Grupo de Investigacion en Polifenoles

Villanueva del Río y Minas, Spain

Grupo de Investigacion en Polifenoles

Villanueva del Río y Minas, Spain

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Gonzalez-Manzano S.,Grupo de Investigacion en Polifenoles | Gonzalez-Paramas A.M.,Grupo de Investigacion en Polifenoles | Delgado L.,Grupo de Investigacion en Polifenoles | Patianna S.,Grupo de Investigacion en Polifenoles | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2012

The aim of this work was to examine the mechanisms involved in the in vivo antioxidant effects of epicatechin (EC), a major flavonoid in the human diet. The influence of EC in different oxidative biomarkers (reactive oxygen species (ROS) production, intracellular glutathione, activity of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)) was studied in the model organism Caenorhabditis elegans. Under thermal stress condition, exposure of the worms (wild type N2 strains) to EC (200 μM) significantly reduced ROS levels (up to 28%) and enhanced the production of reduced glutathione (GSH). However, no significant changes were appreciated in the activities of GPx, CAT, and SOD, suggesting that further activation of these antioxidant enzymes was not required once the concentration of ROS in the EC-treated worms was restored to what could be considered physiological levels. © 2012 American Chemical Society.


Delgado L.,Grupo de Investigacion en Polifenoles | Fernandes I.,University of Porto | Gonzalez-Manzano S.,Grupo de Investigacion en Polifenoles | De Freitas V.,University of Porto | And 2 more authors.
Food and Function | Year: 2014

Dietary flavonoids have been associated with a lower incidence of some chronic diseases. However, the mechanisms behind the in vivo biological activity of flavonoids are still mostly unknown. Flavonoids are metabolized in the human body to conjugated forms (methylated, sulphated and glucuronidated derivatives) that should play a role in flavonoid activity. In this study, the anti-proliferative effects of conjugated metabolites of quercetin and (epi)catechin, major flavonoids in the diet, have been evaluated against three different cancer cell lines from breast (MCF-7), colon (Caco-2) and pancreas (BxPC-3) and one normal cell line of human foreskin fibroblasts (HFF-1), and compared with the effect of their unconjugated forms. Quercetin showed anti-proliferative activity on the three assayed cell models, whereas catechin and epicatechin were not active. Methylation on ring-B of quercetin decreased the anti-proliferative effects, especially when the methylation occurred in position 3′ (isorhamnetin), although methylated metabolites still showed significant anti-proliferative activity. As to catechins, 4′-O-methyl- epicatechin and 3′-O-methyl-epicatechin were the only ones to show some activity on MCF-7 and BxPC-3 cell lines, respectively. Conjugation of quercetin with glucose or glucuronic acid eliminated the anti-proliferative effects of aglycones. Sulphated metabolites were also tested and found to be inactive in most of the explored cell lines, although quercetin-4′-O-sulphate and epicatechin-3′-O-sulphate still showed some anti-proliferative activity on MCF-7 and Caco-2 cells, respectively. This journal is © the Partner Organisations 2014.


Duenas M.,Grupo de Investigacion en Polifenoles | Surco-Laos F.,Grupo de Investigacion en Polifenoles | Gonzalez-Manzano S.,Grupo de Investigacion en Polifenoles | Gonzalez-Paramas A.M.,Grupo de Investigacion en Polifenoles | And 3 more authors.
Pharmacological Research | Year: 2013

Due to their purported healthful activities, quercetin and other flavonoids are being increasingly proposed as nutraceuticals. Quercetin occurs in food as glycosides; however, most assays on its activity have been performed with the aglycone, despite glycosylation deeply affects compound bioavailability. In this work, the uptake and lifespan effects of quercetin-3-O-glucoside (Q3Glc) and quercetin have been assessed in Caenorhabditis elegans. Q3Glc was taken up by this nematode in a concentration-dependent manner and rapidly deglycosylated to quercetin, which was accumulated in the worm and partially biotransformed to conjugated metabolites. Significant mean lifespan extension up to 23% compared to controls was observed in wild type worms cultivated in the presence of low concentrations of Q3Glc (10 μM and 25 μM), whereas exposure to greater concentrations of Q3Glc (50-200 μM) caused a reduction in mean and maximum lifespan compared with the control. By contrast, treatment of klo-1 and klo-2 mutant worms lacking β-glucosidase activity with 200 μM of Q3Glc led to extended mean lifespan (up to 39%), similar to quercetin aglycone at the same concentration levels. In those mutants, Q3Glc was accumulated without important deglycosylation to quercetin was produced. Taken together, these findings indicated that Q3Glc was taken up by the nematode in greater extent than quercetin, and that deglycosylation and subsequent aglycone accumulation in the worm appeared as key points to explain the observed lifespan effects. The obtained results also suggested that facilitated absorption should be more important for the uptake of quercetin derivatives than passive diffusion. © 2013 Elsevier Ltd. All rights reserved.


Garcia-Marino M.,Grupo de Investigacion en Polifenoles | Hernandez-Hierro J.M.,Grupo de Investigacion en Polifenoles | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Escribano-Bailon M.T.,Grupo de Investigacion en Polifenoles
Analytica Chimica Acta | Year: 2010

The Vitis vinifera L. cv Graciano is often used as an integral component of Rioja wines because it is considered to contribute significantly to the quality of Tempranillo based wines. The aim of this work was to determine the effect of the incorporation of the Graciano variety on the colour and pigment composition of Tempranillo based wine and to evaluate the possible differences between blending Tempranillo with Graciano varietal wine (W wine) in contrast to a wine obtained by mixing these two grape varieties in the prefermentative maceration step (M wine). Results indicated that pigment extraction and retention in M wine was higher than in Tempranillo (T) wine. Colour differences (Δ Eab *) between wines at the end of the study (after 12 months in bottles) were detectable by the human eye (Δ Eab * ≥ 3) in all cases except for T and W. These wines have indistinguishable colours even when using analytical methods (Δ Eab * ≤ 1). Regarding hue hab, T and W presented higher values (more orange-red) than Graciano (G) and M (more blue-red). PCA allowed the colour and composition analytical data to be reduced to a small number of principal components that could separate successfully between T and G wines and between the different steps of the winemaking process. © 2009 Elsevier B.V. All rights reserved.


Ferrer-Gallego R.,Grupo de Investigacion en Polifenoles | Garcia-Marino M.,Grupo de Investigacion en Polifenoles | Miguel Hernandez-Hierro J.,Grupo de Investigacion en Polifenoles | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Teresa Escribano-Bailon M.,Grupo de Investigacion en Polifenoles
Analytica Chimica Acta | Year: 2010

The aim of this work has been to determine the correlations between sensory analysis, colour and content of main flavanols present in seeds. For this, the flavanic composition of grape seeds with different degrees of maturity was analysed by HPLC-DAD-MS and the obtained results were correlated with CIELab colour parameters, perceived colour (C), hardness of the seed (HS), tannic intensity (TI) and astringency (A). Multiple linear regression analysis (MLR) with the variables showing significant correlations (p < 0.05) was also performed. Grape seeds undergo important decreases in the content of catechins and procyanidin oligomers during ripening. Epicatechin-(4-8)-epicatechin-3-O-gallate (B2G) and (-)-epicatechin-3-O-gallate (ECG) are the flavanolic compounds whose contents decrease most. The changes in the phenolic composition accompany changes in TI, A and HS. The total content of flavanols in the seed is not the only factor affecting these attributes, since samples containing higher contents in flavanols can exhibit less astringency and tannic intensity than others with lower ones. The qualitative profile of the seeds is, therefore, also responsible for the sensations elicited in the mouth. A and HS parameters are more affected by the presence of galloylated dimeric procyanidins in the molecule than TI. CIELab colour parameters of seeds have high correlation coefficients with many flavanolic compounds. ECG was the compound most related to these parameters. © 2009 Elsevier B.V. All rights reserved.


Ferrer-Gallego R.,Grupo de Investigacion en Polifenoles | Hernandez-Hierro J.M.,Grupo de Investigacion en Polifenoles | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Escribano-Bailon M.T.,Grupo de Investigacion en Polifenoles
CYTA - Journal of Food | Year: 2011

The aim of this work was to evaluate sensory changes in grape skins during ripening and to obtain a correlation with their phenolic composition. Flavan-3-ols (monomers and dimers), prodelphinidins, hydroxybenzoic acids, hydroxycinnamic acids, anthocyanins and flavonols were determined by HPLC-DAD-MS. In addition, skin dilaceration, tannic intensity, astringency, acidity, aroma intensity (AI) and type of aroma were evaluated. Multivariate analysis showed the evolution of these samples during ripening and the relationship among sensory scores and phenolic composition of grapes skins. Skin dilaceration, type of aroma and to a lesser extent AI tend to increase during ripening. The contents in the phenolic compounds in grape skins present a similar pattern to the aforementioned sensory parameters. Nevertheless, tannic intensity, astringency, dryness and acidity present an opposite pattern which indicates a decrease of these sensory scores during ripening. © 2011 Taylor & Francis.


Santos-Buelga C.,Grupo de Investigacion en Polifenoles | Mateus N.,University of Porto | De Freitas V.,University of Porto
Journal of Agricultural and Food Chemistry | Year: 2014

Anthocyanins are plant pigments widespread in nature. They play relevant roles in plant propagation and ecophysiology and plant defense mechanisms and are responsible for the color of fruits and vegetables. A large number of novel anthocyanin structures have been identified, including new families such as pyranoanthocyanins or anthocyanin oligomers; their biosynthesis pathways have been elucidated, and new plants with "a la carte" colors have been created by genetic engineering. Furthermore, evidence about their benefits in human health has accumulated, and processes of anthocyanin absorption and biotransformation in the human organism have started to be ascertained. These advances in anthocyanin research were revised in the Seventh International Workshop on Anthocyanins that took place in Porto (Portugal) on September 9-11, 2013. Some selected papers are collected in this special issue, where aspects such as anthocyanin accumulation in plants, relationship with color expression, stability in plants and food, and bioavailability or biological activity are revised. © 2014 American Chemical Society.


Ferrer-Gallego R.,Grupo de Investigacion en Polifenoles | Hernandez-Hierro J.M.,Food Colour and Quality Laboratory | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Escribano-Bailon M.T.,Grupo de Investigacion en Polifenoles
Journal of Food Engineering | Year: 2013

Grape seed and skin sensory parameters are important characteristics in making decisions concerning the optimal harvest time and producing high-quality red wines. The potential of near infrared spectroscopy to determine several sensory parameters of seeds and skins was evaluated. Taste (sourness), texture (astringency, tannic intensity, dryness and hardness), visual (colour) and olfactory (intensity and type of aroma) attributes were considered. Calibration models were performed by modified partial least squares regression. The differences between sensory analysis and NIRS analysis in external validation were lower in the case of seeds; they were between 4.5% for hardness and 8.7% for colour. For the skins, differences in external validation were between 9.8% for tannic intensity and 13.7% for astringency. The results obtained show that NIRS technology has considerable potential for predicting the above sensory attributes. © 2013 Elsevier Ltd. All rights reserved.


Ferrer-Gallego R.,Grupo de Investigacion en Polifenoles | Hernandez-Hierro J.M.,Grupo de Investigacion en Polifenoles | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Escribano-Bailon M.T.,Grupo de Investigacion en Polifenoles
Talanta | Year: 2010

The potential of near infrared spectroscopy to determine the content of flavanols directly recording the infrared spectra of grape seeds has been evaluated. Moreover, the study shows the potential of this technique to obtain qualitative information related to the samples. In this case, the feasibility to discriminate between possible vineyards of origin has also been evaluated. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models in order to predict the content of flavanols. These models have been validated showing differences between 3.5% and 14.3% in the external validation. Moreover, Discriminant Partial Least Squares algorithm was used in the qualitative analysis to distinguish between two possible vineyards of origin and showed a high degree of accuracy. Prediction rates of samples correctly classified with a mean of 95% in internal validation and 97% in external validation were obtained. The procedure reported here seems to have an excellent potential for a fast and reasonably inexpensive analysis of these flavanols in grape seeds and could also be a tool to distinguish between possible vineyards of origin. © 2010 Elsevier B.V.


Ferrer-Gallego R.,Grupo de Investigacion en Polifenoles | Goncalves R.,University of Porto | Rivas-Gonzalo J.C.,Grupo de Investigacion en Polifenoles | Escribano-Bailon M.T.,Grupo de Investigacion en Polifenoles | De Freitas V.,University of Porto
Food Chemistry | Year: 2012

The ability of grape seed extracts to bind to bovine serum albumin (BSA) and α-amylase was studied by fluorescence quenching of protein intrinsic fluorescence and nephelometry. The influence of grape seed ripeness on astringency was also evaluated. From the spectra obtained, the modified Sterm-Volmer (Kapp) and the bimolecular quenching constants were calculated. Results showed that grape seed extracts had good affinity for proteins. The association strength of tannin-protein interactions varied with changes in tannin structure associated with the degree of ripeness affecting the binding/quenching process. In all cases studied, higher values of K app were obtained in samples at harvest which have greater ability to bind to proteins than have samples at post-veraison time. Nephelometric assays show the same trend as do fluorescence quenching studies. A possible explanation for this is that, as seeds ripen, their tannins increase in molecular mass, which relates to an increase in hydrophobicity of the molecules, and this increases protein affinity. However, that is contrary to the reported decrease in astringency of grape seeds during maturity. This indicates that tannin-protein interactions are not the only explanation for the complex sensations of astringency of grape seeds. © 2012 Elsevier Ltd. All rights reserved.

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