Publications by authors named "Concepcion Cid"

24 Publications

  • Page 1 of 1

Bioaccessibility of Tudela artichoke (Cynara scolymus cv. Blanca de Tudela) (poly)phenols: the effects of heat treatment, simulated gastrointestinal digestion and human colonic microbiota.

Food Funct 2021 Mar 4;12(5):1996-2011. Epub 2021 Feb 4.

Universidad de Navarra, Facultad de Farmacia y Nutrición, Departamento de Ciencias de la Alimentación y Fisiología, C/Irunlarrea 1, E-31008 Pamplona, Spain.

The aim of this study was to evaluate the bioaccessibility of (poly)phenolic compounds in Tudela artichokes (Cynara scolymus cv. Blanca de Tudela) after an in vitro gastrointestinal digestion and the effect of the human colonic microbiota. A total of 28 (poly)phenolic compounds were identified and quantified by LC-MS/MS in raw, boiled, sous vide and microwaved Tudela artichokes. Out of these, sixteen were phenolic acids, specifically caffeoylquinic acids (CQAs) and other minor hydroxycinnamic acid derivatives, ten flavonoids belonging to the family of flavones (apigenin and luteolin derivatives) and two lignans (pinoresinol derivatives). Sous vide and microwaving caused mainly transesterification reactions of CQAs but maintained or even augmented the total (poly)phenolic contents of artichokes, while boiling decreased (poly)phenolic compounds by 25% due to leaching into the boiling water. Heat treatment exerted a positive effect on the bioaccessibility of (poly)phenols after gastrointestinal digestion. In raw artichokes, only 1.6% of the total (poly)phenolic compounds remained bioaccessible after gastrointestinal digestion, while in artichoke samples cooked by sous vide, boiled and microwaved, the percentage of bioaccessibility was 60.38%, 59.93% and 39,03% respectively. After fecal fermentation, 20 native (poly)phenolic compounds and 11 newly formed catabolites were quantified. 48 h of fecal fermentation showed that native (poly)phenols are readily degraded by colonic microbiota during the first 2 h of incubation. The colonic degradation of artichoke (poly)phenols follows a major pathway that involves the formation of caffeic acid, dihydrocaffeic acid, 3-(3'-hydroxyphenyl)propionic acid, 3-phenylpropionic acid and phenylacetic acid, with 3-phenylpropionic acid being the most abundant end product. The catabolic pathways for colonic microbial degradation of artichoke CQAs are proposed.
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http://dx.doi.org/10.1039/d0fo03119dDOI Listing
March 2021

Quantitative Assessment of Dietary (Poly)phenol Intake: A High-Throughput Targeted Metabolomics Method for Blood and Urine Samples.

J Agric Food Chem 2021 Jan 29;69(1):537-554. Epub 2020 Dec 29.

Department of Nutritional Sciences, School of Life Course Sciences, Faculty of Life Science and Medicine, King's College London, London SE1 9NH, U.K.

Many studies have associated the consumption of (poly)phenol-rich diets with health benefits. However, accurate high-throughput quantitative methods for estimating exposure covering a broad spectrum of (poly)phenols are lacking. We have developed and validated a high-throughput method for the simultaneous quantification of 119 (poly)phenol metabolites in plasma and urine using ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry, with a very fast sample treatment and a single run time of 16 min. This method is highly sensitive, precise, accurate, and shows good linearity for all compounds ( > 0.992). This novel method will allow a quantitative assessment of habitual (poly)phenol intake in large epidemiological studies as well as clinical studies investigating the health benefits of dietary (poly)phenols.
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http://dx.doi.org/10.1021/acs.jafc.0c07055DOI Listing
January 2021

DNA damage and DNA protection from digested raw and griddled green pepper (poly)phenols in human colorectal adenocarcinoma cells (HT-29).

Eur J Nutr 2021 Mar 19;60(2):677-689. Epub 2020 May 19.

Departamento de Ciencias de la Alimentación y Fisiología, Facultad de Farmacia y Nutrición, Universidad de Navarra, C/Irunlarrea 1, 31008, Pamplona, Spain.

Purpose: To determine whether (poly)phenols from gastrointestinal-digested green pepper possess genoprotective properties in human colon cells and whether the application of a culinary treatment (griddling) on the vegetable influences the potential genoprotective activity.

Methods: (Poly)phenols of raw and griddled green pepper (Capsicum annuum L.) submitted to in vitro-simulated gastrointestinal digestion were characterized by LC-MS/MS. Cytotoxicity (MTT, trypan blue and cell proliferation assays), DNA damage and DNA protection (standard alkaline and formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay) of different concentrations of (poly)phenolic extracts were assessed in colon HT-29 cells.

Results: A total of 32 (poly)phenolic compounds were identified and quantified in digested raw and griddled green pepper. Twenty of them were flavonoids and 12 were phenolic acids. Griddled pepper doubled the (poly)phenol concentration compared to raw; luteolin 7-O-(2-apiosyl)-glucoside and quercitrin constituted the major (poly)phenols in both extracts. Raw and griddled pepper (poly)phenolic extracts impaired cell proliferation and induced low levels of Fpg-sensitive sites, in a dose-dependent manner, even at a non-cytotoxic concentration. None of the concentrations tested induced DNA strand breaks or alkaline labile sites. Nor did they show significant genoprotection against the DNA damage induced by HO or KBrO.

Conclusions: Green pepper (poly)phenols did not show genoprotection against oxidatively generated damage in HT-29 cells at simulated physiological concentrations, regardless of the application, or not, of a culinary treatment (griddling). Furthermore, high concentrations of (poly)phenolic extracts induced a slight pro-oxidant effect, even at a non-cytotoxic concentration.
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http://dx.doi.org/10.1007/s00394-020-02269-2DOI Listing
March 2021

Identification of Small Molecules Disrupting the Ubiquitin Proteasome System in Malaria.

ACS Infect Dis 2019 12 7;5(12):2105-2117. Epub 2019 Nov 7.

Tres Cantos Medicines Development Campus, Diseases of the Developing World . GlaxoSmithKline , Severo Ochoa 2 , Tres Cantos , 28760 Madrid , Spain.

The ubiquitin proteasome system (UPS) is one of the main proteolytic pathways in eukaryotic cells, playing an essential role in key cellular processes such as cell cycling and signal transduction. Changes in some of the components of this pathway have been implicated in various conditions, including cancer and infectious diseases such as malaria. The success of therapies based on proteasome inhibitors has been shown in human clinical trials. In addition to its proven tractability, the essentiality of the UPS underlines its potential as a source of targets to identify new antimalarial treatments. Two assays, previously developed to quantify the parasite protein ubiquitylation levels in a high throughput format, have been used to identify compounds that inhibit parasite growth by targeting UPS. Among the positive hits, specific inhibitors of the proteasome have been identified and characterized. Hits identified using this approach may be used as starting points for development of new antimalarial drugs. They may also be used as tools to further understand proteasome function and to identify new targets in UPS.
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http://dx.doi.org/10.1021/acsinfecdis.9b00216DOI Listing
December 2019

Digestion and Colonic Fermentation of Raw and Cooked Opuntia ficus-indica Cladodes Impacts Bioaccessibility and Bioactivity.

J Agric Food Chem 2019 Mar 25;67(9):2490-2499. Epub 2019 Feb 25.

Universidad de Navarra , Facultad de Farmacia y Nutrición, Departamento de Ciencias de la Alimentación y Fisiología , C/Irunlarrea 1 , E-31008 Pamplona , Spain.

The bioactivity of (poly)phenols from a food is an interplay between the cooking methods applied and the interaction of the food with the gastrointestinal tract. The (poly)phenolic profile and biological activity of raw and cooked cactus ( Opuntia ficus-indica Mill.) cladodes following in vitro digestion and colonic fermentation were evaluated. Twenty-seven (poly)phenols were identified and quantified by HPLC-ESI-MS, with piscidic acid being the most abundant. Throughout the colonic fermentation, flavonoids showed more degradation than phenolic acids, and eucomic acid remained the most relevant after 24 h. The catabolite 3-(4-hydroxyphenyl)propionic acid was generated after 24 h of fermentation. Cytotoxicity, genotoxicity, and cell cycle analyses were performed in HT29 cells. Cactus colonic fermentates showed higher cell viability (≥80%) in comparison to the control fermentation with no cactus and significantly ( p < 0.05) reduced HO-induced DNA damage in HT29 cells. Results suggest that, although phenolic compounds were degraded during the colonic fermentation, the biological activity is retained in colon cells.
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http://dx.doi.org/10.1021/acs.jafc.8b06480DOI Listing
March 2019

Digestibility of (Poly)phenols and Antioxidant Activity in Raw and Cooked Cactus Cladodes ( Opuntia ficus-indica).

J Agric Food Chem 2018 Jun 29;66(23):5832-5844. Epub 2018 May 29.

Universidad de Navarra, Facultad de Farmacia y Nutrición , Departamento de Ciencias de la Alimentación y Fisiología , C/Irunlarrea 1 , E-31008 Pamplona , Spain.

This study aims to investigate whether heat treatment applied to cactus cladodes influences the bioaccessibility of their (poly)phenolic compounds after simulated gastric and intestinal digestion. A total of 45 (poly)phenols were identified and quantified in raw and cooked cactus cladodes by ultra high performance liquid chromatography photodiode array detector high resolution mass spectrometry. Both flavonoids (60-68% total), mainly isorhamnetin derivatives, and phenolic acids (32-40%) with eucomic acids as the predominant ones significantly ( p < 0.05) increased with microwaving and griddling processes. After in vitro gastrointestinal digestion, 55-64% of the total (poly)phenols of cooked cactus cladodes remained bioaccessible versus 44% in raw samples. Furthermore, digestive conditions and enzymes degraded or retained more flavonoids (37-63% bioaccessibility) than phenolic acids (56-87% bioaccessibility). Microwaved cactus cladodes contributed the highest amount of (poy)phenols (143.54 mg/g dm) after gastrointestinal process, followed by griddled samples (133.98 mg/g dm), showing the highest antioxidant capacity. Additionally, gastrointestinal digestion induced isomerizations among the three stereoisomeric forms of piscidic and eucomic acids.
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http://dx.doi.org/10.1021/acs.jafc.8b01167DOI Listing
June 2018

Impact of cooking process on nutritional composition and antioxidants of cactus cladodes (Opuntia ficus-indica).

Food Chem 2018 Feb 15;240:1055-1062. Epub 2017 Aug 15.

Universidad de Navarra, Facultad de Farmacia y Nutrición, Departamento de Ciencias de la Alimentación y Fisiología, C/ Irunlarrea 1, E-31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain. Electronic address:

The impact of cooking methods (boiling, microwaving, griddling and frying in olive and soybean oils) on nutritional composition (protein, minerals, fat, carbohydrates, fibre, fatty acid profile and energy), antioxidant capacity and (poly)phenolic compounds of cactus cladodes (Opuntia ficus-indica) was evaluated. Culinary processes, except boiling, increased soluble and insoluble fibre up to 5.0g/100g becoming a good fibre source. Cactus cladodes fried in olive oil showed a healthier fatty acid profile and lower ω-6/ω-3 ratio than in soybean oil. Flavonoids accounted for 80% of total (poly)phenolic compounds, being isorhamnetin the most abundant. Heat treatment, particularly griddling and microwaving, increased every flavonoid and phenolic acid up to 3.2-fold higher than in raw samples, and consequently their antioxidant capacity. Even boiling induced losses in total (poly)phenols and antioxidant capacity by leaching into water, the main compounds were maintained. Principal Component Analysis distributed heat treated cactus cladodes according to their distinctive polyphenols and antioxidant capacity.
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http://dx.doi.org/10.1016/j.foodchem.2017.08.039DOI Listing
February 2018

Development of a Novel High-Density [3H]Hypoxanthine Scintillation Proximity Assay To Assess Plasmodium falciparum Growth.

Antimicrob Agents Chemother 2016 10 23;60(10):5949-56. Epub 2016 Sep 23.

Platform Technology and Science, Centro de Investigación Básica, GlaxoSmithKline, Tres Cantos, Spain.

The discovery and development of new antimalarial drugs are becoming imperative because of the spread of resistance to current clinical treatments. The lack of robustly validated antimalarial targets and the difficulties with the building in of whole-cell activity in screening hits are hampering target-based approaches. However, phenotypic screens of structurally diverse molecule libraries are offering new opportunities for the identification of novel antimalarials. Several methodologies can be used to determine the whole-cell in vitro potencies of antimalarial hits. The [(3)H]hypoxanthine incorporation assay is considered the "gold standard" assay for measurement of the activity of antimalarial compounds against intraerythrocytic forms of Plasmodium falciparum However, the method has important limitations, as the assay is not amenable for high-throughput screening since it remains associated with the 96-well plate format. We have overcome this drawback by adapting the [(3)H]hypoxanthine incorporation method to a 384-well high-density format by coupling a homogeneous scintillation proximity assay (SPA) and thus eliminating the limiting filtration step. This SPA has been validated using a diverse set of 1,000 molecules, including both a representative set from the Tres Cantos Antimalarial Set (TCAMS) of compounds and molecules inactive against whole cells. The results were compared with those from the P. falciparum lactate dehydrogenase whole-cell assay, another method that is well established as a surrogate for parasite growth and is amenable for high-throughput screening. The results obtained demonstrate that the SPA-based [(3)H]hypoxanthine incorporation assay is a suitable design that is adaptable to high-throughput antimalarial drug screening and that maintains the features, robustness, and reliability of the standard filtration hypoxanthine incorporation method.
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http://dx.doi.org/10.1128/AAC.00433-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5038259PMC
October 2016

A high-throughput fluorescence-based assay for Plasmodium dihydroorotate dehydrogenase inhibitor screening.

Anal Biochem 2016 08 29;506:13-21. Epub 2016 Apr 29.

Platform Technology and Science Tres Cantos, GlaxoSmithKline, Centro de Investigación Básica, 28760, Tres Cantos, Spain. Electronic address:

Plasmodium dihydroorotate dehydrogenase (DHODH) is a mitochondrial membrane-associated flavoenzyme that catalyzes the rate-limiting step of de novo pyrimidine biosynthesis. DHODH is a validated target for malaria, and DSM265, a potent inhibitor, is currently in clinical trials. The enzyme catalyzes the oxidation of dihydroorotate to orotate using flavin mononucleotide (FMN) as cofactor in the first half of the reaction. Reoxidation of FMN to regenerate the active enzyme is mediated by ubiquinone (CoQD), which is the physiological final electron acceptor and second substrate of the reaction. We have developed a fluorescence-based high-throughput enzymatic assay to find DHODH inhibitors. In this assay, the CoQD has been replaced by a redox-sensitive fluorogenic dye, resazurin, which changes to a fluorescent state on reduction to resorufin. Remarkably, the assay sensitivity to find competitive inhibitors of the second substrate is higher than that reported for the standard colorimetric assay. It is amenable to 1536-well plates with Z' values close to 0.8. The fact that the human enzyme can also be assayed in the same format opens additional applications of this assay to the discovery of inhibitors to treat cancer, transplant rejection, autoimmune diseases, and other diseases mediated by rapid cellular growth.
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http://dx.doi.org/10.1016/j.ab.2016.04.013DOI Listing
August 2016

Influence of heat treatment on antioxidant capacity and (poly)phenolic compounds of selected vegetables.

Food Chem 2016 Apr 29;197(Pt A):466-73. Epub 2015 Oct 29.

Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31080 Pamplona, Spain. Electronic address:

The impact of cooking heat treatments (frying in olive oil, frying in sunflower oil and griddled) on the antioxidant capacity and (poly)phenolic compounds of onion, green pepper and cardoon, was evaluated. The main compounds were quercetin and isorhamnetin derivates in onion, quercetin and luteolin derivates in green pepper samples, and chlorogenic acids in cardoon. All heat treatments tended to increase the concentration of phenolic compounds in vegetables suggesting a thermal destruction of cell walls and sub cellular compartments during the cooking process that favor the release of these compounds. This increase, specially that observed for chlorogenic acids, was significantly correlated with an increase in the antioxidant capacity measured by DPPH (r=0.70). Griddled vegetables, because of the higher temperature applied during treatment in comparison with frying processes, showed the highest amounts of phenolic compounds with increments of 57.35%, 25.55% and 203.06% compared to raw onion, pepper and cardoon, respectively.
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http://dx.doi.org/10.1016/j.foodchem.2015.10.139DOI Listing
April 2016

In vitro studies on the stability in the proximal gastrointestinal tract and bioaccessibility in Caco-2 cells of chlorogenic acids from spent coffee grounds.

Int J Food Sci Nutr 2015 23;66(6):657-64. Epub 2015 Jul 23.

c Department of Nutrition , University of California , Davis , CA , USA.

Spent coffee grounds are a potential commercial source of substantial amounts of chlorogenic acids (CGAs). The aim of this study was to evaluate the stability of spent coffee CGAs using in vitro simulated gastroduodenal digestion and to investigate their potential absorption using an in vitro Caco-2 model of human small intestinal epithelium. During in vitro digestion, lactones were partially degraded while caffeoylquinic and feruloylquinic acids were much more stable. Transport and metabolism studies showed that 1% of the total CGAs were absorbed and transported from the apical to the basolateral side of a Caco-2 cell monolayer after 1 h. Lactones and coumaroylquinic acids showed the rate of highest absorption. Caco-2 cells possessed low metabolic activity. In conclusion, spent coffee extracts contain large amounts of CGAs, which remained bioaccessible across the intestinal barrier, albeit to a relatively low degree.
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http://dx.doi.org/10.3109/09637486.2015.1064874DOI Listing
June 2016

Development of two novel high-throughput assays to quantify ubiquitylated proteins in cell lysates: application to screening of new anti-malarials.

Malar J 2015 May 14;14:200. Epub 2015 May 14.

Ubiquitylation and Cancer Molecular Biology, Inbiomed, Mikeletegi 81, 20009, San Sebastian, Spain.

Background: The ubiquitin proteasome system (UPS) is one of the main proteolytical pathways in eukaryotic cells and plays an essential role in key cellular processes such as cell cycle, stress response, signal transduction, and transcriptional regulation. Many components of this pathway have been implicated in diverse pathologies including cancer, neurodegeneration and infectious diseases, such as malaria. The success of proteasome inhibitors in clinical trials underlines the potential of the UPS in drug discovery.

Methods: Plasmodium falciparum, the malaria causative pathogen, has been used to develop two assays that allow the quantification of the parasite protein ubiquitylation levels in a high-throughput format that can be used to find new UPS inhibitors.

Results: In both assays tandem ubiquitin binding entities (TUBEs), also known as ubiquitin traps, have been used to capture ubiquitylated proteins from cell lysates. The primary assay is based on AlphaLISA technology, and the orthogonal secondary assay relies on a dissociation-enhanced lanthanide fluorescent immunoassay (DELFIA) system. A panel of well-known proteasome inhibitors has been used to validate both technologies. An excellent correlation was obtained between these biochemical assays and the standard whole cell assay that measures parasite growth inhibition.

Conclusions: The two assays presented can be used in a high-throughput format to find new UPS inhibitors for P. falciparum and could help to identify new targets within this system. This methodology is also applicable to other cellular contexts or pathologies.
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http://dx.doi.org/10.1186/s12936-015-0708-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4440562PMC
May 2015

Assessment of total (free and bound) phenolic compounds in spent coffee extracts.

J Agric Food Chem 2015 May 24;63(17):4327-34. Epub 2015 Apr 24.

†Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31008 Pamplona, Spain.

Spent coffee is the main byproduct of the brewing process and a potential source of bioactive compounds, mainly phenolic acids easily extracted with water. Free and bound caffeoylquinic (3-CQA, 4-CQA, 5-CQA), dicaffeoylquinic (3,4-diCQA, 3,5-diCQA, 4,5-diCQA), caffeic, ferulic, p-coumaric, sinapic, and 4-hydroxybenzoic acids were measured by HPLC, after the application of three treatments (alkaline, acid, saline) to spent coffee extracts. Around 2-fold higher content of total phenolics has been estimated in comparison to free compounds. Phenolic compounds with one or more caffeic acid molecules were approximately 54% linked to macromolecules such as melanoidins, mainly by noncovalent interactions (up to 81% of bound phenolic compounds). The rest of the quantitated phenolic acids were mainly attached to other structures by covalent bonds (62-97% of total bound compounds). Alkaline hydrolysis and saline treatment were suitable to estimate total bound and ionically bound phenolic acids, respectively, whereas acid hydrolysis is an inadequate method to quantitate coffee phenolic acids.
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http://dx.doi.org/10.1021/acs.jafc.5b01619DOI Listing
May 2015

Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking?

Food Funct 2014 Aug;5(8):1718-26

Plant Products and Human Nutrition Group, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, UK.

The effect of roasting of coffee beans and the extraction of ground coffee with different volumes of hot pressurised water on the caffeine and the total caffeoylquinic acids (CQAs) content of the resultant beverages was investigated. While caffeine was stable higher roasting temperatures resulted in a loss of CQAs so that the caffeine/CQA ratio was a good marker of the degree of roasting. The caffeine and CQA content and volume was determined for 104 espresso coffees obtained from coffee shops in Scotland, Italy and Spain, limited numbers of cappuccino coffees from commercial outlets and several instant coffees. The caffeine content ranged from 48-317 mg per serving and CQAs from 6-188 mg. It is evident that the ingestion of 200 mg of caffeine per day can be readily and unwittingly exceeded by regular coffee drinkers. This is the upper limit of caffeine intake from all sources recommended by US and UK health agencies for pregnant women. In view of the variable volume of serving sizes, it is also clear that the term "one cup of coffee" is not a reproducible measurement for consumption, yet it is the prevailing unit used in epidemiology to assess coffee consumption and to link the potential effects of the beverage and its components on the outcome of diseases. More accurate measurement of the intake of coffee and its potentially bioactive components are required if epidemiological studies are to produce more reliable information.
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http://dx.doi.org/10.1039/c4fo00290cDOI Listing
August 2014

Antioxidant and genoprotective effects of spent coffee extracts in human cells.

Food Chem Toxicol 2013 Oct 12;60:397-403. Epub 2013 Aug 12.

Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, E-31008 Pamplona, Spain.

Spent coffee has been shown as a good source of hydrophilic antioxidant compounds. The ability of two spent coffee extracts rich in caffeoylquinic acids, mainly dicaffeoylquinic acids, and caffeine (Arabica filter and Robusta espresso) to protect against oxidation and DNA damage in human cells (HeLa) was evaluated at short (2 h) and long (24 h) exposure times. Cell viability (MTT) was not affected by spent coffee extracts (>80%) up to 1000 μg/mL after 2 h. Both spent coffee extracts significantly reduced the increase of ROS level and DNA strand breaks (29-73% protection by comet assay) induced by H₂O₂. Pretreatment of cells with robusta spent coffee extract also decreased Ro photosensitizer-induced oxidative DNA damage after 24 h exposure. The higher effectiveness of Robusta spent coffee extract, with less caffeoylquinic acids and melanoidins, might be due to other antioxidant compounds, such as caffeine and other Maillard reaction products. This work evidences the potential antioxidant and genoprotective properties of spent coffee in human cells.
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http://dx.doi.org/10.1016/j.fct.2013.08.002DOI Listing
October 2013

Catabolism of coffee chlorogenic acids by human colonic microbiota.

Biofactors 2013 Nov-Dec;39(6):623-32. Epub 2013 Aug 1.

Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, Pamplona, Spain.

Several studies have indicated potential health benefits associated with coffee consumption. These benefits might be ascribed in part to the chlorogenic acids (CGAs), the main (poly)phenols in coffee. The impact of these dietary (poly)phenols on health depends on their bioavailability. As they pass along the gastrointestinal tract, CGAs are metabolized extensively and it is their metabolites rather than the parent compounds that predominate in the circulatory system. This article reports on a study in which after incubation of espresso coffee with human fecal samples, high-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS) were used to monitor CGA breakdown and identify and quantify the catabolites produced by the colonic microflora. The CGAs were rapidly degraded by the colonic microflora and over the 6-h incubation period, 11 catabolites were identified and quantified. The appearance of the initial degradation products, caffeic and ferulic acids, was transient, with maximum quantities at 1 h. Dihydrocaffeic acid, dihydroferulic acid, and 3-(3'-hydroxyphenyl)propionic acid were the major end products, comprising 75-83% of the total catabolites, whereas the remaining 17-25% consisted of six minor catabolites. The rate and extent of the degradation showed a clear influence of the composition of the gut microbiota of individual volunteers. Pathways involved in colonic catabolism of CGAs are proposed and comparison with studies on the bioavailability of coffee CGAs ingested by humans helped distinguish between colonic catabolites and phase II metabolites of CGAs.
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http://dx.doi.org/10.1002/biof.1124DOI Listing
July 2014

Evaluation of spent coffee obtained from the most common coffeemakers as a source of hydrophilic bioactive compounds.

J Agric Food Chem 2012 Dec 13;60(51):12565-73. Epub 2012 Dec 13.

Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra , E-31008 Pamplona, Spain.

The main hydrophilic antioxidant compounds (3-, 4-, and 5-monocaffeoylquinic and 3,4-, 3,5-, and 4,5-dicaffeoylquinic acids, caffeine, and browned compounds, including melanoidins) and the antioxidant capacity (Folin-Ciocalteu, ABTS, DPPH, Fremy's salt, and TEMPO) were evaluated in Arabica and Robusta spent coffee obtained from the preparation of coffee brews with the most common coffeemakers (filter, espresso, plunger, and mocha). All spent coffee grounds, with the exception of those from the mocha coffeemaker, had relevant amounts of total caffeoylquinic acids (6.22-13.24 mg/g of spent coffee), mainly dicaffeoylquinic acids (3.31-5.79 mg/g of spent coffee), which were 4-7-fold higher than in their respective coffee brews. Caffeine ranged from 3.59 to 8.09 mg/g of spent coffee. The antioxidant capacities of the aqueous spent coffee extracts were 46.0-102.3% (filter), 59.2-85.6% (espresso), and <42% (plunger) in comparison to their respective coffee brews. This study obtained spent coffee extracts with antioxidant properties that can be used as a good source of hydrophilic bioactive compounds.
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http://dx.doi.org/10.1021/jf3040594DOI Listing
December 2012

Discovery and biochemical characterization of Plasmodium thioredoxin reductase inhibitors from an antimalarial set.

Biochemistry 2012 Jun 1;51(23):4764-71. Epub 2012 Jun 1.

GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire, UK.

Plasmodium falciparum is the most prevalent and deadly species of the human malaria parasites, and thioredoxin reductase (TrxR) is an enzyme involved in the redox response to oxidative stress. Essential for P. falciparum survival, the enzyme has been highlighted as a promising target for novel antimalarial drugs. Here we report the discovery and characterization of seven molecules from an antimalarial set of 13533 compounds through single-target TrxR biochemical screens. We have produced high-purity, full-length, recombinant native enzyme from four Plasmodium species, and thioredoxin substrates from P. falciparum and Rattus norvegicus. The enzymes were screened using a unique, high-throughput, in vitro native substrate assay, and we have observed selectivity between the Plasmodium species and the mammalian form of the enzyme. This has indicated differences in their biomolecular profiles and has provided valuable insights into the biochemical mechanisms of action of compounds with proven antimalarial activity.
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http://dx.doi.org/10.1021/bi3005076DOI Listing
June 2012

Influence of brewing method and acidity regulators on the antioxidant capacity of coffee brews.

J Agric Food Chem 2010 Mar;58(5):2958-65

Department of Nutrition, Food Science, Physiology, and Toxicology, School of Pharmacy (CIFA), University of Navarra, E-31080 Pamplona, Spain.

The antioxidant capacity of coffee brews prepared with different coffeemakers (filter, plunger, mocha, and espresso) was measured by colorimetric (total phenolic compounds and ABTS) and electron spin resonance (ESR) spectroscopy techniques (Fremy's salt and TEMPO). The mocha coffeemaker had the highest yield in coffee antioxidant extraction per gram of ground roasted coffee, but espresso coffee was richest in terms of antioxidant intake (per milliliter of coffee brew) followed by mocha, plunger, and filter. Both Folin-Ciocalteu (total phenolic compounds) and ABTS assays reacted with standard solutions of chlorogenic acids (CGA) and melanoidins (MO-Ala and MO-Gly). However, Fremy's salt was mainly scavenged by chlorogenic acids, whereas the stabilized radical TEMPO was effectively scavenged by melanoidins, but not by chlorogenic acids. Thus, ESR spectroscopy allows distinguishing between phenolic and nonphenolic antioxidants. Moreover, the addition of pH-regulator agents to coffee, such as sodium carbonate (75 ppm) and bicarbonate (75 ppm), to extend its shelf life, slightly increases the pH, modifying the antioxidant capacity in those coffee brews with the highest capacity (mocha and espresso).
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http://dx.doi.org/10.1021/jf9037375DOI Listing
March 2010

Application of multivariate analysis to the effects of additives on chemical and sensory quality of stored coffee brew.

J Agric Food Chem 2008 Dec;56(24):11845-53

Department of Nutrition, Food Science, Physiology, and Toxicology, School of Pharmacy, University of Navarra, E-31080-Pamplona, Spain.

The aim of this work was to obtain a black coffee brew to be consumed hot by extension of its shelf life, by addition of additives. Four pH-regulator agents (sodium and potassium carbonates and bicarbonates), one pH regulator and antioxidant (sodium citrate), three antioxidants [sodium ascorbate, ethylenediaminetetracetic acid (EDTA), and sodium sulfite], and lactoserum were tested by sensory analysis. Sodium carbonate and bicarbonate were selected for a study of the physicochemical (soluble and volatile compounds related to the sensory properties) and sensorial quality of coffee brew stored for 90 days at 4 degrees C. Although both additives extended the shelf life of the coffee brew up to 60 days, sodium carbonate was the chosen additive because it was the most useful in limiting the pH decrease and perception of sourness, which are some of the main factors involved in the rejection of stored coffee brews, and it better maintained the aroma and taste/flavor. Moreover, the application of multivariate analysis facilitated first the description of the global changes of the coffee brews with or without additives throughout the storage using principal component analysis and second the obtainment of a simple equation only with pH and caffeic acid parameters to discriminate the three types of coffee brews and simplify the analytical process, by means of the stepwise discriminant analysis.
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http://dx.doi.org/10.1021/jf802146vDOI Listing
December 2008

Changes in volatile compounds and overall aroma profile during storage of coffee brews at 4 and 25 degrees C.

J Agric Food Chem 2008 May 19;56(9):3145-54. Epub 2008 Apr 19.

Department of Nutrition, Food Science, Physiology and Toxicology, School of Pharmacy, University of Navarra, E-31080 Pamplona, Spain.

In this work, the chemical changes occurring in the volatile fraction of Arabica coffee brews during storage at 4 and 25 degrees C for 30 days have been characterized for the first time by means of HS-GC-MS. A total of 47 compounds were identified and quantified: 2 sulfur compounds, 7 aldehydes, 3 esters, 15 furans, 5 ketones, 1 alcohol, 2 thiophenes, 4 pyrroles, 1 pyridine, 5 pyrazines, 1 alkene, and 1 acid. No new volatile compounds were detected at the end of the storage time. The changes observed are, in general, slower and less pronounced at refrigeration temperature. Storage also affects the sensory characteristics of the stored coffee brews, which lose part of their aroma intensity and freshness, acquiring some nondesirable notes such as rancid aroma, mainly during storage at 25 degrees C. Furthermore, seven aroma indices have been proposed as indicators of coffee brew staling, which show a good correlation with some sensory attributes, not only for aroma but also overall sensory quality. Consequently, they could be considered useful to monitor both the "age" and the sensory quality of stored coffee brews.
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http://dx.doi.org/10.1021/jf703731xDOI Listing
May 2008

Correlation of selected constituents with the total antioxidant capacity of coffee beverages: influence of the brewing procedure.

J Agric Food Chem 2007 Jul 4;55(15):6110-7. Epub 2007 Jul 4.

Department of Nutrition and Food Science, Physiology and Toxicology, School of Pharmacy, University of Navarra, E-31008 Pamplona, Spain.

Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines.
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http://dx.doi.org/10.1021/jf070779xDOI Listing
July 2007

Changes in headspace volatile concentrations of coffee brews caused by the roasting process and the brewing procedure.

J Agric Food Chem 2006 Nov;54(22):8560-6

Department of Food Science and Technology, and Toxicology, School of Pharmacy, University of Navarra, E-31080 Pamplona, Spain.

Headspace-solid-phase microextraction technique (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used to characterize the aroma compounds of coffee brews from commercial conventional and torrefacto roasted coffee prepared by filter coffeemaker and espresso machine. A total of 47 volatile compounds were identified and quantified. Principal component analysis (PCA) was applied to differentiate coffee brew samples by volatile compounds. Conventional and torrefacto roasted coffee brews were separated successfully by principal component 1 (68.5% of variance), and filter and espresso ones were separated by principal component 2 (19.5% of variance). By GC olfactometry, a total of 34 aroma compounds have been perceived at least in half of the coffee extracts and among them 28 were identified, among which octanal was identified for the first time as a contributor to coffee brew aroma.
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http://dx.doi.org/10.1021/jf061178tDOI Listing
November 2006

Chemical and sensorial characteristics of espresso coffee as affected by grinding and torrefacto roast.

J Agric Food Chem 2003 Nov;51(24):7034-9

Departamento de Bromatología, Tecnología de Alimentos y Toxicología, Facultad de Farmacia, Universidad de Navarra, E-31080 Pamplona, Spain.

Grinding is a critical step in the preparation of espresso coffee (EC). The addition of sugar during the torrefacto roasting process could influence the degree of brittleness and grinding. The aim of this work was to study the influence of the grinding grades (coarse, fine, and very fine) in Arabica/Robusta 20:80, natural roasted (A20:R80), and Arabica/Robusta 20:80 with 50% Robusta torrefacto roasted (A20:R80 50% torrefacto) on the chemical and sensorial characteristics of EC in order to select the optimal espresso grinding grade. A higher percentage of coarse particles was found in A20:R80 ground coffee. In both ECs, the extraction of solids and soluble and aroma compounds increased inversely with particle size. Higher foam indices and extraction yields were found in A20:R80 50% torrefacto ECs probably due to the solubilization of caramelized sugar and melanoidins. It has been suggested that the range of an acceptable extraction yield could be extended to 25% in A20:R80 50% torrefacto ECs. In conclusion, the optimal grinding grade for the obtainment of an EC with A20:R80 was fine and that for A20:R80 50% torrefacto was coarse.
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http://dx.doi.org/10.1021/jf034628fDOI Listing
November 2003