonoids, phenolic acids and lignans in oil and seedcake extract was higher in transgenic flax products compared to control. An FT-IR study of fibres confirmed the biochemical data and revealed that the arrangement of the cellulose polymer in the transgenic fibres differs from the control; in particular a

  1. Aktivitas antibakteri flavonoid propolis Trigona sp terhadap bakteri Streptococcus mutans (in vitro (In vitro antibacterial activity of flavonoids Trigona sp propolis against Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Ardo Sabir

    2005-09-01

    Full Text Available A number of investigations have shown a positive correlation between the number of Streptococcus mutans (S. mutans in dental plaque and the prevalence of dental caries. Consequently, this microorganism has been the prime target for the prevention of dental caries. Propolis being a substance made by the honeybee, is a potent antibacterial agent. The main chemical class present in propolis is flavonoids. Flavonoids are well-known plant compounds that have antibacterial property. Because S. mutans is accepted to be one of the microorganisms responsible for dental caries and flavonoids in propolis are antibacterial, the purpose of this study was to evaluate in vitro the antibacterial activity of flavonoids Trigona sp propolis against S. mutans as a first step in its possible use as an alternative anticaries agent. Extract flavonoids was purified from ethanol extract of propolis which was obtained from Bulukumba Regency South Sulawesi using thin layer chromatography. The purification of flavonoids was carried-out by UVradiation at λ max 254 nm and λmax 366 nm and treatment with ammonia. Extract flavonoids was diluted in aquadest to 0.05%; 0.075%; 0.1%; 0.25%; 0.5%; 0.75% concentrations. Aquadest and 10% Povidone iodine were also used as control solution. S mutans were grown in medium glucose nutrient agar and incubated with flavonoids for 24 and 48 hours, at 37° C. Antibacterial activity was reflected by the diameter of the inhibition zones around the stainless steel cylinder. The data were analyzed by using ANOVA followed by LSD test with significance level of 5%. The results of this study showed that after being incubated for 24 and 48 hours, all flavonoid concentrations significantly (p < 0.05 inhibited the growth of S mutans. 0.1% flavonoid was the most effective concentration to inhibit the growth of S mutans after 24 hours of incubation and 0.5% flavonoid after 48 hours of incubator.

  2. Isomeric and high-spin states of 94Tc and the search for yrast isomers near Napprox.50

    International Nuclear Information System (INIS)

    Lee, I.Y.; Johnson, N.R.; McGowan, F.K.; Young, G.R.; Guidry, M.W.; Yates, S.W.

    1981-01-01

    A search for isomers in the Napprox.50 region has produced no evidence of high-spin yrast isomerism. A new 4.5-ns low-multiplicity isomer has been identified and assigned to 94 Tc, while the yrast sequence of 94 Tc has been established to more than 5 MeV in excitation energy

  3. Synthesis of Heterocycles through a Ruthenium‐Catalyzed Tandem Ring‐Closing Metathesis/Isomerization/N‐Acyliminium Cyclization Sequence

    DEFF Research Database (Denmark)

    Ascic, Erhad; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2011-01-01

    Tandem bicycle: In the title reaction double bonds created during ring-closing metathesis isomerize to generate reactive iminium intermediates that undergo intramolecular cyclization reactions with tethered heteroatom and carbon nucleophiles. In this way, a series of biologically interesting hete...... heterocyclic compounds can be made, including a known precursor for the total synthesis of the antiparasitic natural product harmicine....

  4. Ruthenium Stilbenyl and Diruthenium Distyrylethene Complexes: Aspects of Electron Delocalization and Electrocatalyzed Isomerization of the Z-Isomer

    Czech Academy of Sciences Publication Activity Database

    Linseis, M.; Záliš, Stanislav; Zabel, M.; Winter, R. F.

    2012-01-01

    Roč. 134, č. 40 (2012), s. 16671-16692 ISSN 0002-7863 R&D Projects: GA MŠk LD11086 Institutional support: RVO:61388955 Keywords : CIS-TRANS-ISOMERIZATION * MIXED-VALENCE COMPOUNDS * VIBRATIONAL TIME -SCALE Subject RIV: CG - Electrochemistry Impact factor: 10.677, year: 2012

  5. Valence isomerization of 2-phospha-4-silabicyclo[1.1.0]butane: a high-level ab initio study

    NARCIS (Netherlands)

    Slootweg, J.C.; Ehlers, A.W.; Lammertsma, K.

    2006-01-01

    The rearrangements for 2-phospha-4-silabicyclo[1.1.0]butane, analogous to the valence isomerization of the hydrocarbons bicyclobutane, 1,3-butadiene, and cyclobutene, were studied at the (U)QCISD(T)/ 6-311+G**//(U)QCISD/6-31G* level of theory. The monocyclic 1,2-dihydro-1,2-phosphasiletes are shown

  6. Measurements of 14-MeV neutron cross-sections for the production of isomeric states in hafnium isotopes

    International Nuclear Information System (INIS)

    Patrick, B.H.; Sowerby, M.G.; Wilkins, C.G.; Russen, L.C.

    1990-01-01

    The cross sections for the production of isomeric states in the reactions 179 Hf(n,2n) 178m2 Hf, 180 Hf(n,2n) 179m2 Hf, 179 Hf(n,n') 179m2 Hf with 14 MeV neutrons have been measured and compared with the theoretical ones. 4 refs, 3 figs, 4 tabs

  7. Anion-assisted trans-cis isomerization of palladium(II) phosphine complexes containing acetanilide functionalities through hydrogen bonding interactions.

    Science.gov (United States)

    Lu, Xiao-Xia; Tang, Hau-San; Ko, Chi-Chiu; Wong, Jenny Ka-Yan; Zhu, Nianyong; Yam, Vivian Wing-Wah

    2005-03-28

    The anion-assisted shift of trans-cis isomerization equilibrium of a palladium(II) complex containing acetanilide functionalities brought about by allosteric hydrogen bonding interactions has been established by UV/Vis, 1H NMR, 31P NMR and ESI-MS studies.

  8. Investigation of the interaction between isomeric derivatives and human serum albumin by fluorescence spectroscopy and molecular modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruiyong, E-mail: wangry@zzu.edu.cn; Dou, Huanjing; Yin, Yujing; Xie, Yuanzhe; Sun, Li; Liu, Chunmei; Dong, Jingjing; Huang, Gang; Zhu, Yanyan; Song, Chuanjun, E-mail: chjsong@zzu.edu.cn; Chang, Junbiao, E-mail: changjunbiao@zzu.edu.cn

    2014-10-15

    In this paper, we have synthesized 9H-pyrrolo[1,2-a]indol-9-ones and the isomeric indeno[2,1-b]pyrrol-8-ones. The interactions of human serum albumin with series of isomeric derivatives have been studied by spectrophotometric methods. Results show the intrinsic fluorescence is quenched by the derivatives with a static quenching procedure. The thermodynamics parameters indicate that van der Waals forces and hydrogen bonds play a major role in the interactions. The results of synchronous fluorescence spectra demonstrate that the microenvironments of Trp residue of human serum albumin are disturbed by most derivatives. Thermodynamic results showed that the 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers and bind to human serum albumin with the higher affinity than isomeric indeno[2,1-b]pyrrol-8-ones. The influence of molecular structure on the binding aspects has been investigated. - Highlights: • The interactions between isomeric derivatives and HSA have been investigated. • Results reveal that 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers for HSA. • Hydrogen bonds and van der Waals forces play major role in the binding process. • The influence of molecular structure on the binding aspects has been investigated. • The binding study was also modeled by molecular docking.

  9. Investigation of the interaction between isomeric derivatives and human serum albumin by fluorescence spectroscopy and molecular modeling

    International Nuclear Information System (INIS)

    Wang, Ruiyong; Dou, Huanjing; Yin, Yujing; Xie, Yuanzhe; Sun, Li; Liu, Chunmei; Dong, Jingjing; Huang, Gang; Zhu, Yanyan; Song, Chuanjun; Chang, Junbiao

    2014-01-01

    In this paper, we have synthesized 9H-pyrrolo[1,2-a]indol-9-ones and the isomeric indeno[2,1-b]pyrrol-8-ones. The interactions of human serum albumin with series of isomeric derivatives have been studied by spectrophotometric methods. Results show the intrinsic fluorescence is quenched by the derivatives with a static quenching procedure. The thermodynamics parameters indicate that van der Waals forces and hydrogen bonds play a major role in the interactions. The results of synchronous fluorescence spectra demonstrate that the microenvironments of Trp residue of human serum albumin are disturbed by most derivatives. Thermodynamic results showed that the 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers and bind to human serum albumin with the higher affinity than isomeric indeno[2,1-b]pyrrol-8-ones. The influence of molecular structure on the binding aspects has been investigated. - Highlights: • The interactions between isomeric derivatives and HSA have been investigated. • Results reveal that 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers for HSA. • Hydrogen bonds and van der Waals forces play major role in the binding process. • The influence of molecular structure on the binding aspects has been investigated. • The binding study was also modeled by molecular docking

  10. Nitrite-reductase and peroxynitrite isomerization activities of Methanosarcina acetivorans protoglobin.

    Directory of Open Access Journals (Sweden)

    Paolo Ascenzi

    Full Text Available Within the globin superfamily, protoglobins (Pgb belong phylogenetically to the same cluster of two-domain globin-coupled sensors and single-domain sensor globins. Multiple functional roles have been postulated for Methanosarcina acetivorans Pgb (Ma-Pgb, since the detoxification of reactive nitrogen and oxygen species might co-exist with enzymatic activity(ies to facilitate the conversion of CO to methane. Here, the nitrite-reductase and peroxynitrite isomerization activities of the CysE20Ser mutant of Ma-Pgb (Ma-Pgb* are reported and analyzed in parallel with those of related heme-proteins. Kinetics of nitrite-reductase activity of ferrous Ma-Pgb* (Ma-Pgb*-Fe(II is biphasic and values of the second-order rate constant for the reduction of NO2- to NO and the concomitant formation of nitrosylated Ma-Pgb*-Fe(II (Ma-Pgb*-Fe(II-NO are k(app1= 9.6 ± 0.2 M(-1 s(-1 and k(app2 = 1.2 ± 0.1 M(-1 s(-1 (at pH 7.4 and 20 °C. The k(app1 and k(app2 values increase by about one order of magnitude for each pH unit decrease, between pH 8.3 and 6.2, indicating that the reaction requires one proton. On the other hand, kinetics of peroxynitrite isomerization catalyzed by ferric Ma-Pgb* (Ma-Pgb*-Fe(III is monophasic and values of the second order rate constant for peroxynitrite isomerization by Ma-Pgb*-Fe(III and of the first order rate constant for the spontaneous conversion of peroxynitrite to nitrate are h(app = 3.8 × 10(4 M(-1 s(-1 and h0 = 2.8 × 10(-1 s(-1 (at pH 7.4 and 20 °C. The pH-dependence of hon and h0 values reflects the acid-base equilibrium of peroxynitrite (pKa = 6.7 and 6.9, respectively; at 20 °C, indicating that HOONO is the species that reacts preferentially with the heme-Fe(III atom. These results highlight the potential role of Pgbs in the biosynthesis and scavenging of reactive nitrogen and oxygen species.

  11. Flavonoides glicosilados de Erythroxylum pulchrum a. st.-hil. (Erythroxylaceae

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    Camila Holanda de Albuquerque

    2014-01-01

    Full Text Available The phytochemical investigation of Erythroxylum pulchrum St. Hil. (Erythroxylaceae led to the isolation of three known flavonoid glycosides quercetin-3-O-α-L-rhaminoside, ombuin-3-ruthinoside and ombuin-3-ruthinoside-5-glucoside. These flavonoids are being described for the first time in this E. pulchrum. The structures of the compounds were determined by analysis of IR, MS and NMR data, as well as by comparison with literature data. The methanolic extract of leaves from E. pulchrum inhibited the growth of the Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, P. aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, S. aureus ATCC 25925, Streptococcus sanguinis ATCC 15300, S. salivarius ATCC 7073, S. mutans ATCC 25175 and Streptococcus ATCC. S. aureus ATCC 25925 was the most sensitive among the other S. sanguinis while S. salivarius proved the most resistant.

  12. Flavonoid glycosides from Erythroxylum pulchrum A. St.-Hil. (Erythroxylaceae)

    International Nuclear Information System (INIS)

    Albuquerque, Camila Holanda de; Tavares, Josean Fechine; Oliveira, Steno Lacerda de; Silva, Taina Souza; Costa, Vicente Carlos de Oliveira; Silva, Marcelo Sobral da; Goncalves, Gregorio Fernandes; Pessoa, Hilzeth de Luna Freire; Agra, Maria de Fatima

    2014-01-01

    The phytochemical investigation of Erythroxylum pulchrum St. Hil. (Erythroxylaceae) led to the isolation of three known flavonoid glycosides quercetin-3-O-α-L-rhaminoside, ombuin-3-ruthinoside and ombuin-3-ruthinoside-5-glucoside. These flavonoids are being described for the first time in this E. pulchrum. The structures of the compounds were determined by analysis of IR, MS and NMR data, as well as by comparison with literature data. The methanolic extract of leaves from E. pulchrum inhibited the growth of the Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, P. aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, S. aureus ATCC 25925, Streptococcus sanguinis ATCC 15300, S. salivarius ATCC 7073, S. mutans ATCC 25175 and Streptococcus ATCC. S. aureus ATCC 25925 was the most sensitive among the other S. sanguinis while S. salivarius proved the most resistant. (author)

  13. PHYSIOLOGICAL AND MEDICAL EFFECTS OF PLANT FLAVONOID QUERCETIN

    Directory of Open Access Journals (Sweden)

    Aneta Štochmaľová

    2013-02-01

    Full Text Available Flavonoid compounds in vegetable-based diets bring a significant contribution to the role of fruits and vegetables as health-promoting foods. This review summarizes the available data concerning physiological and therapeutical effect of plan flavonoid quercetin. Quercetin has a number of beneficial influence on health because of their antioxidant, anti-inflammatory, anti-proliferative, anti-carcinogenic and anti-diabetes properties. Effects of quercetin have been explained by its interference with cellular enzymes, receptors, transporters and signal transduction systems. Despite the available data reviewed here, the targets, effects, absorption, metabolism and areas of practical application of quercetin are still poorly understood, therefore further studies in this areas are required.

  14. Antiproliferative activity of flavonoids on several cancer cell lines.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

    1999-05-01

    Twenty-seven Citrus flavonoids were examined for their antiproliferative activities against several tumor and normal human cell lines. As a result, 7 flavonoids were judged to be active against the tumor cell lines, while they had weak antiproliferative activity against the normal human cell lines. The rank order of potency was luteolin, natsudaidain, quercetin, tangeretin, eriodictyol, nobiletin, and 3,3',4',5,6,7,8-heptamethoxyflavone. The structure-activity relationship established from comparison among these flavones and flavanones showed that the ortho-catechol moiety in ring B and a C2-C3 double bond were important for the antiproliferative activity. As to polymethoxylated flavones, C-3 hydroxyl and C-8 methoxyl groups were essential for high activity.

  15. Flavonoids and fatty acids of Camellia japonica leaves extract

    Directory of Open Access Journals (Sweden)

    Cinthia M. Azuma

    2011-07-01

    Full Text Available The ethanol extract from the leaves of Camellia japonica L., Theaceae, showed antiradical potential in the DPPH test using TLC plates (SiO2. Aiming the isolation of active compounds, this extract was partitioned between BuOH:H2O (1:1 and the two obtained phases were also evaluated to detection of antiradical activity. The active BuOH phase was fractionated in Sephadex LH-20 and silica (normal or reverse phase to afford three aglycone flavonoids (quercetin, kaempferol and apigenin, which have been described in the C. japonica at first time, two glycosilated flavonoids (rutin and quercetrin, and a mixture of saturated fatty acids. The structures of isolated compounds were defined by NMR and GC/MS analyses.

  16. Flavonoids and fatty acids of Camellia japonica leaves extract

    Directory of Open Access Journals (Sweden)

    Cinthia M. Azuma

    2011-12-01

    Full Text Available The ethanol extract from the leaves of Camellia japonica L., Theaceae, showed antiradical potential in the DPPH test using TLC plates (SiO2. Aiming the isolation of active compounds, this extract was partitioned between BuOH:H2O (1:1 and the two obtained phases were also evaluated to detection of antiradical activity. The active BuOH phase was fractionated in Sephadex LH-20 and silica (normal or reverse phase to afford three aglycone flavonoids (quercetin, kaempferol and apigenin, which have been described in the C. japonica at first time, two glycosilated flavonoids (rutin and quercetrin, and a mixture of saturated fatty acids. The structures of isolated compounds were defined by NMR and GC/MS analyses.

  17. Contenido de flavonoides y compuestos fenólicos de mieles chilenas e índice antioxidante Content of flavonoids and phenolic compounds in chilean honeys. Orac index

    Directory of Open Access Journals (Sweden)

    Orlando Muñoz

    2007-08-01

    Full Text Available A comparison of the phenolic content of several Chilean honeys showed great variations in flavonoid concentration among the samples analysed. Higher amounts of phenolics are found in honey from dry climates. The antioxidant effect of extracts, using ORAC analysis, did not correlate with the flavonoid content or with the total phenolic concentration.

  18. Phytochemical study of the flavonoids of acacia nilotica var astringens

    International Nuclear Information System (INIS)

    El Gazali, N. A.

    2006-08-01

    The barks of acaica nilotica var astringens were extracted with 95% ethanol. Qualitative tests on the alcoholic extractives were negative for alkaloids and positive for steroids, tannins and flavonoids. Fractionation of the alcoholic extract over silica gel using acetone: methanol (4:1) gave a pure compound-compound 1. The structure of compound 1 was deduced on the basis of its IR, UV, NMR and mass spectra and the following structure was suggested.(Author)

  19. The oxidation of luteolin, the natural flavonoid dye

    Czech Academy of Sciences Publication Activity Database

    Ramešová, Šárka; Sokolová, Romana; Tarábek, Ján; Degano, I.

    2013-01-01

    Roč. 110, NOV 2013 (2013), s. 646-654 ISSN 0013-4686 R&D Projects: GA ČR GA203/09/1607 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M200401201 Program:M Institutional support: RVO:61388955 ; RVO:61388963 Keywords : oxidation * flavonoids * luteolin Subject RIV: CG - Electrochemistry Impact factor: 4.086, year: 2013

  20. Effect of precursors on flavonoid production by Hydrocotyle ...

    African Journals Online (AJOL)

    Callus tissue of Hydrocotyle bonariensis was initiated from the leaf of H. bonariensis treated with 2 mg/l of 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg/l kinetin. The culture was kept at 25°C, under light (cool white fluorescent tubes, 1200 lux). To optimize the precursors to increase the production of flavonoid, different ...

  1. Flavonoids in the leaves of Asclepias incarnata L.

    Science.gov (United States)

    Sikorska, Maria

    2003-01-01

    Seven flavonoid compounds: quercelin 3-O-beta-galactopyranoside, 3-O-beta-glucopyranoside, 3-O-arabinoside, 3-O-beta-glucopyranosyl (1-->2)-beta-galactopyranoside, 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside, 3-O-alpha-rhamnopyranosyl (1-->2)-beta-galactopyranoside and kaempferol 3-beta-glucopyranoside were isolated and identified from the leaves of Asclepias incarnata, L. (Asclepiadaceae).

  2. FUNCTIONAL SPECIALIZATION OF DUPLICATED FLAVONOID BIOSYNTHESIS GENES IN WHEAT

    Directory of Open Access Journals (Sweden)

    Khlestkina E.

    2012-08-01

    Full Text Available Gene duplication followed by subfunctionalization and neofunctionalization is of a great evolutionary importance. In plant genomes, duplicated genes may result from either polyploidization (homoeologous genes or segmental chromosome duplications (paralogous genes. In allohexaploid wheat Triticum aestivum L. (2n=6x=42, genome BBAADD, both homoeologous and paralogous copies were found for the regulatory gene Myc encoding MYC-like transcriptional factor in the biosynthesis of flavonoid pigments, anthocyanins, and for the structural gene F3h encoding one of the key enzymes of flavonoid biosynthesis, flavanone 3-hydroxylase. From the 5 copies (3 homoeologous and 2 paralogous of the Myc gene found in T. aestivum, only one plays a regulatory role in anthocyanin biosynthesis, interacting complementary with another transcriptional factor (MYB-like to confer purple pigmentation of grain pericarp in wheat. The role and functionality of the other 4 copies of the Myc gene remain unknown. From the 4 functional copies of the F3h gene in T. aestivum, three homoeologues have similar function. They are expressed in wheat organs colored with anthocyanins or in the endosperm, participating there in biosynthesis of uncolored flavonoid substances. The fourth copy (the B-genomic paralogue is transcribed neither in wheat organs colored with anthocyanins nor in seeds, however, it’s expression has been noticed in roots of aluminium-stressed plants, where the three homoeologous copies are not active. Functional diversification of the duplicated flavonoid biosynthesis genes in wheat may be a reason for maintenance of the duplicated copies and preventing them from pseudogenization.The study was supported by RFBR (11-04-92707. We also thank Ms. Galina Generalova for technical assistance.

  3. Microbial production of the flavonoids garbanzol, resokaempferol and fisetin

    OpenAIRE

    Stahlhut, Steen Gustav; Siedler, Solvej; Neves, Ana Rute; MAURY,, JEROME; Förster, Jochen; Gaspar, Paula; Borodina, Irina; Rodriguez Prado, Edith Angelica; Strucko, Tomas

    2016-01-01

    The invention provides a genetically modified micro-organism comprising one or more transgene for the production of one or more of the flavonoids garbanzol, resokaempferol and fisetin. The micro-organism may be a bacterial or yeast cell engineered to express a metabolic pathway for garbanzol, resokaempferol and/or fisetin biosynthesis. The invention further provides a method for producing garbanzol, resokaempferol and/or fisetin employing the genetically modified micro-organism of the inventi...

  4. Citrus Flavonoid Supplementation Improves Exercise Performance in Trained Athletes

    Directory of Open Access Journals (Sweden)

    Elvera Overdevest, Jeroen A. Wouters, Kevin H.M. Wolfs, Job J.M. van Leeuwen, Sam Possemiers

    2018-03-01

    Full Text Available Previous studies have shown that polyphenol supplementation may be an effective strategy to improve exercise performance, due to their antioxidant character and ability to stimulate NO production. These properties may contribute to exercise performance, yet no conclusive research has been performed in exploring the direct effects of citrus flavonoids on human exercise performance. Therefore, the purpose of this study was to assess whether supplementation of a customized citrus flavonoid (CF extract for 4 weeks improves cycling time-trial performance in trained male athletes. In a double-blind, randomized, parallel study, 39 healthy, trained males were given a daily dose of either 500 mg of a customized citrus flavonoid extract (CF or a placebo for 4 weeks. Exercise performance was tested by means of a time-trial test on a cycle ergometer, during which participants had to generate as much power as possible for duration of 10 minutes. Absolute power output significantly increased with 14.9 ± 3.9 W after 4 weeks of CF supplementation, corresponding with a 5.0% increase, compared to 3.8 ± 3.2 W (1.3% increase in placebo (p < 0.05. In addition, oxygen consumption/power ratio significantly decreased in the CF group compared to placebo (p = 0.001, and a trend was found in the change in peak power output in CF (18.2 ± 23.2 W versus placebo (-28.4 ± 17.6 W; p = 0.116. The current study is the first convincing report that citrus flavonoid supplementation can improve exercise performance, as shown by a significant increase in power output during the exercise test.

  5. Flavonoids from the flowers of Nymphaea alba L.

    Directory of Open Access Journals (Sweden)

    Jerzy Jambor

    2014-01-01

    Full Text Available Ten flavonoids were obtained from the flowers of Nymphaea alba L. Their structures were determined mainly on the basis of spectral analyses (UV, 'H NMR, MS. The following aglycons were isolated: quercetin, kaempferol, isokaempferide and apigenin as well as the following glycosides: quercetion 4'-β-xyloside, 3-methylquercetin 3'-β-xyloside and a mixture of quercetin 3-galactoside and 3-glucoside. The structures of three compounds obtained in very small amounts were determined in part.

  6. Exploring the molecular targets of dietary flavonoid fisetin in cancer

    OpenAIRE

    Syed, Deeba N.; Adhami, Vaqar Mustafa; Khan, Naghma; Khan, Mohammad Imran; Mukhtar, Hasan

    2016-01-01

    The last few decades have seen a resurgence of interest among the scientific community in exploring the efficacy of natural compounds against various human cancers. Compounds of plant origin belonging to different groups such as alkaloids, flavonoids and polyphenols evaluated for their cancer preventive effects have yielded promising data, thereby offering a potential therapeutic alternative against this deadly disease. The flavonol fisetin (3,3′,4′,7-tetrahydroxyflavone), present in fruits a...

  7. Mutagenicity of Flavonoids Assayed by Bacterial Reverse Mutation (Ames Test

    Directory of Open Access Journals (Sweden)

    Eliana Aparecida Varanda

    2012-05-01

    Full Text Available The mutagenicity of ten flavonoids was assayed by the Ames test, in Salmonella typhimurium strains TA98, TA100 and TA102, with the aim of establishing hydroxylation pattern-mutagenicity relationship profiles. The compounds assessed were: quercetin, kaempferol, luteolin, fisetin, chrysin, galangin, flavone, 3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone. In the Ames assay, quercetin acted directly and its mutagenicity increased with metabolic activation. In the presence of S9 mix, kaempferol and galangin were mutagenic in the TA98 strain and kaempferol showed signs of mutagenicity in the other strains. The absence of hydroxyl groups, as in flavone, only signs of mutagenicity were shown in strain TA102, after metabolization and, among monohydroxylated flavones (3-hydroxyflavone, 5-hydroxyflavone and 7-hydroxyflavone, the presence of hydroxyl groups only resulted in minor changes. Luteolin and fisetin also showed signs of mutagenicity in strain TA102. Finally, chrysin, which has only two hydroxy groups, at the 5-OH and 7-OH positions, also did not induce mutagenic activity in any of the bacterial strains used, under either activation condition. All the flavonoids were tested at concentrations varying from 2.6 to 30.7 nmol/plate for galangin and 12.1 to 225.0 nmol/plate for other flavonoids. In light of the above, it is necessary to clarify the conditions and the mechanisms that mediate the biological effects of flavonoids before treating them as therapeutical agents, since some compounds can be biotransformed into more genotoxic products; as is the case for galangin, kaempferol and quercetin.

  8. Analysis of Flavonoids in Rhamnus davurica and Its Antiproliferative Activities

    Directory of Open Access Journals (Sweden)

    Guilin Chen

    2016-09-01

    Full Text Available Rhamnus davurica Pall. (R. davurica has been used as a traditional medicinal herb for many years in China and abroad. It has been well documented as a rich source of flavonoids with diversified structures, which in turn results in far-ranging biological activities, such as anti-inflammation, anticancer, antibacterial and antioxidant activities. In order to further correlate their anticancer potentials with the phytochemical components, the fingerprint profile of R. davurica herb from Dongbei was firstly investigated using HPLC-ESI-MS/MS. Thirty two peaks were detected and identified, 14 of which were found in R. davurica for the first time in this work. Furthermore, a total of 23 peaks were resolved as flavonoids, which are the major components found in R. davurica. Meanwhile, the antiproliferative activities against human cancer cells of HT-29 and SGC-7901 in vitro exhibited distinct inhibitory effects with IC50 values at 24.96 ± 0.74 and 89.53 ± 4.11 μg/mL, respectively. Finally, the general toxicity against L-O2 cells displayed a much higher IC50 at 229.19 ± 8.52 μg/mL, which suggested very low or no toxicity on hepatic cell viability. The current study revealed for the first time the correlations between the flavonoids of R. davurica with their antiproliferative activities, which indicated that the fingerprint profile of flavonoids and their anticancer activities could provide valuable information on the quality control for herbal medicines and their derived natural remedies from this valuable medicinal plant.

  9. Promotion of selective pathways in isomerizing functionalization of plant oils by rigid framework substituents

    KAUST Repository

    Christl, Josefine T.

    2014-10-14

    The 1,2-(CH2P(1-adamantyl)2)2C6H4 (dadpx) coordinated palladium complex [(dadpx)Pd(OTf)2] (1) is a catalyst precursor for the isomerizing methoxycarbonylation of the internal double bond of methyl oleate, with an unprecedented selectivity (96%) for the linear diester 1,19-dimethyl nonadecanedioate. Rapid formation of the catalytically active solvent-coordinated hydride species [(dadpx)PdH(MeOH)]+ (3-MeOH) is evidenced by NMR spectroscopy, and further isolation and X-ray crystal structure analysis of [(dadpx)PdH(PPh3)]+ (3-PPh3). DFT calculations of key steps of the catalytic cycle unravel methanolysis as the decisive step for enhanced selectivity and the influence of the rigid adamantyl framework on this step by destabilization of transition states of unselective pathways.

  10. Characterization of Isomeric Glycans by Reversed Phase Liquid Chromatography-Electronic Excitation Dissociation Tandem Mass Spectrometry

    Science.gov (United States)

    Tang, Yang; Wei, Juan; Costello, Catherine E.; Lin, Cheng

    2018-04-01

    The occurrence of numerous structural isomers in glycans from biological sources presents a severe challenge for structural glycomics. The subtle differences among isomeric structures demand analytical methods that can provide structural details while working efficiently with on-line glycan separation methods. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool for mixture analysis, the commonly utilized collision-induced dissociation (CID) method often does not generate a sufficient number of fragments at the MS2 level for comprehensive structural characterization. Here, we studied the electronic excitation dissociation (EED) behaviors of metal-adducted, permethylated glycans, and identified key spectral features that could facilitate both topology and linkage determinations. We developed an EED-based, nanoscale, reversed phase (RP)LC-MS/MS platform, and demonstrated its ability to achieve complete structural elucidation of up to five structural isomers in a single LC-MS/MS analysis. [Figure not available: see fulltext.

  11. Antifungal activity and isomerization of octadecyl p-coumarates from Ipomoea carnea subsp. fistulosa.

    Science.gov (United States)

    Nidiry, Eugene Sebastian J; Ganeshan, Girija; Lokesha, Ankanahalli N

    2011-12-01

    Bioassay monitored HPLC assisted isolation and purification of the chief antifungal fraction of the leaves of Ipomoea carnea subsp. fistulosa (Convulvulaceae) were achieved using Colletotrichum gloeosporioides and Cladosporium cucumerinum as test organisms. The activity of the purified fraction was further confirmed by the dose dependent inhibition of the spore germination of Alternaria alternata and A. porri. The active fraction was identified as a mixture of (E)-octadecyl p-coumarate and (Z)-octadecyl p-coumarate. The two isomers were detected on an HPLC column with substantially different retention times, but once eluted from the column, one form was partly converted to the other in daylight. Conclusive evidence for the structures and their isomerization were obtained from the HPLC behavior, IR, UV, HRESIMS, CIMS and and NMR spectral data. Important 1H NMR and 13C NMR signals could be separately assigned for the isomers using 2D NMR techniques.

  12. Analysis of carboxylate coordination function of the isomeric lanthanide pyridinedicarboxylates by means of vibration spectroscopy

    International Nuclear Information System (INIS)

    Puntus, L.; Zolin, V.; Kudryashova, V.

    2004-01-01

    The investigation of IR spectra of salts of six isomers of pyridinedicarboxylic acid (PDA): 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-pyridinedicarboxylic acids, have demonstrated that properties of these salts are dependent on the bonding manner of carboxylate groups and on coordination of heterocyclic nitrogen atom. The most prominent differences in properties and spectra of 2,6- and 3,4-PDA salts are conditioned correspondingly by monodentate and bidentate coordination functions of the carboxylate groups in these compounds. The correlation of the breathing vibration frequency, reflecting the rigidity of the heterocyclic ring, with position of the carboxylate substituents, conditioning intramolecular charge transfer (CT), was postulated and proved by shifts of the breathing vibration frequency dependent on the structure of isomeric ligand

  13. A quest for staunch effects of flavonoids: Utopian protection against hepatic ailments

    Directory of Open Access Journals (Sweden)

    Anju Dhiman

    2016-11-01

    Full Text Available The role of flavonoids as the major red, blue and purple pigments in plants has gained these secondary products a great deal of attention over the years. Flavonoids are polyphenols and occur as aglycones, glycosides and methylated derivatives. Flavonoids are the main components of a healthy diet containing fruits and vegetables and are concentrated especially in tea, apples and onions. Till date, more than 6000 flavonoids have been discovered, out of which 500 are found in free state. They are abundant in polygonaceae, rutaceae, leguminosae, umbelliferae and compositae. Flavonoids are powerful antioxidants. In addition to their role in nutrition, flavonoids possess many types of pharmacological activities, including anti-inflammatory, antioxidative, hepatoprotective, vasorelaxant, antiviral and anticarcinogenic effects. The present review is focused on flavonoids derived from natural products that have shown a wise way to get a true and potentially rich source of drug candidates against liver ailments. The present review initially highlights the current status of flavonoids and their pharmaceutical significance, role of flavonoids in hepatoprotection, therapeutic options available in herbal medicines and in later section, summarizes flavonoids as lead molecules, which have shown significant hepatoprotective activities.

  14. Influence of Intestinal Microbiota on the Catabolism of Flavonoids in Mice.

    Science.gov (United States)

    Lin, Weiqun; Wang, Wenting; Yang, Hai; Wang, Dongliang; Ling, Wenhua

    2016-12-01

    Although in vitro studies have shown that flavonoids are metabolized into phenolic acids by the gut microbiota, the biotransformation of flavonoids by intestinal microbiota is seldom studied in vivo. In this study, we investigated the impact of the gut microbiota on the biotransformation of 3 subclasses of flavonoids (flavonols, flavones, and flavanones). The ability of intestinal microbiota to convert flavonoids was confirmed with an in vitro fermentation model using mouse gut microflora. Simultaneously, purified flavonoids were administered to control and antibiotic-treated mice by gavage, and the metabolism of these flavonoids was evaluated. p-Hydroxyphenylacetic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, hydrocaffeic acid, coumaric acid, and 3-(4-hydroxyphenyl)propionic acid were detected in the serum samples from the control mice after flavonoid consumption. The serum flavonoid concentrations were similar in both groups, whereas the phenolic metabolite concentrations were lower in the antibiotic-treated mice than in the control mice. We detected markedly higher flavonoids excretion in the feces and urine of the antibiotic-treated mice compared to the controls. Moreover, phenolic metabolites were upregulated in the control mice. These results suggest that the intestinal microbiota are not necessary for the absorption of flavonoids, but are required for their transformation. © 2016 Institute of Food Technologists®.

  15. Identification and quantification and antioxidant activity of flavonoids in different strains of silk cocoon, Bombyx mori.

    Science.gov (United States)

    Napavichayanun, Supamas; Lutz, Oliver; Fischnaller, Martin; Jakschitz, Thomas; Bonn, Günther; Aramwit, Pornanong

    2017-10-01

    Silk cocoon is produced from silkworm (Bombyx mori) to protect itself from outer environment. Various strains of cocoon contain different forms and amounts of flavonoids, which may affect on their antioxidant activity. Moreover, the extraction method would influence the amount of flavonoids extracted. Therefore, the objectives of this study were to identify and quantify the flavonoids in 3 strains of bivoltine Bombyx mori silk cocoon (Chul 1/1; white cocoon, Chul 3/2; greenish cocoon, and Chul 4/2; yellow cocoon) extracted by 6 different solvents including acetone, ethyl acetate, dimethyl sulfoxide (DMSO), ethanol, methanol, and purified water. The flavonoids extracted were identified and quantified by liquid chromatography-mass spectrometry (LC-MS). The antioxidant activity of flavonoids extracted was also investigated by visible spectroscopy at 517 nm. The results showed that Chul 3/2 silk cocoon contained the highest amount of flavonoids. Purified water seemed to be the best solvent that preserved most antioxidant activity of the flavonoids extracted. Flavonoids in Chul 1/1 and Chul 4/2 silk cocoon were rarely found, however they contained some antioxidant activities. The data from this study can provide basic information for flavonoid extraction from silk cocoon which can also apply for other flavonoid-containing natural biomaterials. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Electrochemical study of the increased antioxidant capacity of flavonoids through complexation with iron(II) ions

    International Nuclear Information System (INIS)

    Porfírio, Demóstenes Amorim; Ferreira, Rafael de Queiroz; Malagutti, Andréa Renata; Valle, Eliana Maíra Agostini

    2014-01-01

    Highlights: • Metal-Flavonoid complexes exhibit greater antioxidant capacity than the free flavonoid;. • Voltammetric profile is an additional information for determining antioxidant capacity;. • Pyrogallol group is a stronger complex-forming group than the catechol;. • Morin, quercetin and fisetin increased their antioxidant capacity in 15%, 32% and 28%, respectively. - Abstract: Flavonoids are polyphenolic compounds that act as natural antioxidants in the human body through various mechanisms, with an emphasis on suppressing reactive oxygen species (ROS) formation by inhibiting enzymes, the direct capture of ROS, and the regulation/protection of antioxidant defenses. Additionally, flavonoids can coordinate with transition metals to catalyze electron transport and promote free radical capture. Recently, metal ion chelation mechanisms have generated considerable interest, as experimental data show that flavonoids in metal complexes exhibit greater antioxidant activity than free flavonoids. However, few studies have correlated the complexing properties of flavonoids with their antioxidant capacity. Thus, the aim of this study was to use the CRAC (Ceric Reducing Antioxidant Capacity) electrochemical assay to measure the antioxidant capacity of five free flavonoids and Fe 2+ -flavonoid complexes. In addition, the interactions between the flavonoids and Fe 2+ were analyzed based on the oxidation peaks formed in their cyclic voltammograms

  17. Dietary flavonoid derivatives enhance chemotherapeutic effect by inhibiting the DNA damage response pathway

    International Nuclear Information System (INIS)

    Kuo, Ching-Ying; Zupkó, István; Chang, Fang-Rong; Hunyadi, Attila; Wu, Chin-Chung; Weng, Teng-Song; Wang, Hui-Chun

    2016-01-01

    Flavonoids are the most common group of polyphenolic compounds and abundant in dietary fruits and vegetables. Diet high in vegetables or dietary flavonoid supplements is associated with reduced mortality rate for patients with breast cancer. Many studies have been proposed for mechanisms linking flavonoids to improving chemotherapy efficacy in many types of cancers, but data on this issue is still limited. Herein, we report on a new mechanism through which dietary flavonoids inhibit DNA damage checkpoints and repair pathways. We found that dietary flavonoids could inhibit Chk1 phosphorylation and decrease clonogenic cell growth once breast cancer cells receive ultraviolet irradiation, cisplatin, or etoposide treatment. Since the ATR-Chk1 pathway mainly involves response to DNA replication stress, we propose that flavonoid derivatives reduce the side effect of chemotherapy by improving the sensitivity of cycling cells. Therefore, we propose that increasing intake of common dietary flavonoids is beneficial to breast cancer patients who are receiving DNA-damaging chemotherapy, such as cisplatin or etoposide-based therapy. - Highlights: • First report on inhibition of both DNA damage and repair by dietary flavonoids • Dietary flavonoids inhibit cisplatin- and UV-induced Chk1 phosphorylation. • Flavonoids combined with cisplatin or UV treatment show notable growth inhibition. • Promising treatment proposal for patients who are receiving adjuvant chemotherapy

  18. Dietary flavonoid derivatives enhance chemotherapeutic effect by inhibiting the DNA damage response pathway

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Ching-Ying [Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Zupkó, István [Department of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös Utca 6, Szeged H-6720 (Hungary); Chang, Fang-Rong [Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Hunyadi, Attila [Institute of Pharmacognosy, Faculty of Pharmacy, University of Szeged, Eötvös Utca 6, Szeged H-6720 (Hungary); Wu, Chin-Chung; Weng, Teng-Song [Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Wang, Hui-Chun, E-mail: wanghc@kmu.edu.tw [Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); PhD Program in Translational Medicine, College of Medicine and PhD Program in Toxicology, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Research Center for Natural Product and Drug Development, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Translational Research Center and Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung 80756, Taiwan (China); Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China)

    2016-11-15

    Flavonoids are the most common group of polyphenolic compounds and abundant in dietary fruits and vegetables. Diet high in vegetables or dietary flavonoid supplements is associated with reduced mortality rate for patients with breast cancer. Many studies have been proposed for mechanisms linking flavonoids to improving chemotherapy efficacy in many types of cancers, but data on this issue is still limited. Herein, we report on a new mechanism through which dietary flavonoids inhibit DNA damage checkpoints and repair pathways. We found that dietary flavonoids could inhibit Chk1 phosphorylation and decrease clonogenic cell growth once breast cancer cells receive ultraviolet irradiation, cisplatin, or etoposide treatment. Since the ATR-Chk1 pathway mainly involves response to DNA replication stress, we propose that flavonoid derivatives reduce the side effect of chemotherapy by improving the sensitivity of cycling cells. Therefore, we propose that increasing intake of common dietary flavonoids is beneficial to breast cancer patients who are receiving DNA-damaging chemotherapy, such as cisplatin or etoposide-based therapy. - Highlights: • First report on inhibition of both DNA damage and repair by dietary flavonoids • Dietary flavonoids inhibit cisplatin- and UV-induced Chk1 phosphorylation. • Flavonoids combined with cisplatin or UV treatment show notable growth inhibition. • Promising treatment proposal for patients who are receiving adjuvant chemotherapy.

  19. Identification of a flavonoid C-glycoside as potent antioxidant.

    Science.gov (United States)

    Wen, Lingrong; Zhao, Yupeng; Jiang, Yueming; Yu, Limei; Zeng, Xiaofang; Yang, Jiali; Tian, Miaomiao; Liu, Huiling; Yang, Bao

    2017-09-01

    Flavonoids have been documented to have good antioxidant activities in vitro. However, reports on the cellular antioxidant activities of flavonoid C-glycosides are very limited. In this work, an apigenin C-glycoside was purified from Artocarpus heterophyllus by column chromatography and was identified to be 2″-O-β-D-xylosylvitexin by nuclear magnetic resonance spectroscopy. The cellular antioxidant activity and anticancer activity of 2″-O-β-D-xylosylvitexin were evaluated for the first time. The quantitative structure-activity relationship was analysed by molecular modeling. Apigenin presented an unexpected cellular antioxidation behaviour. It had an antioxidant activity at low concentration and a prooxidant activity at high concentration, whereas 2″-O-β-D-xylosylvitexin showed a dose-dependent cellular antioxidant activity. It indicated that C-glycosidation improved the cellular antioxidation performance of apigenin and eliminated the prooxidant effect. The ortho-dihydroxyl at C-3'/C-4' and C-3 hydroxyl in the flavonoid skeleton play important roles in the antioxidation behaviour. The cell proliferation assay revealed a low cytotoxicity of 2″-O-β-D-xylosylvitexin. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Antigenotoxic prenylated flavonoids from stem bark of Erythrina latissima.

    Science.gov (United States)

    Zarev, Yancho; Foubert, Kenn; Lucia de Almeida, Vera; Anthonissen, Roel; Elgorashi, Esameldin; Apers, Sandra; Ionkova, Iliana; Verschaeve, Luc; Pieters, Luc

    2017-09-01

    A series of prenylated flavonoids was obtained from antigenotoxic extracts and fractions of stem bark of Erythrina latissima E. Mey (Leguminosae). In addition to five constituents never reported before, i.e. (2S)-5,7-dihydroxy-2-(4-hydroxy-2-(prop-1-en-2-yl)-2,3-dihydrobenzofuran-6-yl)chroman-4-one (erylatissin D), (2S)-5,7-dihydroxy-2-(4-methoxy-2-(prop-1-en-2-yl)-2,3-dihydrobenzofuran-6-yl)chroman-4-one (erylatissin E), 5,7-dihydroxy-3-(4-methoxy-2-(prop-1-en-2-yl)-2,3-dihydrobenzofuran-6-yl)-4H-chromen-4-one (erylatissin F), (2S)-5,7,8'-trihydroxy-2',2'-dimethyl-[2,6'-bichroman]-4-one (erylatissin G) and (2S)-5,7-dihydroxy-8'-methoxy-2',2'-dimethyl-[2,6'-bichroman]-4-one (dihydroabyssinin I), 18 known flavonoids were identified. Evaluation of the antigenotoxic properties (against genotoxicity induced by aflatoxin B1, metabolically activated) in the Vitotox assay revealed that most flavonoids were active. Sigmoidin A and B showed the highest activity, with an IC 50 value of 18.7 μg/mL, equivalent to that of curcumin (IC 50 18.4 μg/mL), used as a reference antigenotoxic compound. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Flavonoids and Melanins: a common strategy across two kingdoms.

    Science.gov (United States)

    Carletti, Giorgia; Nervo, Giuseppe; Cattivelli, Luigi

    2014-01-01

    Ultraviolet (UV) radiations alter a number of metabolic functions in vivant. They produce damages to lipids, nucleic acids and proteins, generating reactive oxygen species such as singlet oxygen (O2), hydroxyl radical (HO) and superoxide anion (O2 (-)). Plants and animals, after their water emersion, have developed biochemical mechanisms to protect themselves from that environmental threat through a common strategy. Melanins in animals and flavonoids in plants are antioxidant pigments acting as free radical scavenging mechanisms. Both are phenol compounds constitutively synthesized and enhanced after exposure to UV rays, often conferring a red-brown-dark tissue pigmentation. Noteworthy, beside anti-oxidant scavenging activity, melanins and flavonoids have acquired secondary functions that, both in plants and animals, concern reproductions and fitness. Plants highly pigmented are more resistant to biotic and abiotic stresses. Darker wild vertebrates are generally more aggressive, sexually active and resistant to stress than lighter individuals. Flavonoids have been associated with signal attraction between flowers and insects and with plant-plant interaction. Melanin pigmentation has been proposed as trait in bird communication, acting as honest signals of quality. This review shows how the molecular mechanisms leading to tissue pigmentation have many functional analogies between plants and animals and how their origin lies in simpler organisms such as Cyanobacteria. Comparative studies between plant and animal kingdoms can reveal new insight of the antioxidant strategies in vivant.

  2. Comparative mutagenesis of plant flavonoids in microbial systems

    Energy Technology Data Exchange (ETDEWEB)

    Hardigree, A.A.; Epler, J.L.

    1978-01-01

    The plant flavonoids quercetin (3,5,7,3',4'-pentahydroxyflavone), morin (3,5,7,2'4'-pentahydroxyflavone), kaempferol (3,5,7,4'tetrahydroxyflavone), chrysin (5,7-dihydroxyflavone), fisetin (3,7,3',4'-tetrahydroxyflavone), myricetin (3,5,7,3',4',5'-hexahydroxyflavone), myricitrin (myricetin-3-rhamnoside), hesperetin (3',5,7-trihydroxy-4'-methoxyflavanone), quercitrin (quercetin-3-L-rhamnoside), rutin (quercetin-3-rhamnosylglucoside or quercetin-3-rutinoside), and hesperidin (hesperetin-7-rutinoside) have been assayed for mutagenicity in the Salmonella/microsomal activation system. Quercetin, morin, kaempferol, fisetin, myricetin, quercitrin and rutin were mutagenic in the histidine reversion system with the frameshift strain TA98. The flavonols quercetin and myricetin are mutagenic without metabolic activation, although more effective when a rat liver microsomal preparation (S-9) is included; all others require metabolic activation. Flavonoids are common constituents of higher plants, with extensive medical uses. In addition to pure compounds, we have examined crude extracts of tobacco (snuff) and extracts from commonly available nutritional supplements containing rutin. Mutagenic activity can be detected and is correlated with the flavonoid content.

  3. Complexation of Flavonoids with Iron: Structure and Optical Signatures

    Science.gov (United States)

    Ren, Jun; Meng, Sheng; Lekka, Ch. E.; Kaxiras, Efthimios

    2008-03-01

    Flavonoids exhibit antioxidant behavior believed to be related to their metal ion chelation ability. We investigate the complexation mechanism of several flavonoids, quercetin, luteolin, galangin, kaempferol and chrysin with iron, the most abundant type of metal ions in the body, through first- principles electronic structure calculations based on Density Functional Theory (DFT). We find that the most likely chelation site for Fe is the 3-hydroxyl-4-carbonyl group, followed by 4- carbonyl-5-hydroxyl group and the 3'-4' hydroxyl (if present) for all the flavonoid molecules studied. Three quercetin molecules are required to saturate the bonds of a single Fe ion by forming six orthogonal Fe-O bonds, though the binding energy per molecule is highest for complexes consisting of two quercetin molecules and one Fe atom, in agreement with experiment. Optical absorption spectra calculated with time- dependent DFT serve as signatures to identify various complexes. For the iron-quercetin complexes, we find a redshift of the first absorbance peak upon complexation in good agreement with experiment; this behavior is explained by the narrowing of the optical gap of quercetin due to Fe(d)--O(p) orbital hybridization.

  4. Flavonoids and coumarins from Hieracium pilosella L. (Asteraceae

    Directory of Open Access Journals (Sweden)

    Tadeusz Krzaczek

    2011-01-01

    Full Text Available Typical chromatographic methods were successfully applied to isolate nine flavonoid compounds and two coumarin glycosides from the inflorescences and the herb of Hieracium pilosella L. Repeated column chromatography, occasionally paper chromatography and recrystallization made the separation of three flavonoid aglycones and six glycosides - possible. Coumarin glycosides were isolated by preparative thin layer chromatography. Subsequent UV, NMR and MS analyses have led to identification of the following flavonoid derivatives: known for the species - apigenin, luteolin, luteolin 7-O- ß-glucopyranoside, luteolin 4’-O-ß-glucopyranoside, isoetin 7-O-ß- -glucopyranoside, isoetin 4’-O-ß-glucuronide and new for the species – kaempferol 3-methyl ether and apigenin 7-O-ß-glucopyranoside. Third isoetin glycoside contained two different sugar moieties: xylose and glucose, probably attached to the hydroxyl groups at C-4’ or C-4’ and C-2’(or 5’ of an aglycone. Umbelliferone 7-O-ß-glucopyranoside (skimmin and new for the genus Hieracium esculetin 7-O-ß-glucopyranoside (cichoriin were determined by NMR and MS methods.

  5. Seasonal variation of flavonoids in Teucrium polium L. (Lamiaceae

    Directory of Open Access Journals (Sweden)

    Gjoshe Stefkov

    2009-02-01

    Full Text Available Тhe aim of the present study was identification of flavone aglycones and determination of the content of each and the content of total flavonoids as well as investigation of the eventual seasonal variations of flavonoids in Teucrium polium L. (Lamiaceae. The plant samples were collected at six different locations in Republic of Macedonia, during summer in 1999, 2000 and 2003. For determination of seasonal variations, the samples were collected in v. Koleshino, in 2004, each month during the whole season. Six flavone aglycones (luteolin, apigenin, diosmetin, cirsiliol, cirsimaritin and cirsilineol were identified in the hydrolyzed extracts of the over ground part of Teucrium polium by HPLC method. The most abundant flavone was luteolin, followed by apigenin and cirsimaritin. Great seasonal variations were found in the content of each and in the content of total amount of flavonoids. The most abundant flavone during the whole season was luteolin with the highest content in May. The content of total flavonids was the highest in the period from May to July, which could be recommended as the most convenience period in the season for collecting of the plant material from Teucrium polium.

  6. Antiproliferative Activity of Flavonoids from Croton sphaerogynus Baill. (Euphorbiaceae

    Directory of Open Access Journals (Sweden)

    Kátia Pereira dos Santos

    2015-01-01

    Full Text Available Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days, was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1–F5 containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1–F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung, MCF-7 (breast cancer, and U251 (glioma. The MeOH phase showed activity (mean log GI50 0.54 higher than the hexane phase and EtOH extract (mean log GI50 1.13 and 1.19, resp.. F1 exhibited activity against NCI-H460 (nonsmall cell lung (GI50 1.2 μg/mL, which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI50 1.05, while F5 showed weak activity (mean log GI50 1.36. It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes.

  7. Isomerization of butene-1 on rare earth oxides. [Rare earths: La, Nd, Dy

    Energy Technology Data Exchange (ETDEWEB)

    Khodakov, Yu S; Nesterov, V K; Minachev, Kh M [AN SSSR, Moscow. Inst. Organicheskoj Khimii

    1975-09-01

    A study has been made into the isomerization of butene-1 on oxides of rare-earth elements. The dependence of the reaction rate at 20/sup 0/C on the baking temperature of La and Nd oxides have the maximum at 700/sup 0/C. A decrease in the activity of these oxides after bakinq at 800/sup 0/C is observed, as well as during experiments at -30 deq C. In the case of Dy/sub 2/O/sub 3/, the activity at 20/sup 0/C increases gradually with Tsub(bak)=500 to 800/sup 0/C Zeolite 0.57LaNaY exhibits maximum activity at Tsub(bak)=500/sup 0/C Similar data as to the effect of the baking temperature on the catalyst activity were obtained earlier for hydrogenation of ethylene. According to their maximum activity, oxides of rare-earth elements, in the isomerization as well as hydrogenation reactions, can be arranged as follows: La/sub 2/O/sub 3/>Nd/sub 2/O/sub 3/

  8. High-Pressure Limit Rate Rules for α-H Isomerization of Hydroperoxyalkylperoxy Radicals

    KAUST Repository

    Mohamed, Samah Y

    2018-03-09

    Hydroperoxyalkylperoxy (OOQOOH) radical isomerization is an important low-temperature chain branching reaction within the mechanism of hydrocarbon oxidation. This isomerization may proceed via the migration of the α-hydrogen to the hydroperoxide group. In this work, a combination of high level composite methods - CBS-QB3, G3 and G4 - is used to determine the high-pressure-limit rate parameters for the title reaction. Rate rules for H-migration reactions proceeding through 5-, 6-, 7- and 8-membered ring transitions states are determined. Migrations from primary, secondary and tertiary carbon sites to the peroxy group are considered. Chirality is also investigated by considering two diastereomers for reactants and transition states with two chiral centers. This is important since chirality may influence the energy barrier of the reaction as well as the rotational energy barriers of hindered rotors in chemical species and transition states. The effect of chirality and hydrogen bonding interactions in the investigated energies and rate constants is studied. The results show that while the energy difference between two diastereomers ranges from 0.1 - 3.2 kcal, chirality hardly affects the kinetics, except at low temperatures (atmospheric conditions) or when two chiral centers are present in the reactant. Regarding the effects of the peroxy group position and the H-migration ring size, it is found that in most cases, the 1,5 and 1,6 H-migration reactions have similar rates at low temperatures (below ~830K) since the 1,6 H-migration proceeds via a cyclohexane-like transition state similar to that of the 1,5 H-migration.

  9. Interaction of slow neutrons with the second isomeric level Kπ=16+ of the 178Hf isotope

    International Nuclear Information System (INIS)

    Pangault, Laurence

    1999-01-01

    In this work, we study the interaction of low energy neutrons (E≤ 10 eV) with the second isomeric level of 178 Hf (l π =K π =16 + , T 1/2 =31 y) in (n,γ) reactions which proceed through the formation of a compound nucleus. The radiative decay of high K states in 179 Hf is investigated using an isomeric I π =16 + 178 Hf target, 40 ng in weight. The first experiment, performed at the high flux reactor in the Laue Langevin Institute in Grenoble, consisted in γ-ray spectroscopy measurements. For this purpose, an experimental set-up has been built. lt consists of four large Ge detectors shielded against background using a specific F 6 Li collimations ensemble. The second experiments performed at the Fakel (Kurchatov lnstitute, Moscow) and Gelina (IRMM Geel, Belgium) linear accelerators consisted in the investigation of neutron resonances in the 178 Hf m2 (n,γ) reaction using time of flight technique and their γ-decay paths. A high efficiency spectrometer has been built and used for the measurements at bath sites. Two resonances located at 1.82 eV and 0.75 eV have been observed and unambiguously assigned to the (n+ 178 Hf m2 ) compound system. The γ-decay properties of these resonances are very different. Furthermore, the γ-decay path followed by the 0.75 eV resonance is at odd with that expected form statistical model predictions. (author) [fr

  10. Flavonoid glycosides from Erythroxylum pulchrum A. St.-Hil. (Erythroxylaceae); Flavonoides glicosilados de Erythroxylum pulchrum A. St.-Hil. (Erythroxylaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Camila Holanda de; Tavares, Josean Fechine; Oliveira, Steno Lacerda de; Silva, Taina Souza; Costa, Vicente Carlos de Oliveira; Silva, Marcelo Sobral da, E-mail: josean@ltf.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Centro de Ciencias da Saude. Departamento de Ciencias Farmaceuticas; Goncalves, Gregorio Fernandes; Pessoa, Hilzeth de Luna Freire [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Centro de Ciencias da Saude. Dept. de Biologica Molecular; Agra, Maria de Fatima [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Centro de Biotecnologia. Departamento de Biotecnologia

    2014-07-01

    The phytochemical investigation of Erythroxylum pulchrum St. Hil. (Erythroxylaceae) led to the isolation of three known flavonoid glycosides quercetin-3-O-α-L-rhaminoside, ombuin-3-ruthinoside and ombuin-3-ruthinoside-5-glucoside. These flavonoids are being described for the first time in this E. pulchrum. The structures of the compounds were determined by analysis of IR, MS and NMR data, as well as by comparison with literature data. The methanolic extract of leaves from E. pulchrum inhibited the growth of the Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, P. aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, S. aureus ATCC 25925, Streptococcus sanguinis ATCC 15300, S. salivarius ATCC 7073, S. mutans ATCC 25175 and Streptococcus ATCC. S. aureus ATCC 25925 was the most sensitive among the other S. sanguinis while S. salivarius proved the most resistant. (author)

  11. Cardiopulmonary Exercise Testing in Fontan Patients With and Without Isomerism (Heterotaxy) as Compared to Patients With Primary Ciliary Dyskinesia and Subjects With Structurally Normal Hearts

    DEFF Research Database (Denmark)

    Loomba, Rohit S; Danduran, Michael; Nielsen, Kim G

    2017-01-01

    with and without isomerism. We have now compared these finding with those from patients with primary ciliary dyskinesia, as many patients with isomerism have ciliary dyskinesia. We identified patients having the Fontan circulation with and without isomerism who had undergone cardiopulmonary exercise testing......, comparing the findings from healthy individuals undergoing exercise, and a comparable number of individuals with primary ciliary dyskinesia but no congenital heart disease. We were able to include a total of 68 patients in our study, with 17 in each of the four groups. Cardiopulmonary exercise testing...

  12. Cytotoxicity of flavonoid glycosides, flavonoids and phenolic acids from Inula oculus-christi on mammalian cell lines

    Directory of Open Access Journals (Sweden)

    Ralitsa K. Veleva

    2016-12-01

    Full Text Available Herbs of the genus Inula are well known in traditional medicine. Their extracts are used as expectorants, antitussives, bactericides as well as for the treatment of lung inflammation and have shown to possess anti-inflammatory and secretolytic activity. Experimental research findings indicate the anti-tumor effect of certain components of extracts from Inula cappa and Inula britannicа and those from Inula racemosa have antimicrobial and antidiabetic activity. We have directed our efforts on investigating the effects of different extracts from Inula oculus-christi, enriched with certain groups of biologically active substances - flavonoid glycosides (A, phenolic acids (B, flavonoid glycosides and phenolic acids (C, flavonoids and phenolic acids (D. The effect of these extracts on normal (MDCK ІІ and RPE1 and carcinoma cell lines (A549 and HepG2 was evaluated. We have performed cytotoxicity study (crystal violet assay as well as morphological analysis of changes induced by the extracts. Among the tumor cell lines HepG2 show greater sensitivity. Surprisingly extract C has no significant influence on both cancer cell lines.

  13. Extraction and determination of total flavonoids in jujube by alcohol extraction

    Science.gov (United States)

    Ji, Y. B.; Ru, X.; Yu, M.; Wang, S. W.; Lu, L.; Qiao, A. N.; Guo, A. Z.

    2017-12-01

    Jujube is a ripe fruit of Rhamnaceae. Its main active component is flavonoids, so the extraction and determination of total flavonoids in jujube will help to develop and utilize the medicinal value of jujube. In this study, the total flavonoids were extracted from jujube by alcohol extraction method. Through single factor investigation and orthogonal test, it was found that the total flavonoids content in jujube was the highest under the condition of 70°C, material ratio of 1:40, and extraction of 30 min by 70% ethanol. The content of total flavonoids in the extract of jujube was 1.57% at the wavelength of 510 nm by UV and rutin as the standard. The method was evaluated by methodological study, and it was determined that this method could be used as the detection of total flavonoids in jujube extraction.

  14. Study on the high flavonoids mutants of tartarian buckwheat by radiation induced mutation

    International Nuclear Information System (INIS)

    Li Guozhu; Shen Huifang

    2012-01-01

    Three different varieties of tartarian buckwheat seeds (Chuanqiao 1#, Yu-621 and KP9920) were irradiated with various doses (100∼500 Gy) of 60 Co-γ ray and sowed. Ten, eight and six high flavonoid tartary buckwheat mutants were selected from three parent materials respectively. The flavonoid content of three parent materials were 8.33%, 10.18% and 9.80%. The range of flavonoid content of high flavonoids mutants for three parent materials 11.37%∼14.91%, 10.67%∼12.46% and 11.32%∼12.95% respectively. Cluster analysis was also carried out based on the agronomic traits and flavonoid content in the 27 tartary buckwheat materials (24 mutants and 3 parent material) The 27 materials were classified into four clusters by cluster analysis based on the agronomic traits and were classified into 5 groups based on flavonoid content. (authors)

  15. Flavonoids in human urine as biomarkers for intake of fruits and vegetables

    DEFF Research Database (Denmark)

    Nielsen, Salka E.; Freese, R.; Kleemola, P.

    2002-01-01

    Flavonoids are polyphenolic compounds ubiquitously found in human diets. We have studied the association between urinary excretion of flavonoids and the intake of fruits and vegetables to evaluate the usefulness of flavonoids as a biomarker for fruit and vegetable intake. Levels of 12 dietary...... relevant flavonoids were determined by LC-MS in urine samples collected prior to an intervention study, when the subjects were on their habitual diet (n = 94), and after they had participated in an intervention study with diets either high or low in fruits, berries, and vegetables (n = 77). Both flavonoid...... glycosides and aglycones were included in the assay, but only the flavonoid aglycones were detectable. Thus, the flavonols quercetin, kaempferol, isorhamnetin, and tamarixetin, the dihydrochalcone phloretin, and the flavanones naringenin and hesperetin were quantified in the enzymatically hydrolyzed urine...

  16. Interaction of flavonoids, the naturally occurring antioxidants with different media: a UV-visible spectroscopic study.

    Science.gov (United States)

    Naseem, Bushra; Shah, S W H; Hasan, Aurangzeb; Sakhawat Shah, S

    2010-04-01

    Quantitative parameters for interaction of flavonoids-the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, K(c). Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities. Copyright 2010 Elsevier B.V. All rights reserved.

  17. The Creation and Physiological Relevance of Divergent Hydroxylation Patterns in the Flavonoid Pathway

    Directory of Open Access Journals (Sweden)

    Heidi Halbwirth

    2010-02-01

    Full Text Available Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have in common a basic C6-C3-C6 skeleton structure consisting of two aromatic rings (A and B and a heterocyclic ring (C containing one oxygen atom, whereas chalcones, as the intermediates in the formation of flavonoids, have not yet established the heterocyclic C-ring. Flavonoids are grouped into eight different classes, according to the oxidative status of the C-ring. The large number of divergent chalcones and flavonoid structures is from the extensive modification of the basic molecules. The hydroxylation pattern influences physiological properties such as light absorption and antioxidative activity, which is the base for many beneficial health effects of flavonoids. In some cases antiinfective properties are also effected.

  18. HL-60 differentiating activity and flavonoid content of the readily extractable fraction prepared from citrus juices.

    Science.gov (United States)

    Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

    1999-01-01

    Citrus plants are rich sources of various bioactive flavonoids. To eliminate masking effects caused by hesperidin, naringin, and neoeriocitrin, the abundant flavonoid glycosides which make up 90% of the conventionally prepared sample, the readily extractable fraction from Citrus juice was prepared by adsorbing on HP-20 resin and eluting with EtOH and acetone from the resin and was subjected to HL-60 differentiation assay and quantitative analysis of major flavonoids. Screening of 34 Citrus juices indicated that King (C. nobilis) had a potent activity for inducing differentiation of HL-60, and the active principles were isolated and identified as four polymethoxylated flavonoids, namely, nobiletin, 3,3',4',5,6,7, 8-heptamethoxyflavone, natsudaidain, and tangeretin. HPLC analysis of the readily extractable fraction also indicated that King contained high amounts of these polymethoxylated flavonoids among the Citrus juices examined. Principal component and cluster analyses of the readily extractable flavonoids indicated peculiarities of King and Bergamot.

  19. Study on the high flavonoids mutants of tartarian buckwheat by radiation induced

    International Nuclear Information System (INIS)

    Li Guozhu; Shen Huifang

    2011-01-01

    Three different varieties of tartarian buckwheat seeds (Chuanqiao 1 # , Yu-621 and KP9920) were irradiated with various doses (100∼500 Gy) of 60 Co-γ ray and sowed. Ten, eight and six high flavonoid tartary buckwheat mutants were selected from three parent materials respectively. The flavonoid content of three parent materials were 8.33%, 10.18% and 9.80%. The range of flavonoid content of high flavonoids mutants for three parent materials 11.37%∼14.91%, 10.67%∼12.46% and 11.32%∼12.95% respectively. Cluster analysis was also carried out based on the agronomic traits and flavonoid content in the 27 tartary buckwheat materials (24 mutants and 3 parent material) The 27 materials were classified into four clusters by cluster analysis based on the agronomic traits and were classified into 5 groups based on flavonoid content. (authors)

  20. Enhancement of Solubility and Antioxidant Activity of Some Flavonoids Based on the Inclusion Complexation with Sulfobutylether β-Cyclodextrin

    International Nuclear Information System (INIS)

    Kwon, Yong Eun; Kim, Hyun Myung; Jung, Seun Ho; Park, Se Yeon

    2010-01-01

    β-CD and SBE-β-CD functioned as a solubilizing agent against three flavonoids. SBE-β-CD is more efficient than native β-CD in solubility enhancement of tested flavonoids. All three tested flavonoids have antioxidant ability. Flavonoid-CD complex positively affected the antioxidant activity comparing with free flavonoids. Throughout this research, SBE-β-CD showed better complexation capacity for the solubility enhancement and bioavailability of tested flavonoids comparing with native β-CD. Flavonoids are polyphenolic photochemicals generally found in plants, foods, and beverages. They contribute to plant colors in fruit, leaves providing a wide spectrum of color from red to blue in flowers. Flavonoids have many good physiological activities such as the antioxidant, antitumor, and antibacterial activities which have been a focus of the attention of many researchers. There are four subgroups of flavonoids, flavone, flavonol, flavanone, and isoflavone, according to their chemical structure

  1. Quantitative Structure – Antioxidant Activity Relationships of Flavonoid Compounds

    Directory of Open Access Journals (Sweden)

    Károly Héberger

    2004-12-01

    Full Text Available A quantitative structure – antioxidant activity relationship (QSAR study of 36 flavonoids was performed using the partial least squares projection of latent structures (PLS method. The chemical structures of the flavonoids have been characterized by constitutional descriptors, two-dimensional topological and connectivity indices. Our PLS model gave a proper description and a suitable prediction of the antioxidant activities of a diverse set of flavonoids having clustering tendency.

  2. Quantitative modeling of flavonoid glycosides isolated from Paliurus spina-christi Mill.

    OpenAIRE

    Medić-Šarić, Marica; Maleš, Željan; Šarić, Slavko; Brantner, Adelheid

    1996-01-01

    Several QSPR models for predicting the properties of flavonoid glycosides isolated from Paliurus spina-christi Mill, and of some related flavonoids were described and evaluated. Log P values for all of them were calculated according to the method of Rekker. All investigated flavonoids showed expressive hydrophobicity. Significant correlation between the partition coefficient, log P, and van der Waals volume, Vw (calculated according to the method described by Moriguchi et al.) was obtained. T...

  3. Compartmental and noncompartmental modeling of ¹³C-lycopene absorption, isomerization, and distribution kinetics in healthy adults.

    Science.gov (United States)

    Moran, Nancy E; Cichon, Morgan J; Riedl, Kenneth M; Grainger, Elizabeth M; Schwartz, Steven J; Novotny, Janet A; Erdman, John W; Clinton, Steven K

    2015-12-01

    Lycopene, which is a red carotenoid in tomatoes, has been hypothesized to mediate disease-preventive effects associated with tomato consumption. Lycopene is consumed primarily as the all-trans geometric isomer in foods, whereas human plasma and tissues show greater proportions of cis isomers. With the use of compartmental modeling and stable isotope technology, we determined whether endogenous all-trans-to-cis-lycopene isomerization or isomeric-bioavailability differences underlie the greater proportion of lycopene cis isomers in human tissues than in tomato foods. Healthy men (n = 4) and women (n = 4) consumed (13)C-lycopene (10.2 mg; 82% all-trans and 18% cis), and plasma was collected over 28 d. Unlabeled and (13)C-labeled total lycopene and lycopene-isomer plasma concentrations, which were measured with the use of high-performance liquid chromatography-mass spectrometry, were fit to a 7-compartment model. Subjects absorbed a mean ± SEM of 23% ± 6% of the lycopene. The proportion of plasma cis-(13)C-lycopene isomers increased over time, and all-trans had a shorter half-life than that of cis isomers (5.3 ± 0.3 and 8.8 ± 0.6 d, respectively; P lycopene bioavailability and endogenous trans-to-cis-lycopene isomerization was predictive of plasma (13)C and unlabeled cis- and all-trans-lycopene concentrations. Although the bioavailability of cis (24.5% ± 6%) and all-trans (23.2% ± 8%) isomers did not differ, endogenous isomerization (0.97 ± 0.25 μmol/d in the fast-turnover tissue lycopene pool) drove tissue and plasma isomeric profiles. (13)C-Lycopene combined with physiologic compartmental modeling provides a strategy for following complex in vivo metabolic processes in humans and reveals that postabsorptive trans-to-cis-lycopene isomerization, and not the differential bioavailability of isomers, drives tissue and plasma enrichment of cis-lycopene. This trial was registered at clinicaltrials.gov as NCT01692340. © 2015 American Society for Nutrition.

  4. Compartmental and noncompartmental modeling of 13C-lycopene absorption, isomerization, and distribution kinetics in healthy adults123

    Science.gov (United States)

    Moran, Nancy E; Cichon, Morgan J; Riedl, Kenneth M; Grainger, Elizabeth M; Schwartz, Steven J; Novotny, Janet A; Erdman, John W; Clinton, Steven K

    2015-01-01

    Background: Lycopene, which is a red carotenoid in tomatoes, has been hypothesized to mediate disease-preventive effects associated with tomato consumption. Lycopene is consumed primarily as the all-trans geometric isomer in foods, whereas human plasma and tissues show greater proportions of cis isomers. Objective: With the use of compartmental modeling and stable isotope technology, we determined whether endogenous all-trans-to-cis-lycopene isomerization or isomeric-bioavailability differences underlie the greater proportion of lycopene cis isomers in human tissues than in tomato foods. Design: Healthy men (n = 4) and women (n = 4) consumed 13C-lycopene (10.2 mg; 82% all-trans and 18% cis), and plasma was collected over 28 d. Unlabeled and 13C-labeled total lycopene and lycopene-isomer plasma concentrations, which were measured with the use of high-performance liquid chromatography–mass spectrometry, were fit to a 7-compartment model. Results: Subjects absorbed a mean ± SEM of 23% ± 6% of the lycopene. The proportion of plasma cis-13C-lycopene isomers increased over time, and all-trans had a shorter half-life than that of cis isomers (5.3 ± 0.3 and 8.8 ± 0.6 d, respectively; P lycopene bioavailability and endogenous trans-to-cis-lycopene isomerization was predictive of plasma 13C and unlabeled cis- and all-trans-lycopene concentrations. Although the bioavailability of cis (24.5% ± 6%) and all-trans (23.2% ± 8%) isomers did not differ, endogenous isomerization (0.97 ± 0.25 μmol/d in the fast-turnover tissue lycopene pool) drove tissue and plasma isomeric profiles. Conclusion: 13C-Lycopene combined with physiologic compartmental modeling provides a strategy for following complex in vivo metabolic processes in humans and reveals that postabsorptive trans-to-cis-lycopene isomerization, and not the differential bioavailability of isomers, drives tissue and plasma enrichment of cis-lycopene. This trial was registered at clinicaltrials.gov as NCT01692340. PMID

  5. Qualitative and quantitative analysis of flavonoids of the strawberry tree - Arbutus unedo L. (Ericaceae).

    Science.gov (United States)

    Males, Zeljan; Plazibat, Misko; Vundać, Vjera Bilusić; Zuntar, Irena

    2006-06-01

    The leaves and fruits of strawberry tree - Arbutus unedo L., collected from two separate geographic locations in Croatia were investigated to determine their flavonoid composition and content. Quercitrin, isoquercitrin, hyperoside and rutin were identified in all leaf samples by means of thin-layer chromatography; the fruits contained only isoquercitrin. Chlorogenic acid was present in some leaf samples. The content of flavonoids depended on the plant organ investigated, date of collection and the locality. Spectrophotometric determination of the flavonoids indicated that the leaves are richer in flavonoids (0.52-2.00%) than fruits (0.10-0.29%).

  6. Optimization of the extraction of flavonoids from grape leaves by response surface methodology

    International Nuclear Information System (INIS)

    Brad, K.; Liu, W.

    2013-01-01

    The extraction of flavonoids from grape leaves was optimized to maximize flavonoids yield in this study. A central composite design of response surface methodology involving extracting time, power, liquid-solid ratio, and concentration was used, and second-order model for Y was employed to generate the response surfaces. The optimum condition for flavonoids yield was determined as follows: extracting time 24.95 min, power 72.05, ethanol concentration 63.35%, liquid-solid ratio 10.04. Under the optimum condition, the flavonoids yield was 76.84 %. (author)

  7. Antioxidant Activities and Chemical Constituents of Flavonoids from the Flower of Paeonia ostii.

    Science.gov (United States)

    Zhang, Huifang; Li, Xiaofang; Wu, Ke; Wang, Mengke; Liu, Pu; Wang, Xinsheng; Deng, Ruixue

    2016-12-23

    Paeonia ostii is a traditional medicinal plant popularly used in China. This study intended to evaluate the antioxidant properties and the chemical components of the flavonoid-rich extracts from the flowers of P. ostii . The results showed that the flavonoid-rich extracts from the flowers of P. ostii had strong scavenging capacities on 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS), hydroxyls, superoxide anions, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals in a dose-dependent manner. Five flavonoids, dihydrokaempferol ( 1 ), apigenin-7- O -β-d-glucoside ( 2 ), apigenin-7- O -β-d-neohesperidoside ( 3 ), kaempferol-7- O -β-d-glucopyranoside ( 4 ), and kaempferol-3- O -β-d-glucopyranosyl-7- O -β-d-glucopyranoside ( 5 ), were isolated from the flavonoid-rich extracts of the flowers of P. ostii . High-performance liquid chromatography (HPLC) analysis revealed that compounds 3 and 4 were abundant in the P. ostii flower and in flavonoid-rich extracts. The main components of the flower of P. ostii are flavonoids. The high antioxidant activity of the flavonoid-rich extracts may be attributed to the high content of flavonoids. The five isolated flavonoids were the primary antioxidant ingredients, and may play important roles in the strong antioxidant activities of this flower. Based on the obtained results, the flower of P. ostii could be a potential source of natural antioxidants in food and pharmaceutical applications.

  8. Preparative Separation and Purification of the Total Flavonoids in Scorzonera austriaca with Macroporous Resins.

    Science.gov (United States)

    Xie, Yang; Guo, Qiu-Shi; Wang, Guang-Shu

    2016-06-13

    The use of macroporous resins for the separation and purification of total flavonoids to obtain high-purity total flavonoids from Scorzonera austriaca was studied. The optimal conditions for separation and purification of total flavonoids in S. austriaca with macroporous resins were as follows: D4020 resin columns were loaded with crude flavonoid extract solution, and after reaching adsorptive saturation, the columns were eluted successively with 5 bed volumes (BV) of water, 5 BV of 5% (v/v) aqueous ethanol and 5 BV of 30% (v/v) aqueous ethanol at an elute flow rate of 2 BV·h(-1). Total flavonoids were obtained from the 30% aqueous ethanol eluate by vacuum distillation recovery. The content of flavonoid compounds in the total flavonoids was 93.5%, which represents an improvement by about 150%. In addition, five flavonoid compounds in the product were identified as 2″-O-β-d-xylopyranosyl isoorientin, 6-C-α-l-arabipyranosyl orientin, orientin, isoorientin and vitexin by LC-ESI-MS analysis and internal standard methods. The results in this study could represent a method for the large-scale production of total flavonoids from S. austriaca.

  9. The role of metabolism (and the microbiome) in defining the clinical efficacy of dietary flavonoids.

    Science.gov (United States)

    Cassidy, Aedín; Minihane, Anne-Marie

    2017-01-01

    At a population level, there is growing evidence of the beneficial effects of dietary flavonoids on health. However, there is extensive heterogeneity in the response to increased intake, which is likely mediated via wide interindividual variability in flavonoid absorption and metabolism. Flavonoids are extensively metabolized by phase I and phase II metabolism (which occur predominantly in the gastrointestinal tract and liver) and colonic microbial metabolism. A number of factors, including age, sex, and genotype, may affect these metabolic processes. In addition, food composition and flavonoid source are likely to affect bioavailability, and emerging data suggest a critical role for the microbiome. This review will focus on the current knowledge for the main subclasses of flavonoids, including anthocyanins, flavonols, flavan-3-ols, and flavanones, for which there is growing evidence from prospective studies of beneficial effects on health. The identification of key factors that govern metabolism and an understanding of how the differential capacity to metabolize these bioactive compounds affect health outcomes will help establish how to optimize intakes of flavonoids for health benefits and in specific subgroups. We identify research areas that need to be addressed to further understand important determinants of flavonoid bioavailability and metabolism and to advance the knowledge base that is required to move toward the development of dietary guidelines and recommendations for flavonoids and flavonoid-rich foods.

  10. The flavonoid pathway in tomato seedlings: transcript abundance and the modeling of metabolite dynamics.

    Directory of Open Access Journals (Sweden)

    Marian Groenenboom

    Full Text Available Flavonoids are secondary metabolites present in all terrestrial plants. The flavonoid pathway has been extensively studied, and many of the involved genes and metabolites have been described in the literature. Despite this extensive knowledge, the functioning of the pathway in vivo is still poorly understood. Here, we study the flavonoid pathway using both experiments and mathematical models. We measured flavonoid metabolite dynamics in two tissues, hypocotyls and cotyledons, during tomato seedling development. Interestingly, the same backbone of interactions leads to very different accumulation patterns in the different tissues. Initially, we developed a mathematical model with constant enzyme concentrations that described the metabolic networks separately in both tissues. This model was unable to fit the measured flavonoid dynamics in the hypocotyls, even if we allowed unrealistic parameter values. This suggested us to investigate the effect of transcript abundance on flavonoid accumulation. We found that the expression of candidate flavonoid genes varies considerably with time. Variation in transcript abundance results in enzymatic variation, which could have a large effect on metabolite accumulation. Candidate transcript abundance was included in the mathematical model as representative for enzyme concentration. We fitted the resulting model to the flavonoid dynamics in the cotyledons, and tested it by applying it to the data from hypocotyls. When transcript abundance is included, we are indeed able to explain flavonoid dynamics in both tissues. Importantly, this is possible under the biologically relevant restriction that the enzymatic properties estimated by the model are conserved between the tissues.

  11. Flavonoids are systemically induced by UV-B in Zea mays

    International Nuclear Information System (INIS)

    Tossi, V.E.; Lamattina, L.; Cassia, R.

    2009-01-01

    Flavonoid concentration is increased by UV-B irradiation, but it is unknown if this is a local or systemic response. Nitric oxide (NO) is a diffusible molecule involved in the UV-B response. NO regulates the expression of chalcone synthase (CHS), a key enzyme in the synthesis of flavonoids. The aim of this work was to determine if maize flavonoids are local or systemically induced by UV-B, and what is the participation of NO in this response. We have used maize seedlings where the second leaf was sprayed with H 2 O or cPTIO (a NO scavenger), and then completely covered (C), partially covered (P) or uncovered (U) before to be UV-B irradiated. The results show a 60% increase in the NO concentration of U, 42% in P and 35% in C respectively. Flavonoid concentration increased 90% in C, 70% in P and 40% in U. Flavonoid concentration was reduced when leaves were pretreated with cPTIO before the UV-B irradiation. RT-PCR shows that CHS was up-regulated by UV-B in U, P and C, but downregulated with cPTIO. We have analyzed the subcellular localization of flavonoid and NO in UV-B irradiated plants. Flavonoid localization was coincident with the NO presence in the irradiated surface of the leaves and flavonoids were detected in vesicles. These results indicate that flavonoids are systemically induced by UV-B in a NO-related mechanism. (authors)

  12. Effect of room temperature ionic liquid structure on the enzymatic acylation of flavonoids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2010-01-01

    Enzymatic acylation reactions of flavonoids (rutin, esculin) with long chain fatty acids (palmitic, oleic acids) were carried out in 14 different ionic liquid media containing a range of cation and anion structures. Classification of RTILs according to flavonoid solubility (using COSMO...... must be struck that maximized flavonoid solubility with minimum negative impact on lipase activity. The process also benefitted from an increased reaction temperature which may have helped to reduced mass transfer limitations. Keywords: Room temperature ionic liquids (RTILs); Biosynthesis; Acylation......; Flavonoids; Lipase; Long chain fatty acids...

  13. Functional Characterization of a Flavonoid Glycosyltransferase in Sweet Orange (Citrus sinensis).

    Science.gov (United States)

    Liu, Xiaogang; Lin, Cailing; Ma, Xiaodi; Tan, Yan; Wang, Jiuzhao; Zeng, Ming

    2018-01-01

    Fruits of sweet orange ( Citrus sinensis ), a popular commercial Citrus species, contain high concentrations of flavonoids beneficial to human health. These fruits predominantly accumulate O -glycosylated flavonoids, in which the disaccharides [neohesperidose (rhamnosyl-α-1,2-glucose) or rutinose (rhamnosyl-α-1,6-glucose)] are linked to the flavonoid aglycones through the 3- or 7-hydroxyl sites. The biotransformation of the flavonoid aglycones into O -rutinosides or O -neohesperidosides in the Citrus plants usually consists of two glycosylation reactions involving a series of uridine diphosphate-sugar dependent glycosyltransferases (UGTs). Although several genes encoding flavonoid UGTs have been functionally characterized in the Citrus plants, full elucidation of the flavonoid glycosylation process remains elusive. Based on the available genomic and transcriptome data, we isolated a UGT with a high expression level in the sweet orange fruits that possibly encodes a flavonoid glucosyltransferase and/or rhamnosyltransferase. Biochemical analyses revealed that a broad range of flavonoid substrates could be glucosylated at their 3- and/or 7-hydrogen sites by the recombinant enzyme, including hesperetin, naringenin, diosmetin, quercetin, and kaempferol. Furthermore, overexpression of the gene could significantly increase the accumulations of quercetin 7- O -rhamnoside, quercetin 7- O -glucoside, and kaempferol 7- O -glucoside, implying that the enzyme has flavonoid 7- O -glucosyltransferase and 7- O -rhamnosyltransferase activities in vivo .

  14. Optimization of conditions for supercritical fluid extraction of flavonoids from hops (Humulus lupulus L.)*

    Science.gov (United States)

    He, Guo-qing; Xiong, Hao-ping; Chen, Qi-he; Ruan, Hui; Wang, Zhao-yue; Traoré, Lonseny

    2005-01-01

    Waste hops are good sources of flavonoids. Extraction of flavonoids from waste hops (SC-CO2 extracted hops) using supercritical fluids technology was investigated. Various temperatures, pressures and concentrations of ethanol (modifier) and the ratio (w/w) of solvent to material were tested in this study. The results of single factor and orthogonal experiments showed that at 50 °C, 25 MPa, the ratio of solvent to material (50%), ethanol concentration (80%) resulted in maximum extraction yield flavonoids (7.8 mg/g). HPLC-MS analysis of the extracts indicated that flavonoids obtained were xanthohumol, the principal prenylflavonoid in hops. PMID:16187413

  15. Is HO3 minimum cis or trans? An analytic full-dimensional ab initio isomerization path.

    Science.gov (United States)

    Varandas, A J C

    2011-05-28

    The minimum energy path for isomerization of HO(3) has been explored in detail using accurate high-level ab initio methods and techniques for extrapolation to the complete basis set limit. In agreement with other reports, the best estimates from both valence-only and all-electron single-reference methods here utilized predict the minimum of the cis-HO(3) isomer to be deeper than the trans-HO(3) one. They also show that the energy varies by less than 1 kcal mol(-1) or so over the full isomerization path. A similar result is found from valence-only multireference configuration interaction calculations with the size-extensive Davidson correction and a correlation consistent triple-zeta basis, which predict the energy difference between the two isomers to be of only Δ = -0.1 kcal mol(-1). However, single-point multireference calculations carried out at the optimum triple-zeta geometry with basis sets of the correlation consistent family but cardinal numbers up to X = 6 lead upon a dual-level extrapolation to the complete basis set limit of Δ = (0.12 ± 0.05) kcal mol(-1). In turn, extrapolations with the all-electron single-reference coupled-cluster method including the perturbative triples correction yield values of Δ = -0.19 and -0.03 kcal mol(-1) when done from triple-quadruple and quadruple-quintuple zeta pairs with two basis sets of increasing quality, namely cc-cpVXZ and aug-cc-pVXZ. Yet, if added a value of 0.25 kcal mol(-1) that accounts for the effect of triple and perturbative quadruple excitations with the VTZ basis set, one obtains a coupled cluster estimate of Δ = (0.14 ± 0.08) kcal mol(-1). It is then shown for the first time from systematic ab initio calculations that the trans-HO(3) isomer is more stable than the cis one, in agreement with the available experimental evidence. Inclusion of the best reported zero-point energy difference (0.382 kcal mol(-1)) from multireference configuration interaction calculations enhances further the relative

  16. Production cross sections and isomeric ratios for sup(110m)In/sup(110g)In formed in Cd (d,xn) reactions

    International Nuclear Information System (INIS)

    Herreros Usher, Oscar; Maceiras de Jefimowicz, Elena; De la Vega Vedoya, Mario; Jorge Nassiff, Sonia

    1980-01-01

    Excitation functions and isomeric cross sections ratios have been measured for the 110 Cd (d,2n) and 111 Cd (d,3n) reactions in which the isomeric pair sup(110m)In/sup(110g)In is produced. Activation method was employed and the irradiations were performed at the synchrocyclotron of the Comision Nacional de Energia Atomica, Argentina, with an incident energy of 27.MeV. (author) [es

  17. Thermal solid-state Z/E isomerization of 2-alkylidene-4-oxothiazolidines: effects of non-covalent interactions

    Directory of Open Access Journals (Sweden)

    ZDRAVKO DŽAMBASKI

    2011-03-01

    Full Text Available Configurational isomerization of stereo-defined 5-substituted and unsubstituted 2-alkylidene-4-oxothiazolidines (1 in the solid state, giving the Z/E mixtures in various ratios, was investigated by 1H-NMR spectroscopy, X-ray powder crystallography and differential scanning calorimetry (DSC. The Z/E composition can be rationalized in terms of non-covalent interactions, involving intermolecular and intramolecular hydrogen bonding and directional non-bonded 1,5-type S×××O interactions. X-Ray powder crystallography, using selected crystalline (Z-4-oxothiazolidine substrates, revealed transformation to the amorphous state during the irreversible Z®E process. A correlation between previous results on the Z/E isomerization in solution and now in the solid state was established.

  18. Thermally and vibrationally induced conformational isomerizations, infrared spectra, and photochemistry of gallic acid in low-temperature matrices

    Science.gov (United States)

    Justino, Licínia L. G.; Reva, Igor; Fausto, Rui

    2016-07-01

    Near-infrared (near-IR) narrowband selective vibrational excitation and annealing of gallic acid (3,4,5-trihydroxybenzoic acid) isolated in cryogenic matrices were used to induce interconversions between its most stable conformers. The isomerizations were probed by infrared spectroscopy. An extensive set of quantum chemical calculations, carried out at the DFT(B3LYP)/6-311++G(d,p) level of approximation, was used to undertake a detailed analysis of the ground state potential energy surface of the molecule. This investigation of the molecule conformational space allowed extracting mechanistic insights into the observed annealing- or near-IR-induced isomerization processes. The infrared spectra of the two most stable conformers of gallic acid in N2, Xe, and Ar matrices were fully assigned. Finally, the UV-induced photochemistry of the matrix isolated compound was investigated.

  19. Thermally and vibrationally induced conformational isomerizations, infrared spectra, and photochemistry of gallic acid in low-temperature matrices

    International Nuclear Information System (INIS)

    Justino, Licínia L. G.; Reva, Igor; Fausto, Rui

    2016-01-01

    Near-infrared (near-IR) narrowband selective vibrational excitation and annealing of gallic acid (3,4,5-trihydroxybenzoic acid) isolated in cryogenic matrices were used to induce interconversions between its most stable conformers. The isomerizations were probed by infrared spectroscopy. An extensive set of quantum chemical calculations, carried out at the DFT(B3LYP)/6-311++G(d,p) level of approximation, was used to undertake a detailed analysis of the ground state potential energy surface of the molecule. This investigation of the molecule conformational space allowed extracting mechanistic insights into the observed annealing- or near-IR-induced isomerization processes. The infrared spectra of the two most stable conformers of gallic acid in N 2 , Xe, and Ar matrices were fully assigned. Finally, the UV-induced photochemistry of the matrix isolated compound was investigated.

  20. Investigating the large deformation of the 5 /2+ isomeric state in 73Zn: An indicator for triaxiality

    Science.gov (United States)

    Yang, X. F.; Tsunoda, Y.; Babcock, C.; Billowes, J.; Bissell, M. L.; Blaum, K.; Cheal, B.; Flanagan, K. T.; Garcia Ruiz, R. F.; Gins, W.; Gorges, C.; Grob, L. K.; Heylen, H.; Kaufmann, S.; Kowalska, M.; Krämer, J.; Malbrunot-Ettenauer, S.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Otsuka, T.; Papuga, J.; Sánchez, R.; Wraith, C.; Xie, L.; Yordanov, D. T.

    2018-04-01

    Recently reported nuclear spins and moments of neutron-rich Zn isotopes measured at ISOLDE-CERN [C. Wraith et al., Phys. Lett. B 771, 385 (2017), 10.1016/j.physletb.2017.05.085] show an uncommon behavior of the isomeric state in 73Zn. Additional details relating to the measurement and analysis of the Znm73 hyperfine structure are addressed here to further support its spin-parity assignment 5 /2+ and to estimate its half-life. A systematic investigation of this 5 /2+ isomer indicates that significant collectivity appears due to proton/neutron E 2 excitations across the proton Z = 28 and neutron N = 50 shell gaps. This is confirmed by the good agreement of the observed quadrupole moments with large scale Monte Carlo shell model calculations. In addition, potential energy surface calculations in combination with T plots reveal a triaxial shape for this isomeric state.