Escribano Cebrián, Josefa

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Escribano Cebrián, Josefa

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Escribano Cebrián, Josefa

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Universidad de Murcia. Departamento de Bioquímica y Biología MolecularA

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Open Access
Light emission in betalains: from fluorescent flowers to biotechnological applications
(Cell Press, 2020-02) Guerrero Rubio, María Alejandra; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular A
The discovery of visible fluorescence in the plant pigments betalains revealed the existence of fluorescent patterns in flowers of plants of the order Caryophyllales, where betalains substitute anthocyanins. The serendipitous initial discovery led to a systemized characterization of the role of different substructures on the photophysical phenomenon. Strong fluorescence is general to all members of the family of betaxanthins linked to the structural property that the betalamic acid moiety is connected to an amine group. This property has led to bioinspired tailor-made probes and to the development of novel biotechnological applications in screening techniques or microscopy labeling. Here, we comprehensively review the photophysics, photochemistry, and photobiology of betalain fluorescence and describe all current applications.
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A continuous spectrophotometric assay for determination of the aureusidin synthase activity of tyrosinase
(Wiley, 2010-04-13) Jiménez-Atiénzar, Mercedes; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; Pérez Gilabert, Manuela; García Carmona, Francisco; Departamento de Bioquímica y Biología Molecular "A"
Introduction – Aurones (aureusidin glycosides) are plant flavonoids that provide yellow colour to the flowers of some orna-mental plants. In this study we analyse the capacity of tyrosinase to catalyse the synthesis of aureusidin by tyrosinase fromthe chalcone THC (2′,4′,6′,4–tetrahydroxychalcone).Objective – To develop a simple continuous spectrophotometric assay for the analysis of the spectrophotometric and kineticcharacteristics of THC oxidation by tyrosinase.Methodology – THC oxidation was routinely assayed by measuring the increase in absorbance at 415 nm vs. reaction time.Results – According to the mechanism proposed for tyrosinase, the enzymatic reaction involves the o-hydroxylation of themonophenol THC to the o-diphenol (PHC, 2′,4′,6′,3,4 – pentahydroxychalcone), which is then oxidised to the correspondingo-quinone in a second enzymatic step. This product is highly unstable and thus undergoes a series of fast chemical reactionsto produce aureusidin. In these experimental conditions, the optimum pH for THC oxidation is 4.5. The progress curvesobtained for THC oxidation showed the appearance of a lag period. The following kinetic parameters were also determined:Km = 0.12 mM , Vm = 13 mM /min, Vm/Km = 0.11/min.Conclusion – This method has made it possible to analyse the spectrophotometric and kinetic characteristics of THC by tyro-sinase. This procedure has the advantages of a short analysis time, straightforward measurement techniques and repro-ducibility. In addition, it also allows the study of tyrosinase inhibitors, such as tropolone.
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Purification and antiradical properties of the structural unit of betalains
(American Chemical Society, 2012-05-29) Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Departamento de Bioquímica y Biología Molecular "A"
Betalamic acid [4-(2-oxoethylidene)-1,2,3,4-tetrahydropyridine2,6-dicarboxylic acid] is a naturally occurring compound that is normally found condensed with amino acids, amines, cyclo-DOPA, and cyclo-DOPA derivatives to form the betalains. Betalains are the pigments responsible for the yellow to violet color of the fruits and flowers of plants belonging to the order Caryophyllales. Betalamic acid is the structural feature common to all of these pigments and contains the electron resonance system responsible for the spectroscopic properties. Betalamic acid was purified by chromatography and identified by UV−vis spectrophotometry and ESI mass spectrometry. The antioxidant and free radical scavenging capacities of betalamic acid were assessed using the FRAP and ABTS·+ radical assays. A pKa of 6.8 was found for the deprotonation equilibrium involved in the nucleophilic activity of betalamic acid; this pKa explains the observed pH effect on the free radical scavenging capacity of these pigments
Open Access
Encapsulation of the Most Potent Antioxidant Betalains in Edible Matrixes as Powders of Different Colors
(2013-05-08) Jiménez-Atiénzar, Mercedes; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular A; Facultades,Servicios y Escuelas::Facultades de la UMU::Facultad de Veterinaria
Betalains are plant pigments with high antioxidant and free radical scavenging activities. While basal activity exists in all betalains, the dihydroxylated molecules present the highest TEAC values of the family of compounds. However, their lability limits possible applications. This work reports the encapsulation of the most active pigments, the yellow miraxanthin V and the violet betanidin in edible matrixes of chitosan and maltodextrin. An appropriate spray-drying procedure is described, with an inlet air temperature of 140 °C. The resulting particles were characterized by scanning electron microscopy, and powder color was analyzed by spectrophotometry using an integrating sphere. Stability of the bioactive compounds was followed by highperformance liquid chromatography, and it was highly promoted by encapsulation, with limited pigment loss after six months’ storage. Particles retained the antioxidant and antiradical activities of the soluble pigments measured under the FRAP and ABTS radical assays. A combination of miraxanthin V and betanidin in variable proportions provides a bright palette of encapsulated powders of different colors suitable for food applications
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Estudio cinético de reacciones acopladas : aplicación a los mecanismos de fosfatasa ácida, peroxidasa, tirosinasa y xatín-oxidasa / Josefa Escribano Cebrián ; Dirección Francisco García Carmona, Francisco García Cánovas.
(Murcia : Universidad, Facultad de Ciencias,, 1986) Escribano Cebrián, Josefa
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.
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One-Step synthesis of betalains using a novel betalamic acid derivatized support
(American Chemical Society, 2014-04-01) Jiménez-Atiénzar, Mercedes; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
Betalains are plant pigments with high antioxidant and cancer hemopreventive properties used by the food industry as safe colorants. Betalains are restricted to species of the order Caryophyllales, and difficulty in obtaining individual molecules has limited their structural identification and application. This study was designed to develop a betalamic acid derivatized support generated from a primary amine polymer. The novel material presents color properties of a pseudobetaxanthin, and it is stable for at least 6 months. The bond formed can be displaced at mild conditions by the addition of amines in aqueous solutions over a broad pH range and at 25 °C. This releases the betalamic acid while forming the corresponding pigment. This one-step procedure significantly simplifies the process of obtaining semisynthetic betalains, and it is optimized here for the formation of betaxanthins and betacyanins derived from tyramine, dopamine, pyrrolidine, and indoline. The new method makes access to single betalains available to the entire scientific community and could stimulate research and applications in the field.
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Betalain health-promoting effects after ingestion in Caenorhabditis elegans are mediated by DAF-16/FOXO and SKN-1/Nrf2 transcription factors
(Elsevier, 2020-06-05) Guerrero Rubio, M. Alejandra; Jiménez Atiénzar, Mercedes; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; García Carmona, Francisco; Hernández García, Samanta; Bioquímica y Biología Molecular A
Betalain-rich extracts have been used for many years by their nutraceutical potential. However, the study of their bioactivities has always been hampered by their difficult obtention. To explain their mode of action, seventeen pure betalains were tested in vivo using the animal model C. elegans. Four betalains, named indicaxanthin, indoline carboxylic acid-betacyanin, phenylalanine-betaxanthin, and dopaxanthin, behaved as extraordinary in vivo antioxidants and anti-aging compounds, by increasing the lifespan of C. elegans up to 16.82%, 16.65%, 16.53%, and 12.93%, respectively. The first microarrays performed with betalains and biological confirmation with different mutant strains showed that this life extension is due to a reduction of oxidative stress and the activation of the transcription factors DAF-16/FOXO and SKN-1/Nrf2. They are involved in longevity and oxidative stress resistance pathways and lead to overexpression of HSPs genes, involved in resistance to cancer and Alzheimer's, opening novel research lines in the search for effective plant-based treatments.
Open Access
Fluorescent Bioinspired Protein Labeling with Betalamic Acid. Derivatization and Characterization of Novel Protein-Betaxanthins
(2016-10) Francisco, García-Carmona; Mercedes, Jiménez-Atiénzar; Cabanes Cos, Juana; Escribano Cebrián, Josefa; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
Betaxanthins are the water-soluble pigments that bestow yellow coloration to fruits, flowers and roots of plants of the Caryophyllales order and present autofluorescence after excitation with blue light. In this work, the semi-synthesis of betaxanthins derived from macromolecules is achieved for the first time by exploiting the reactivity of amine groups belonging to proteins. The synthesis of protein-betaxanthins is demonstrated by spectrophotometry and HPLC-ESI-TOF-MS mass analysis. The derivatization with betalamic acid was in a ratio 1:1 and yielded protein-betaxanthins yellow in color that exhibited fluorescent properties with a maximum excitation wavelength of 476 nm and a maximum emission wavelength of 551 nm. Moreover, staining can be started from purified betalamic acid or directly from raw red beet root extracts. The novel bioinspired labeling reaction allowed protein detection in conventional fluorescence scanning and imaging systems and opens a new perspective for betalamic acid derived molecules as fluorescent probes with multiple biological applications.
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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.