Examinando por Materia "antioxidant"

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    Caracterización química y evaluación de la actividad biológica de extractos de Gliricidia sepium con variación latitudinal
    (2018) Franco Leyva, Ana Maria de los Angeles; Marín Palacio, Luz Deisy
    Recently, Bioactive compounds of plants have recently been studied because of their multiple benefits. In this sense, the biological activity of Gliricidia sepium taken from of three different altitudes (0, 800 y 1500 m.a.s.l) of Colombian tropic has been tested. In the present study three solvents (Ethanol, Ethanol-Water and Water) were evaluated for the solid-liquid conventional extraction with two solids charges (1:4 and 1:8) and supercritical CO2 extraction. The highest yields of extraction were obtained with the hydroethanolic extraction treatment and 800 m.a.s.l (273.07± 6.52 mg/g on average). Additionally, phenol, flavonoids and terpenoids were quantified in which the Ethanolic extraction with solid charge of 1:8 and 0 m.a.s.l presented the highest concentrations (79.9±2.5 ppm, 112.1±4.8 ppm y 640.9 ±15.9 ppm respectively). Additionally, the treatment with the highest antioxidant activity (ORAC) corresponded to the one performed with a solid charge of 1:8 in ethanol and 800 m.a.s.l (1919.4 µM de TE/g). At the same time the antioxidant activity results of extraction with supercritical CO2 reached concentration of 677.9; 864.9; 939.6 µM de TE/g 0, 800 Y 1500 m.a.s.l respectively. Finally, the antimicrobial activity of extracts was tested in different microorganisms, the highest inhibition was the one presented against Ralstonia solanacearum EAP09 with inhibition percentage of 90.11±11.20% after 48 hours of exposure. This results permit lead us to the conclusion that ethanolic extract with solids charge 1:8 of G. sepium collected to 800 m.a.s.l present the highest biologic activity, proposing the extracts of the plant as possible source of antioxidant and antimicrobial compounds. Key
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    Paracoccidioides spp. catalases and their role in antioxidant defense against host defense responses
    (Elsevier, 2017-03-01) Tamayo, D.; Muñoz, J.F.; Almeida, A.J.; Puerta, J.D.; Restrepo, Á.; Cuomo, C.A.; McEwen, J.G.; Hernández, O.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Dimorphic human pathogenic fungi interact with host effector cells resisting their microbicidal mechanisms. Yeast cells are able of surviving within the tough environment of the phagolysosome by expressing an antioxidant defense system that provides protection against host-derived reactive oxygen species (ROS). This includes the production of catalases (CATs). Here we identified and analyzed the role of CAT isoforms in Paracoccidioides, the etiological agent of paracoccidioidomycosis. Firstly, we found that one of these isoforms was absent in the closely related dimorphic pathogen Coccidioides and dermatophytes, but all of them were conserved in Paracoccidioides, Histoplasma and Blastomyces species. We probed the contribution of CATs in Paracoccidioides by determining the gene expression levels of each isoform through quantitative RT-qPCR, in both the yeast and mycelia phases, and during the morphological switch (transition and germination), as well as in response to oxidative agents and during interaction with neutrophils. PbCATP was preferentially expressed in the pathogenic yeast phase, and was associated to the response against exogenous H2O2. Therefore, we created and analyzed the virulence defects of a knockdown strain for this isoform, and found that CATP protects yeast cells from H2O2 generated in vitro and is relevant during lung infection. On the other hand, CATA and CATB seem to contribute to ROS homeostasis in Paracoccidioides cells, during endogenous oxidative stress. CAT isoforms in Paracoccidioides might be coordinately regulated during development and dimorphism, and differentially expressed in response to different stresses to control ROS homeostasis during the infectious process, contributing to the virulence of Paracoccidioides. © 2017 Elsevier Inc.