Browsing by Autor "Akesson, Bjorn"

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    A 5-METHYLCOUMARIN GLUCOSIDE AND A COUMESTAN DERIVATIVE FROM MUTISIA ORBIGNYANA
    (Rev. Bol. Quim, 2009) Flores, Yonny; Rodrigo, Gloria; Mollinedo, Patricia; Akesson, Bjorn; Sterner, Olov; Almanza, Giovanna R
    El extracto etanólico de las partes aéreas de Mutisia orbignyana presentó dos compuestos mayoritarios: mutisifurocumarina (1) y 5-metilcumarina-4-β-glucosilada (2). El asignamiento completo de RMN de ¹H y 13C del compuesto (2) es presentado por primera vez, así como también algunos reasignamientos del espectro de RMN13C del compuesto (1), en ambos casos se aplico técnicas de RMN 2D. Además, se midió el efecto antiproliferativo sobre células cancerosas de colon (CaCo2) y el efecto como inhibidores de radicales libres usando la prueba ABTS, tanto de extractos como de compuestos puros. Los resultados muestran un interesante efecto antiradicalario en ABTS y un efecto no-proliferativo sobre células cancerosas de colon
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    Antioxidant and antimutagenic polyisoprenylated benzophenones and xanthones from Rheedia acuminata.
    (2011) Almanza, Giovanna R; Quispe, Raúl; Mollinedo, Patricia; Rodrigo, Gloria; Fukushima, Odette; Villagomez, Rodrigo; Akesson, Bjorn; Sterner, Olov
    Dichloromethane extract of the stem bark of Rheedia acuminata yielded three benzophenones with antioxidant activity, the new one named acuminophenone A (1), guttiferone K (2) and isoxanthochymol (3), along with the known xanthones formoxanthone C (4) and macluraxanthone (5). The structures were established through interpretation of their spectroscopic data, the stereochemistry of compounds (1) and (2) were resolved by experimental and computational experiments and their antioxidant activities were measured using the DPPH, ABTS and TEAC assays. The antioxidant results showed that metabolites 1, 4 and 5 had a better antioxidant activity than the reference compound quercetin. In addition, we evaluate the mutagenicity and antimutagenicity of the CH2Cl2 extract as well as of the free radical scavenger compounds 1, 4 and 5 by the AMES Salmonella/microsomal test. No mutagenicity was found in the CH2Cl2 extract using Salmonella typhimurium strains TA98, TA100, TA102, TA1537 and TA1538, with or without S9 metabolic activation. The pure compounds neither showed mutagenicity in TA 102 strain and the most important result was the strong reduction of mutagenic effect induced by hydrogen peroxide in S. typhimurium TA102, with or without S9, showed by the compounds 1 (more than 93%) and 4 (more than 88%) at 0.02 microg/plate.