Browsing by Subject "Antiradical"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Publication
    Open Access
    Characterization of betalains, saponins and antioxidant power in differently colored quinoa (Chenopodium quinoa) varieties
    (Elsevier, 2017-05-02) Jiménez-Atiénzar, Mercedes; Ibáñez-Tremolada, Martha; Gómez-Pando, Luz Rayda; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Quinoa was the traditional grain crop used by the prehispanic civilizations in America. Grains are white, black, yellow, and red-violet and plants are cultivated in vast areas of Peru, Bolivia and Ecuador. The recent description of the betacyanin pigment betanin in red-violet varieties is here further analyzed detecting the presence of amaranthin not previously identified in quinoa grains. Yellow-orange grains are characterized for the first time and up to four different betaxanthins are found to be responsible for this coloration. The native fluorescence of the identified betaxanthins makes the surface of the yellow quinoa grains glow with green fluorescent light. The presence of betalains is correlated with high antioxidant and free radical scavenging activities measured under the FRAP, ABTS and ORAC assays in grain extracts of 29 Peruvian varieties. TEAC equivalence is as high as 44.1 and 47.4 mmol Trolox/kg for the yellow and red-violet varieties analyzed respectively.
  • Thumbnail Image
    Publication
    Embargo
    Production of dihydroxylated betalains and dopamine in cell suspension cultures of Celosia argentea var. plumosa
    (American Chemical Society, 2015-03-01) Guadarrama-Flores, Berenice; Rodríguez-Monroy, Mario; Cruz-Sosa, Francisco; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Betalains are plant pigments of hydrophilic nature with demonstrated chemopreventive potential in cancer celllines and animal models. Among the betalains, those containing an aromatic moiety with two free hydroxyl groups possess thestrongest antioxidant and free radical scavenging activities. The betaxanthins dopaxanthin and miraxanthin V and the betacyaninsbetanidin and decarboxy-betanidin are the only natural betalains with catecholic substructures. These four pigments have beenproduced in cell cultures established from hypocotyls of the plant Celosia argentea. Two stable and differentially colored cell lines,yellow and red, were maintained on Murashige and Skoog medium supplemented with the plant growth regulators 6-benzylaminopurine (6.66 μM) and 2,4-dichlorophenoxyacetic acid (6.79 μM). Derived suspension cultures showed increasedproduction of dihydroxylated betalains in the cells and secreted to the medium with a maximum reached after 8 days of culture.In addition, precursor molecules betalamic acid and dopamine, with content up to 42.08 mg/g dry weight, were also obtained.The joint presence of the bioactive betalains together with the production of dopamine and betalamic acid show the ability of cellcultures of C. argentea to become a stable source of valuable phytochemicals
  • Thumbnail Image
    Publication
    Embargo
    Structural implications on color, fluorescence, and antiradical activity in betalains
    (2010-05-14) Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Departamento de Bioquímica y Biología Molecular A; Facultad de Veterinaria
    Betalains are water-soluble pigments with high antiradical capacity which bestow bright colors on Xowers and fruits of most plants of the order Caryophyllales. They are classiWed as betacyanins, exhibiting a violet coloration, and betaxanthins, which exhibit yellow coloration. Traditionally, betalains have been defined as condensation products of betalamic acid with different amines and amino acids, but the implication of the pigment structure for their properties has not been investigated. This paper explores different structural features of the betalains, revealing the clues for the switch from yellow to violet color, and the loss of fluorescence. A relevant series of 15 betalain-related compounds (both natural and novel semisynthetic ones) is obtained and characterized by chromatography, UV-vis spectrophotometry, fluorescence, and electrospray ionization mass spectroscopy. Antiradical properties of individual pure compounds in a broad pH range are studied under the ABTS•+ radical assay. Relevance of specific bonds is studied, and diferences between betaxanthins and betacyanins are used to explore in depth the structure–antiradical activity relationships in betalains.