Iziar A. Ludwig

Iziar A. Ludwig
Universidad de Navarra | UNAV · Department of Nutrition, Food Science and Physiology

PhD

About

74
Publications
28,625
Reads
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2,517
Citations
Citations since 2016
63 Research Items
2421 Citations
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
20162017201820192020202120220100200300400500
Additional affiliations
July 2013 - August 2014
University of Glasgow
Position
  • Research Associate
April 2009 - June 2013
Universidad de Navarra
Position
  • PhD Student

Publications

Publications (74)
Article
The present study aimed to evaluate the metabolism and bioavailability of anthocyanins (ACN) and other phenolics from red-fleshed apple (RFA) and to define the intake biomarkers compared to common white-fleshed apple (WFA). Acute and sustained (6-week) interventions were combined in a randomized, controlled and parallel study with 121 hypercholeste...
Article
Red-fleshed apple cultivars with an enhanced content of anthocyanins have recently attracted the interest of apple producers and consumers due to their attractive color and promising added health benefits. In this paper, we provide the first comprehensive overview of new hybrid red-fleshed apples, mainly focusing on their (poly)phenolic composition...
Article
It has been established that ageing is the major risk factor for cognitive deficiency and it is becoming increasingly evident that insulin resistance is another factor. Biological plausibility for a link between insulin resistance and dementia is relevant for understanding disease etiology, and to form bases for prevention efforts to decrease disea...
Article
Artichokes are an important source of (poly)phenolic compounds, mainly caffeoylquinic acids, which consumption has been associated with health benefits. However, heat treatments have shown to affect the amounts of these bioactive food compounds. In the present study the influence of culinary techniques (boiling, griddling, and frying) on the total...
Article
Artichokes are a rich source of (poly)phenols, mainly caffeoylquinic acids, but little is known about their bioavailability from this source. This study investigated the absorption, metabolism and excretion of (poly)phenols after sous-vide artichoke consumption (5776 µmol of (poly)phenols) by healthy volunteers. Seventy-six (poly)phenol metabolites...
Article
The present study aimed to investigate the metabolic fate and the cardiometabolic effects of phenolic compounds (PC) provided by a red‐fleshed apple variety biofortified in anthocyanins (ACN). Wistar rats were feed with high‐fat diet (HFD) to induce hypercholesterolemia and supplemented with red‐fleshed apple (HFD+R), white‐fleshed apple (HFD+W) or...
Article
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 human colonic fermentation. A total of 28 (poly)phenolic compounds were identified and quantified by LC-MS/MS in raw, boiled, sous vide and microwaved Tude...
Article
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 metaboli...
Chapter
Hydroxycinnamates are ubiquitous in the plant kingdom as free phenolic acids or esterified to organic acids, polysaccharides or lipids, and thus, are present in all plant food groups, with mayor dietary sources being coffee and cereal‐based products. After ingestion, hydroxycinnamates are subjected to different reactions in the upper and lower gast...
Article
Full-text available
The present study evaluated the impact of different thermal (infrared-drying, hot air-drying and purée pasteurization) and non-thermal (freeze-drying) processing technologies on red-fleshed apple (poly)phenolic compounds. We further investigated the processing effect on the (poly)phenol bioavailability in a crossover postprandial study where three...
Article
The health benefits of orange juice (OJ) consumption are attributed in part to the circulating flavanone phase II metabolites and their microbial-derived ring fission phenolic catabolites. The present study investigated these compounds in the bloodstream after acute intake of 500 mL of OJ. Plasma samples obtained at 0, 1, 2, 3, 4, 5, 6, 7, 8 and 24...
Article
The analysis of the fat-soluble vitamins A and E and lipid micronutrients in blood, such as carotenoids, is an important parameter to monitor the micronutrient status in humans. Although the potential of dried blood spot (DBS) cards, the use of this technique for blood sampling and subsequent analysis of these fat-soluble micronutrients has been po...
Article
Full-text available
Hypertension is an independent and preventable risk factor for the development of cardiovascular diseases, however, little is known about the impact of gut microbiota composition in its development. We carried out comprehensive gut microbiota analysis and targeted metabolomics in a cross-sectional study of 29 non-treated hypertensive (HT) and 32 no...
Chapter
The chemistry of purine, pyrimidine, and pyridine nucleobases, nucleosides, and nucleotides constitute one of the oldest topics in biochemistry. This chapter describes the nomenclature and abbreviations of nucleotide‐related compounds and major chemical structures of purines, pyrimidine, and pyridine. Pyridine is a basic heterocyclic organic compou...
Chapter
This chapter describes the occurrence and biosynthesis of trigonelline and related nicotinate metabolites. Trigonelline is synthesized from nicotinate which is a catabolite of pyridine nucleotides. The biosynthesis of trigonelline is, therefore, analogous to that of caffeine, which is derived from purine nucleotides. Although nicotinate utilized fo...
Chapter
Full-text available
Purines and pyrimidines are major chemical constituents of cells and occur primarily as components of DNA and RNA (polymerized nucleotides), and to a much lesser extent in the form of ‘free’ (aka ‘soluble’) nucleotides. Compared with nucleotides, free nucleosides and bases usually represent a very small fraction of the total purine and pyrimidine c...
Chapter
Full-text available
The catabolism of pyrimidine nucleotides, like that of purine nucleotides, involves dephosphorylation, deamination, and glycosidic bond cleavage. However, in contrast to purine catabolism, the pyrimidine bases in most organisms are subjected to reduction rather than oxidation. Reductive pyrimidine base catabolism occurs in most microorganisms, plan...
Chapter
Full-text available
This chapter discusses the involvement of purine and pyrimidine nucleotides in response to different types of stress. Environmental factors that affect plant growth include light, temperature, water, humidity, and nutrition. Cultured plant cells have in the main been utilized for detailed investigations on the metabolic role of nutrients. Inorganic...
Article
All organisms produce nucleobases, nucleosides and nucleotides of purines, pyrimidines and pyridines. There have been a number of books on nucleotide metabolism in microorganisms and humans. However, this is the first to focus on plants which exhibit important differences to other organisms in key areas of nucleotide metabolism and function. The bo...
Chapter
Full-text available
This chapter presents the enzymes involved in purine nucleotide biosynthesis in plants. The end products of purine catabolism in various animals differ from those found in plants. Xanthine is the starting material of purine degradation and end products in plants are ammonia, carbon dioxide, and glyoxylate. In some plant species, there is a transien...
Chapter
The de novo pyrimidine biosynthetic pathway, the synthesis of uridine‐5'‐monophosphate (UMP) from carbamoyl‐phosphate, is evolutionarily conserved from prokaryotes to eukaryotes. The pathway consists of the synthesis of carbamoyl‐aspartate, formation of orotate, and the production of UMP. In higher eukaryotes, including plants, orotate phosphoribos...
Chapter
The pathway of caffeine biosynthesis from xanthosine, a catabolite of purine nucleotides, has been elucidated in both coffee and tea. In the 1970s research on caffeine biosynthesis was carried out using intact plant tissues and tissue cultures. These studies confirmed that the purine ring of caffeine was produced from the same precursors that were...
Chapter
In plants the pyrimidine base uracil, some pyrimidine ribonucleosides and pyrimidine deoxyribonucleosides can be utilized for the generation of their respective nucleoside‐5'‐monophosphates which are then phosphorylated producing pyrimidine nucleoside‐triphosphates. Profiles of in vitro activity of enzymes involved in pyrimidine salvage have been d...
Chapter
Four purine skeletons, namely, adenine, guanine, hypoxanthine, and xanthine occur as bases, nucleosides, and nucleotides. There is diversity in the deamination reactions in different species as they can occur at the nucleotide, nucleoside, or nucleobase levels. Dephosphorylation of purine nucleotides in plant extracts is catalysed by various enzyme...
Chapter
Nucleotide sugars are monosaccharides that have a nucleotide, usually uridine triphosphate (UTP), bound to the carbohydrate chain through an energy rich linkage. UTP is synthesized by the de novo pyrimidine biosynthesis. Sugar nucleotides are essential building blocks for metabolism of all living organisms. In plant sugar metabolism, sugar nucleoti...
Chapter
This chapter summarizes physiological and ecological aspects of caffeine production. There are many physiological‐based publications related to organs and tissue age, cellular and subcellular location, and control mechanisms of caffeine biosynthesis. Theobromine synthesis from purine nucleotides via xanthosine appears to be restricted to young tiss...
Chapter
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are coenzymes found in all living cells. It consists of two nucleotides, namely adenine nucleotide and a pyridine nucleotide joined through their phosphate groups. Many nucleotide reviews have described only purine and pyrimidine nucleotides without menti...
Chapter
This chapter reviews information on the enzymes involved in the pyrimidine conversions, namely, deaminases, nucleosidases, and phosphorylases. A diversity of pyrimidine interconversions occur in different organisms. In bacteria, such as E. coli, Saccharomyces cerevisiae, and Klebsiella pneumoniae, cytosine deaminase is an enzyme in the pyrimidine i...
Chapter
This chapter discusses the metabolism of purine alkaloids, including biotechnology‐based studies on caffeine. In contrast to the slow metabolism of caffeine in C. arabica leaves, theophylline is catabolized very rapidly. In kucha, caffeine was metabolized to theacrine by expanding buds, and young and mature leaves; the conversion to methyluric acid...
Chapter
Full-text available
The de novo biosynthesis of purine nucleotides was elucidated independently by J. M. Buchanan and Greenberg in the 1950s. Substantial amounts of ureides are produced as the major nitrogen‐containing compounds derived from purine nucleotides. This chapter describes the reaction and enzymes of de novo purine nucleotide biosynthesis. There are 10 step...
Chapter
The concentration of caffeine in green coffee beans varies between 0.9‐1.3 and 1.5‐2.5% dry matter for arabica and robusta coffees, respectively. The caffeine content of beans is not markedly reduced by roasting, although losses, presumably due to sublimation, may occur if the heating process is carried out at higher temperatures. Caffeine consumpt...
Chapter
Full-text available
Cytokinins along with gibberellins, auxins, abscisic acid, and brassinosteroids are major classes of plant hormones. Among these naturally occurring phytohormones, cytokinins are unique in that they have an adenine‐type structure. Cytokinin biosynthesis, interconversions and degradation are involved in the regulation of cytokinin homeostasis during...
Chapter
Full-text available
The most well‐known secondary metabolites synthesized from nucleotides are purine alkaloids. Purine alkaloids, namely methylxanthines and methylurates, occur in a variety of plant species. The major purine alkaloid typically is caffeine, which is found in popular non‐alcoholic beverages such as coffee, tea, and matĕ. The biosynthetic pathway of caf...
Chapter
A majority of the investigations on nucleotide metabolism during growth and development of plants have been carried out by monitoring the fate of radiolabelled purine and pyrimidine bases and nucleosides, which are readily taken up by tissues. Studies on pyrimidine metabolism conducted with maturing P. glauca somatic embryos demonstrated that the d...
Chapter
This chapter describes the biosynthesis of trigonelline, and its various roles in plants, and plant biotechnology. Changes in trigonelline biosynthesis occur during the growth of leaves and fruits of coffee plants. Several in planta roles for trigonelline have been proposed, namely: as a nutrient source, a compatible solute, a bioactive substance f...
Chapter
This chapter focuses on the formation of purine, pyrimidine, and pyridine ribonucleoside monophosphates from small molecular weight precursors, the initial metabolites of de novo nucleotide biosynthesis. It also focuses on conversion of these initial metabolites to nucleoside di‐ and triphosphates, and synthesis of deoxyribonu‐cleotides from ribonu...
Chapter
Purine and pyrimidine metabolism, in addition to de novo biosynthesis of pyridine nucleotides, a salvage synthesis pathway also occurs. However, the pyridine ring is more efficiently recycled than is the case with degradation of purine and pyrimidine. The pyridine nucleotide cycle, which includes pyridine nucleotide catabolism and regeneration of p...
Chapter
Full-text available
The net formation of purine nucleotides is performed by the de novo pathway, but rapid turnover of nucleic acids, especially RNA, is required for nucleotide production by the salvage pathways. In plant cells, purine bases and nucleosides originate from the intercellular breakdown of nucleic acids and nucleotides, as well as other reactions which re...
Article
Full-text available
Purpose: There is much information on the bioavailability of (poly)phenolic compounds following acute intake of various foods. However, there are only limited data on the effects of repeated and combined exposure to specific (poly)phenol food sources and the inter-individual variability in their bioavailability. This study evaluated the combined u...
Article
Covering: 1958 to June 2018 Phenyl-γ-valerolactones (PVLs) and their related phenylvaleric acids (PVAs) are the main metabolites of flavan-3-ols, the major class of flavonoids in the human diet. Despite their presumed importance, these gut microbiota-derived compounds have, to date, in terms of biological activity, been considered subordinate to th...
Article
The aim of this study was to investigate comprehensively the metabolic pathways and human bioavailability of anthocyanins and other (poly)phenols in an apple matrix, and to elucidate potential intake biomarkers. After the acute intake of a red-fleshed apple freeze-dried snack, plasma and urine were collected and analyzed by UPLC-MS/MS. A total of 3...
Article
Full-text available
Gut microbiota has been suggested to affect lipid metabolism. The objective of this study was to characterize the faecal microbiota signature and both short chain fatty acids (SCFAs) and bile acids (BA) profile of hypercholesterolemic subjects. Microbiota composition, SCFAs, BA and blood lipid profile from male volunteers with hypercholesterolemia...
Chapter
Coffee is one of the most consumed beverages in the world, and its consumption increases every year. The quality of a cup of coffee depends on many factors related to coffee, water and the coffeemaker. Coffee species, variety and origin have a clear influence on the chemical composition and quality of coffee brew, but many other factors from harves...
Article
Scope The application of dried blood spot (DBS) cards for the study in human blood of dietary polyphenol bioavailability has been poorly studied. Methods and results An analytical method based on blood sampling with DBS cards combined with liquid chromatography coupled to tandem mass spectrometry has been developed and validated. To test the metho...
Article
The present study compared and validated two analytical methods, HPLC-HRMS, and GC-MS using MSTFA as derivatization agent, for the analysis of microbiota-derived phenolic acids and aromatic compounds accumulating in urine, collected over a 24 h period after the consumption of 500 mL of orange juice. In addition, purification procedures using SDB-L...
Article
Among cereals, barley (Hordeum vulgare L.) is notable for its high content of bioactives such as β-glucan and phenolic compounds, but it is not used as widely in human nutrition as wheat. To compare the impact of food formulation and processing on barley bioactives, crackers, cookies and fresh pasta were prepared combining wheat and barley flour. A...
Article
This study developed, optimized and validated an ultra-high-performance liquid chromatography–high-resolution mass spectrometry (UHPLC-HRMS) method to identify and quantify metabolites and microbial-derived catabolites in urine, plasma and feces of rats following ingestion of 50 mg of a red wine proanthocyanidin-rich extract. The method was validat...
Article
Full-text available
PurposeOrange juice (OJ) flavanones undergo limited absorption in the upper gastrointestinal tract and reach the colon where they are transformed by the microbiota prior to absorption. This study investigated the ability of two probiotic bacteria, Bifidobacterium longum R0175 and Lactobacillus rhamnosus subsp. Rhamnosus NCTC 10302 to catabolise OJ...
Chapter
(Poly)phenols, secondary plant products, have been linked with numerous health benefits associated with vegetable- and fruit-rich diets. Once ingested, (poly)phenols suffer extensive transformations during their passage through the gastrointestinal tract and it is their metabolites rather than the parent compounds present in food that might exert h...
Article
Full-text available
Covering: 2000 up to late 2017 This review is focussed upon the acyl-quinic acids, the most studied group within the ca. 400 chlorogenic acids so far reported. The acyl-quinic acids, the first of which was characterised in 1846, are a diverse group of plant-derived compounds produced principally through esterification of an hydroxycinnamic acid and...
Article
Full-text available
Background: Physical exercise has been reported to increase the bioavailability of citrus flavanones.Objective: We investigated the bioavailability of orange juice (OJ) (poly)phenols in endurance-trained males before and after cessation of training for 7 d.Design: Ten fit, endurance-trained males, with a mean ± SD maximal oxygen consumption of 58.2...
Article
A total of 17 (poly)phenolic compounds have been quantified in the free and bound fraction of raw, olive oil fried, sunflower oil fried and griddled cardoon (Cynara cardunculus L.). Caffeoylquinic acid derivatives (CQAs), particularly 5-CQA, were the major compounds. The bioaccessibility of (poly)phenols after gastrointestinal digestion and fecal f...
Article
This review considers recent investigations on the bioavailability of anthocyanins and flavanones. Both flavonoids are significant dietary components and are considered to be poorly bioavailable, as only low levels of phase II metabolites appear in the circulatory system and are excreted in urine. However, when lower molecular weight phenolic and a...
Article
SCOPE: Previous studies have proposed that phytosterols activate liver X receptors (LXR) in the intestine, thereby reducing intestinal cholesterol absorption and promoting fecal cholesterol excretion. METHODS AND RESULTS: In the present study, we examined the effects of dietary phytosterol supplementation on intestinal cholesterol absorption and fe...
Article
A total of 21 (poly)phenolic compounds (free and bound) were quantified in raw, olive oil fried, sunflower oil fried and griddled green pepper before and after a simulated gastrointestinal digestion. Flavonoids, particularly quercetin rhamnoside, were the main compounds. The bioaccessibility of (poly)phenolic compounds after gastrointestinal digest...
Article
Beneficial properties attributed to the intake of fruit and red wine have been associated with the presence of significant amounts of anthocyanins. However, their low absorption and consequent accumulation in the gut have generated the suspicion that colonic metabolites of anthocyanins are probably involved in their protective effects. Grape pomace...
Article
Orange juice is a rich source of (poly)phenols, in particular the flavanones hesperetin-7-O-rutinoside and naringenin-7-O-rutinoside. Following the acute consumption of 500 mL of orange juice containing 398 µmol of (poly)phenols by 12 volunteers, 0-24 h plasma and urine samples were analysed by targeted high-performance liquid chromatography-high r...
Article
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...
Article
Full-text available
Red raspberries, containing ellagitannins and cyanidin-based anthocyanins, were fed to volunteers and metabolites appearing in plasma and urine were analysed by UHPLC-MS. Anthocyanins were not absorbed to any extent with sub nmol/L concentrations of cyanidin-3-O-glucoside and a cyanidin-O-glucuronide appearing transiently in plasma. Anthocyanins ex...
Article
Full-text available
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. Durin...
Article
Full-text available
Spent coffee is the main by-product 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,...
Article
Full-text available
This review describes the occurrence and biosynthesis of trigonelline (N- methylnicotinic acid) and related nicotinic acid metabolites. High concentrations of trigonelline are found in seeds of coffee, and some members of the Fabaceae, while trace amounts occur in many other species. In contrast, the occurrence of other pyridine alkaloids derive...
Article
Full-text available
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...
Article
Heterocyclic volatile compounds present in coffee have been proposed as potent antioxidants, but their contribution to the antioxidant capacity of coffee is still unclear and controversial. The aim of this study was to assess the actual contribution of the main volatile compounds to the overall antioxidant capacity of coffee. A total of sixty-two a...
Article
This review provides details on the phytochemicals in green coffee beans and the changes that occur during roasting. Key compounds in the coffee beverage, produced from the ground, roasted beans, are volatile constituents responsible for the unique aroma, the alkaloids caffeine and trigonelline, chlorogenic acids, the diterpenes cafestol and kahweo...
Article
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 metabol...
Article
The addition of sugar during roasting (torrefacto) has been proposed as a technique to increase the antioxidant capacity. However, other factors such as roasting degree and coffee origin also play a key role. Two batches of Colombian green coffee were roasted adding increased amounts of sucrose (0–15 g per 100 g of coffee) to reach the same roastin...
Article
The aim of this work was to study the extraction behavior of the main coffee antioxidants (caffeoylquinic acids, melanoidins and caffeine) and the antioxidant capacity, during brewing time in the most widely consumed coffee brew methods (filter and espresso) in coffee. Antioxidant capacity by colorimetric assays (Folin–Ciocalteau, ABTS and DPPH) an...

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