253 research outputs found

    ENHANCING PRODUCTION THROUGH OPTIMISATION OF DPPH AND RADICAL SCAVENGING ACTIVITY OF GRAPE SEED EXTRACTS

    Get PDF
    Polyphenols are important for their pharmacological activity and positive contribution to cellular processes within the body. They have the capacity to protect against oxidation of High Density Lipids (HDL) and, thus help the body to retain HDL, while removing the problematic Low Density Lipids (LDL). Polyphenols also possess anti-ulcer, anti-carcinogenic and anti-mutagenic activities. The objective of this study was to evaluate the effect of temperature and grain size of grape seed on the efficiency of extraction of polyphenols from grape seed, using the compressed hot water and solvent extraction techniques. Polyphenols were extracted from milled (<0.5 mm) and whole grape seed, using compressed hot water (high temperature and high pressure) and solvents (Acetone, Methanol and Ethanol). The total polyphenol content and DPPH radical scavenging activity of the extracts were determined using spectrometer and the active compounds identified using HPLC. Total polyphenol content increased with extraction temperature, but decreased at 200 \ub0C. The difference in polyphenol extracts from the milled and whole seed decreased with increase in temperature, but was more evident at 135 \ub0C. The 2 hour extracts showed relatively higher values than those for 1 hour, with the lowest difference occurring at 165 \ub0C and the highest at 180 \ub0C. Solvent extracts from whole seeds were very low compared with the milled seeds, with acetone showing the highest value of 105 mg g-1 dry matter for polyphenol content and 110 mg g-1 of dry matter for DPPH radical scavenging activity. Methanol had the lowest value (78 mg g-1 dry matter) for polyphenol extracts and 80 mg g-1 for the DPPH radical scavenging activity. The main extract compounds were gallic acid, catechin and epicatechin.Les polyph\ue9nols sont importants eu \ue9gard \ue0 leur activit\ue9 pharmacologique et leur contribution positive aux processus cellulaires dans le corps. Ils sont dou\ue9s d\u2019une capacit\ue9 protective contre l\u2019oxydation des Lipides \ue0 Densit\ue9 Elev\ue9e (HDL) et, ainsi aident le corps \ue0 maintenir le HDL, tout en \ue9liminant les probl\ue9matiques Lipides \ue0 Basse Densit\ue9. Les polyph\ue9nols poss\ue8dent aussi des activit\ue9s anti-ulc\ue8res, anticarcinog\ue8nes et antimutag\ue8nes. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer les effets de la temp\ue9rature et taille des grains de raisin sur l\u2019efficacit\ue9 de l\u2019extraction des polyph\ue9nols des grains de raisin, utilisant une eau chaude compress\ue9e et des techniques d\u2019extraction au solvant. Les polyphenols \ue9taient extraits des grains entiers de raisin et des grains moulus (<0.5 mm) \ue0 l\u2019aide d\u2019une eau chaude compress\ue9e (temp\ue9rature \ue9lev\ue9e et haute pression) et des solvants (Ac\ue9tone, M\ue9thanol et Ethanol). La concentration totale des polyph\ue9nols et l\u2019activit\ue9 d\u2019absoption du radical DPPH des extraits \ue9taient d\ue9termin\ue9s \ue0 l\u2019aide du spectrophotom\ue8tre et les compos\ue9s actifs identifi\ue9s par HPLC. La concentration totale des polyph\ue9nols a augment\ue9 avec la temp\ue9rature d\u2019extraction, mais a diminu\ue9 \ue0 200 \ub0C. La diff\ue9rence dans les extraits de polyph\ue9nol des grains moulus et entiers a diminu\ue9 avec l\u2019augmentation de la temperature, mais \ue9tait plus \ue9vidente \ue0 135 \ub0C. Les extraits de deux heures ont montr\ue9 des valeurs relativement plus \ue9lev\ue9es que ceux d\u2019une heure, avec les diff\ue9rences les plus faibles apparaissant \ue0 165 \ub0C et les plus \ue9lev\ue9es \ue0 180 \ub0C. Les extraits de graines enti\ue8res aux solvants \ue9taient de faible quantit\ue9 en comparaison avec ceux des grains moulus, les valeurs les plus \ue9lev\ue9es \ue9tant de 105 mg g-1 de mati\ue8re s\ue8che de polyph\ue9nol et 110 mg g-1 de mati\ue8re s\ue8che d\u2019absorption du radical DPPH obtenues en utilisant l\u2019ac\ue9tone comme solvant. Les extraits obtenus au m\ue9thanol comme solvant \ue9taient encore en plus faible quantit\ue9 avec 78 mg-1 de la mati\ue8re s\ue8che pour les extraits du polyph\ue9nol et 80 mg g-1 pour l\u2019activit\ue9 d\u2019absorption du DPPH. Les principaux compos\ue9s de ces extraits \ue9taient des acides galliques, des cat\ue9chines et des epicat\ue9chines

    Observation of Large CP Violation in the Neutral B Meson System

    Full text link
    We present a measurement of the Standard Model CP violation parameter sin 2phi_1 based on a 29.1 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. One neutral B meson is fully reconstructed as a J/psi Ks, psi(2S) Ks, chi_c1 Ks, eta_c Ks, J/psi K_L or J/psi K^{*0} decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin 2phi_1 = 0.99 +- 0.14(stat) +- 0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.Comment: 4 figures, to appear in Phys. Rev. Letter

    Measurement of B0d - B0d-bar mixing rate from the time evolution of dilepton events at the Upsilon(4S)

    Full text link
    We report a determination of the B0d - B0d-bar mixing parameter Delta-m_d based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 /fb data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Delta-m_d as a free parameter. Using both muons and electrons, we obtain Delta-m_d = 0.463 +- 0.008(stat.) +- 0.016(sys.) ps^{-1} This is the first determination of Delta-m_d from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.Comment: 12 pages, 2 figure

    Study of CP-Violating Asymmetries in B0 -> pi+pi- Decays

    Full text link
    We present a measurement of CP-violating asymmetries in B0 -> pi+pi- decays based on a 41.8 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We fully reconstruct one neutral B meson as a B0 -> pi+pi- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we obtain the CP-violating asymmetry parameters Spipi = -1.21 +0.38/-0.27(stat) +0.16/-0.13(syst) and Apipi = +0.94 +0.25/-0.31(stat) +/- 0.09(syst).Comment: 9 pages, 2 figures, accepted for publication in Physical Review Letter

    Measurement of the CP Violation Parameter sin(2phi_1) in B^0_d Meson Decays

    Get PDF
    We present a measurement of the Standard Model CP violation parameter sin(2phi_1) based on a 10.5 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. One neutral B meson is reconstructed in the J/psi K_S, psi(2S) K_S, chi_{c1} K_S, eta_c K_S, J/psi K_L or J/psi pi^0 CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin(2phi_1) = 0.58 +0.32-0.34 (stat) +0.09-0.10 (syst).Comment: LaTex, 13 pages, 3 figures, submitted to P.R.

    An Improved Measurement of Mixing-induced CP Violation in the Neutral B Meson System

    Get PDF
    We present an improved measurement of the standard model CP violation parameter sin2phi_1 (also known as sin2beta) based on a sample of 85 times 10^6 B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. One neutral B meson is reconstructed in a J/psi K_S, psi(2S) K_S, chi_{c1} K_S, eta_c K_S, J/psi K^{*0}, or J/psi K_L CP-eigenstate decay channel and the flavor of accompanying B meson is identified from itsdecay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we obtain sin2phi_1 = 0.719 +/- 0.074(stat) +/- 0.035(syst). We also report measurements of CP violation parameters for the related B^0 -> J/psi pi^0 decay mode and the penguin-dominated processes B^0 -> eta' K_S, phi K_S and K^+K^- K_S.Comment: 11 pages, 4 figures, 4 tables, contributed to ICHEP200

    Genomic organisation and alternative splicing of mouse and human thioredoxin reductase 1 genes

    Get PDF
    BACKGROUND: Thioredoxin reductase (TR) is a redox active protein involved in many cellular processes as part of the thioredoxin system. Presently there are three recognised forms of mammalian thioredoxin reductase designated as TR1, TR3 and TGR, that represent the cytosolic, mitochondrial and novel forms respectively. In this study we elucidated the genomic organisation of the mouse (Txnrd1) and human thioredoxin reductase 1 genes (TXNRD1) through library screening, restriction mapping and database mining. RESULTS: The human TXNRD1 gene spans 100 kb of genomic DNA organised into 16 exons and the mouse Txnrd1 gene has a similar exon/intron arrangement. We also analysed the alternative splicing patterns displayed by the mouse and human thioredoxin reductase 1 genes and mapped the different mRNA isoforms with respect to genomic organisation. These isoforms differ at the 5' end and encode putative proteins of different molecular mass. Genomic DNA sequences upstream of mouse exon 1 were compared to the human promoter to identify conserved elements. CONCLUSIONS: The human and mouse thioredoxin reductase 1 gene organisation is highly conserved and both genes exhibit alternative splicing at the 5' end. The mouse and human promoters share some conserved sequences
    corecore