Identification of novel circulating coffee metabolites in human plasma by liquid chromatography–mass spectrometry

Implementation of multiomic mass spectrometry approaches for the evaluation of human health following environmental exposure

Omics analyses collectively refer to the possibility of profiling genetic variants, RNA, epigenetic markers, proteins, lipids, and metabolites. The most common analytical approaches used for detecting molecules present within biofluids related to metabolism are vibrational spectroscopy techniques, represented by infrared, Raman, and nuclear magnetic resonance (NMR) spectroscopies and mass spectrometry (MS). Omics-based assessments utilizing MS are rapidly expanding and being applied to various scientific disciplines and clinical settings. Most of the omics instruments are operated by specialists in dedicated laboratories; however, the development of miniature portable omics has made the technology more available to users for field applications. Variations in molecular information gained from omics approaches are useful for evaluating human health following environmental exposure and the development and progression of numerous diseases. As MS technology develops so do statistical and machine learning methods for the detection of molecular deviations from personalized metabolism, which are correlated to altered health conditions, and they are intended to provide a multi-disciplinary overview for researchers interested in adding multiomic analysis to their current efforts. This includes an introduction to mass spectrometry-based omics technologies, current state-of-the-art capabilities and their respective strengths and limitations for surveying molecular information. Furthermore, we describe how knowledge gained from these assessments can be applied to personalized medicine and diagnostic strategies.

Comparative bioactivity evaluation and metabolic profiling of different parts of Duhaldea nervosa based on GC-MS and LC-MS

Duhaldea nervosa (Wallich ex Candolle) Anderberg has been widely used as medicine and food additive in China for a long history. Its roots, known as Xiaoheiyao, are the mainly used medicinal part, while the other tissues of D. nervosa are ignored as non-medicinal parts despite their high biomass, resulting in a huge waste of resources. To mine and expand the medicinal values of different parts of D. nervosa, metabolic analysis by GC/LC-MS and bioactivity evaluation were performed. Based on the antioxidant activity and correlation analysis, a metabolite-related network was constructed. A total of 45 volatile and 174 non-volatile compounds were identified. Among them, caffeoylquinic acids and derivatives were more abundant in roots and flowers, while coumaroyltartaric acids and derivatives were mainly present in stems and leaves. By multivariate analysis, 13 volatile and 37 non-volatile differential metabolites were found, respectively. In the bioactivity evaluation of different parts, the order of antioxidant capacity was flowers > roots > leaves or stems. The flowers showed the highest FRAP value (354.47 μM TE/g DW) and the lowest IC50 values in the DPPH (0.06 mg/mL) and ABTS (0.19 mg/mL) assay, while higher inhibitory activity against α-glucosidase was exhibited by flowers and leaves. This study first established the similarities and differences of phytochemicals and bioactivities in D. nervosa, providing a scientific basis for developing non-medicinal parts and guiding the clinical application of this medicinal and edible herb.

3-(4-Hydroxy-3-methoxyphenyl) propionic acid contributes to improved hepatic lipid metabolism via GPR41

3-(4-hydroxy-3-methoxyphenyl) propionic acid (HMPA) is a metabolite produced by the gut microbiota through the conversion of 4-hydroxy-3-methoxycinnamic acid (HMCA), which is a widely distributed hydroxycinnamic acid-derived metabolite found abundantly in plants. Several beneficial effects of HMPA have been suggested, such as antidiabetic properties, anticancer activities, and cognitive function improvement, in animal models and human studies. However, the intricate molecular mechanisms underlying the bioaccessibility and bioavailability profile following HMPA intake and the substantial modulation of metabolic homeostasis by HMPA require further elucidation. In this study, we effectively identified and characterized HMPA-specific GPR41 receptor, with greater affinity than HMCA. The activation of this receptor plays a crucial role in the anti-obesity effects and improvement of hepatic steatosis by stimulating the lipid catabolism pathway. For the improvement of metabolic disorders, our results provide insights into the development of functional foods, including HMPA, and preventive pharmaceuticals targeting GPR41.

Assessment of human inter-individual variability of phloretin metabolites in urine after apple consumption. AppleCOR study

Purpose: This study aimed to assess the inter-individual variation in phloretin absorption and metabolism and to seek possible phloretin metabotypes following apple snack consumption. Methods: The excreted phloretin metabolites in 24 h urine samples were determined by UPLC-MS/MS in 62 volunteers after acute and sustained (6 weeks) interventions in a randomized and parallel study with a daily supplementation of 80 g of a low-phloretin (39.5 μmol) or a high-phloretin (103 μmol) freeze-dried apple snacks. Results: absorption estimated as phloridzin equivalents for 62 volunteers varied almost 70-fold ranging from 0.1% to 6.94% of phloretin glycoside intake. Volunteers were stratified into low, medium and high producers and by the balance between glucuronidation and sulphation. For 74% of the volunteers phloretin-O-glucuronide was the dominant urinary metabolite, especially at the higher phloretin glycoside intake and for higher producers. Sulphate conjugation assumed greater significance for the remaining volunteers especially for low producers. Females dominated glucuronide profile (64.1%) and males dominated the low excretion group. Analysis of plasma glucose and insulin at the start and end of the sustained study showed a trend towards modest reductions for high producers. Furthermore, plausible factors contributing to the inter-individual variation in phloretin uptake are discussed. Conclusions: extensive inter-individual variability exists in the excretion of phloretin phase-II conjugates following consumption of apple snacks, which could be related to oral microbiota phloridzin-hydrolysing activity, lactase non-persistence trait or the metabotype to which the subject belongs. There were inconsistent effects on post-prandial serum glucose concentrations but there was a tendency for decreases to be associated with higher excretion of phloretin phase-II conjugates. Trial registration: The acute and sustained studies were registered at ClinicalTrials.gov Identifier: NCT03795324.

Dihydrocaffeic Acid-Is It the Less Known but Equally Valuable Phenolic Acid?

Dihydrocaffeic acid (DHCA) is a phenolic acid bearing a catechol ring and three-carbon side chain. Despite its being found in minor amounts in numerous plants and fungi of different origins, it has attracted the interest of various research groups in many fields of science, from food to biomedical applications. The review article presented herein aims to show a wider audience the health benefits and therapeutic, industrial, and nutritional potential of dihydrocaffeic acid, by sheddinglight on its occurrence, biosynthesis, bioavailability, and metabolism. The scientific literature describes at least 70 different derivatives of dihydrocaffeic acid, both those occurring naturally and those obtained via chemical and enzymatic methods. Among the most frequently used enzymes that were applied for the modification of the parent DHCA structure, there are lipases that allow for obtaining esters and phenolidips, tyrosinases used for the formation of the catechol ring, and laccases to functionalize this phenolic acid. In many studies, both in vitro and in vivo, the protective effect of DHCA and its derivatives on cells subjected to oxidative stress and inflammation were acknowledged.

Urinary metabolomics of phenolic compounds reveals biomarkers of type-2 diabetes within the PREDIMED trial

BACKGROUND

Phenolic compounds have been associated with protective effects against type-2 diabetes (T2D). We used a metabolomics approach to determine urinary phenolic metabolites associated with T2D and fasting plasma glucose.

METHODS

This case-control study within the PREDIMED trial included 200 participants at high cardiovascular risk, 102 of whom were diagnosed with T2D. A panel of urinary phenolic compounds were analysed using a novel method based on liquid chromatography coupled to mass spectrometry. Multivariate statistics and adjusted logistic regressions were applied to determine the most discriminant compounds and their association with T2D. The relationship between the discriminant phenolic compounds and plasma glucose was assessed using multivariable linear regressions.

RESULTS

A total of 41 phenolic compounds were modeled in the orthogonal projection to latent structures discriminant analysis, and after applying adjusted logistic regressions two were selected as discriminant: dihydrocaffeic acid (OR = 0.22 (CI 95 %: 0.09; 0.52) per 1-SD, p-value = 0.021) and genistein diglucuronide (OR = 0.72 (CI 95%: 0.59; 0.88) per 1-SD, p-value = 0.021). Both metabolites were associated with a lower risk of suffering from T2D, but only dihydrocaffeic acid was inversely associated with plasma glucose (β = -17.12 (95 % CI: -29.92; -4.32) mg/dL per 1-SD, p-value = 0.009).

CONCLUSIONS

A novel method using a metabolomics approach was developed to analyse a panel of urinary phenolic compounds for potential associations with T2D, and two metabolites, dihydrocaffeic acid and genistein diglucuronide, were found to be associated with a lower risk of this condition.

Cytotoxic and chemomodulatory effects of Phyllanthus niruri in MCF-7 and MCF-7ADR breast cancer cells

The members of the genus Phyllanthus have long been used in the treatment of a broad spectrum of diseases. They exhibited antiproliferative activity against various human cancer cell lines. Breast cancer is the most diagnosed cancer and a leading cause of cancer death among women. Doxorubicin (DOX) is an anticancer agent used to treat breast cancer despite its significant cardiotoxicity along with resistance development. Therefore, this study was designed to assess the potential cytotoxicity of P. niruri extracts (and fractions) alone and in combination with DOX against naïve (MCF-7) and doxorubicin-resistant breast cancer cell lines (MCF-7^ADR). The methylene chloride fraction (CH₂Cl₂) showed the most cytotoxic activity among all tested fractions. Interestingly, the CH₂Cl₂-fraction was more cytotoxic against MCF-7^ADR than MCF-7 at 100 µg/mL. At sub-cytotoxic concentrations, this fraction enhanced the cytotoxic effect of DOX against the both cell lines under investigation (IC₅₀ values of 0.054 µg/mL and 0.14 µg/mL vs. 0.2 µg/mL for DOX alone against MCF-7) and (1.2 µg/mL and 0.23 µg/mL vs. 9.9 µg/mL for DOX alone against MCF-7^ADR), respectively. Further, TLC fractionation showed that B2 subfraction in equitoxic combination with DOX exerted a powerful synergism (IC₅₀ values of 0.03 µg/mL vs. 9.9 µg/mL for DOX alone) within MCF-7^ADR. Untargeted metabolite profiling of the crude methanolic extract (MeOH) and CH₂Cl₂ fraction exhibiting potential cytotoxicity was conducted using liquid chromatography diode array detector-quadrupole time-of-flight mass spectrometry (LC-DAD-QTOF). Further studies are needed to separate the active compounds from the CH₂Cl₂ fraction and elucidate their mechanism(s) of action.

LC-MS Characterization and Quantification of Known and Unknown (Poly)phenol Metabolites-Possible Pitfalls and Their Avoidance

This review focuses on the LC-MS characterization and quantification of dietary (poly)phenols and their metabolites. It draws attention to errors, omissions, and misunderstandings that appear frequently in published papers, and suggests strategies for their avoidance. Aspects covered include the use of authentic standards and surrogate reference materials, the importance of collecting and archiving Total Ion Current MS data, the limitations of using on-line compilations of accurate mass MS data to assign unknown components when multiple isomers are possible, and the often understated magnitude of person-to-person variation that may significantly impact at population level any potential health benefit.

Effect of different patterns of consumption of coffee and a cocoa-based product containing coffee on the nutrikinetics and urinary excretion of phenolic compounds

BACKGROUND

Coffee consumption is associated with a reduced risk of several chronic diseases in a dose-dependent manner. Chronic intake results in the transient appearance of bioactive phenolic metabolites in the circulatory system. However, there is a lack of information on the impact of different patterns of coffee consumption on plasma and urinary profiles of phenolic metabolites.

OBJECTIVES

Plasma and urinary phenolic metabolites were investigated following regular consumption of different daily dosages of coffee or cocoa-based products containing coffee (CBPCC) under a real-life setting.

METHODS

A repeated-dose, randomized, crossover human intervention was conducted with 21 healthy volunteers. For 1 mo, participants consumed 1) 1 cup of coffee (1C), 2) 3 cups of coffee (3C), or 3) 1 cup of coffee + 2 CBPCC twice daily (PC). Plasma and urine samples were collected over a 24-h period after each treatment. The nutrikinetics and urinary excretion of native, human phase II, and colonic metabolites were assessed.

RESULTS

A total of 51 (poly)phenolic metabolites were quantified, with 41 metabolites being strictly related to coffee consumption. Significant differences were observed among treatments for most of the metabolites. The metabolites present in the highest amounts were the hydroxycinnamate, phenylpropanoic acid, benzaldehyde, and benzene classes, along with (-)-epicatechin and phenyl-γ-valerolactone derivatives after PC treatment. Daily average concentrations did not exceed 200 nmol/L and were <100 nmol/L for most of the metabolites. The excretion of coffee phenolics ranged from 40% to 70% of intake, indicating that coffee hydroxycinnamates are notably more bioavailable than previously thought. Interindividual variability was also investigated.

CONCLUSIONS

The absorption, metabolism, nutrikinetic profile, and bioavailability of coffee phenolics were established for different patterns of coffee consumption under real-life conditions. This work provides the basis for further nutritional epidemiology research and mode-of-action cell-based studies. This study was registered at clinicaltrials.gov as NCT03166540.

Multiple catechols in human plasma after drinking caffeinated or decaffeinated coffee

BACKGROUND

Coffee is one of the most frequently consumed beverages worldwide. Research on effects of coffee drinking has focused on caffeine; however, coffee contains myriad biochemicals that are chemically unrelated to caffeine, including 3,4-dihydroxyphenyl compounds (catechols) such as caffeic acid and dihydrocaffeic acid (DHCA).

OBJECTIVE

This prospective within-subjects study examined effects of drinking caffeinated or decaffeinated coffee on plasma free (unconjugated) catechols measured by liquid chromatography with series electrochemical detection (LCED) after batch alumina extraction. To confirm coffee-related chromatographic peaks represented catechols, plasma was incubated with catechol-O-methyltransferase and S-adenosylmethionine before the alumina extraction; reductions in peak heights would identify catechols.

METHODS

Ten healthy volunteers drank 2 cups each of caffeinated and decaffeinated coffee on separate days after fasting overnight. With subjects supine, blood was drawn through an intravenous catheter up to 240 min after coffee ingestion and the plasma assayed by alumina extraction followed by LCED.

RESULTS

Within 15 min of drinking coffee of either type, >20 additional peaks were noted in chromatographs from the alumina eluates. Most of the coffee-related peaks corresponded to free catechols. Plasma levels of the catecholamines epinephrine and dopamine increased with both caffeinated and decaffeinated coffee. Levels of other endogenous catechols were unaffected. Plasma DHCA increased bi-phasically, in contrast with other coffee-related free catechols.

INTERPRETATION

Drinking coffee-whether caffeinated or decaffeinated-results in the rapid appearance of numerous free catechols in the plasma. These might affect the disposition of circulating catecholamines. The bi-phasic increase in plasma DHCA is consistent with production by gut bacteria.

Using polyphenols as a relevant therapy to diabetes and its complications, a review

Diabetes is currently a worldwide health concern. Hyperglycemia, hypertension, obesity, and oxidative stress are the major risk factors that inevitably lead to all the complications from diabetes. These complications severely impact the quality of life of patients, and they can be managed, reduced, or even reverted by several polyphenols, plant extracts and foods rich in these compounds. The goal of this review is to approach diabetes not as a single condition but rather an interconnected combination of risk factors and complications. This work shows that polyphenols have multi target action and effects and they have been systematically proven to be relevant in the reduction of each risk factor and improvement of associated complication.

Nutrition and Rheumatoid Arthritis in the 'Omics' Era

Modern high-throughput 'omics' science tools (including genomics, transcriptomics, proteomics, metabolomics and microbiomics) are currently being applied to nutritional sciences to unravel the fundamental processes of health effects ascribed to particular nutrients in humans and to contribute to more precise nutritional advice. Diet and food components are key environmental factors that interact with the genome, transcriptome, proteome, metabolome and the microbiota, and this life-long interplay defines health and diseases state of the individual. Rheumatoid arthritis (RA) is a chronic autoimmune disease featured by a systemic immune-inflammatory response, in genetically susceptible individuals exposed to environmental triggers, including diet. In recent years increasing evidences suggested that nutritional factors and gut microbiome have a central role in RA risk and progression. The aim of this review is to summarize the main and most recent applications of 'omics' technologies in human nutrition and in RA research, examining the possible influences of some nutrients and nutritional patterns on RA pathogenesis, following a nutrigenomics approach. The opportunities and challenges of novel 'omics technologies' in the exploration of new avenues in RA and nutritional research to prevent and manage RA will be also discussed.

Personalized Nutrition and -Omics

With change in global concern toward food quality over food quantity, consumer concern and choice of healthy food has become a matter of prime importance. It gave rise to concept of “personalized or precision nutrition”. The theory behind personalization of nutrition is supported by multiple factors including advances in food analytics, nutrition based diseases and public health programs, increasing use of information technology in nutrition science, concept of gene-diet interaction and growing consumer capacity or concern by better and healthy foods. The advances in “omics” tools and related analytical techniques have resulted into tremendous scope of their application in nutrition science. As a consequence, a better understanding of underlying interaction between diet and individual is expected with addressing of key challenges for successful implementation of this science. In this chapter, the above aspects are discussed to get an insight into driving factors for increasing concern in personalized nutrition.

Chlorogenic Acids in Cardiovascular Disease: A Review of Dietary Consumption, Pharmacology, and Pharmacokinetics

Chlorogenic acids (CGAs) have gained considerable attention as pervasive human dietary constituents with potential cardiovascular-preserving effects. The main sources include coffee, yerba mate, Eucommia ulmodies leaves, and Lonicerae Japonicae Flos. CGA consumption can reduce the risks of hypertension, atherosclerosis, heart failure, myocardial infarction, and other factors associated with cardiovascular risk, such as obesity and type 2 diabetes. This review recapitulates recent advances of CGAs in the cardiovascular-preserving effects, pharmacokinetics, sources, and safety. Emerging evidence indicates that CGAs exhibit circulatory guarding properties through the suppression of oxidative stress, leukocyte infiltration, platelet aggregation, platelet-leukocyte interactions, vascular remodeling, and apoptosis as well as the regulation of glucose and lipid metabolism and vasodilatory action in the cardiovascular system. CGAs exert these effects by acting on complex signaling networks, but the global mechanisms are still not clear. The oral bioavailability of CGA is poor, and there is a potential sensitization concern about CGA. The bioactive metabolites, systematic toxicity, and optimized structure are needed for further identification.

Two apples a day modulate human:microbiome co-metabolic processing of polyphenols, tyrosine and tryptophan

PURPOSE

Validated biomarkers of food intake (BFIs) have recently been suggested as a useful tool to assess adherence to dietary guidelines or compliance in human dietary interventions. Although many new candidate biomarkers have emerged in the last decades for different foods from metabolic profiling studies, the number of comprehensively validated biomarkers of food intake is limited. Apples are among the most frequently consumed fruits and a rich source of polyphenols and fibers, an important mediator for their health-protective properties.

METHODS

Using an untargeted metabolomics approach, we aimed to identify biomarkers of long-term apple intake and explore how apples impact on the human plasma and urine metabolite profiles. Forty mildly hypercholesterolemic volunteers consumed two whole apples or a sugar and energy-matched control beverage, daily for 8 weeks in a randomized, controlled, crossover intervention study. The metabolome in plasma and urine samples was analyzed via untargeted metabolomics.

RESULTS

We found 61 urine and 9 plasma metabolites being statistically significant after the whole apple intake compared to the control beverage, including several polyphenol metabolites that could be used as BFIs. Furthermore, we identified several endogenous indole and phenylacetyl-glutamine microbial metabolites significantly increasing in urine after apple consumption. The multiomic dataset allowed exploration of the correlations between metabolites modulated significantly by the dietary intervention and fecal microbiota species at genus level, showing interesting interactions between Granulicatella genus and phenyl-acetic acid metabolites. Phloretin glucuronide and phloretin glucuronide sulfate appeared promising biomarkers of apple intake; however, robustness, reliability and stability data are needed for full BFI validation.

CONCLUSION

The identified apple BFIs can be used in future studies to assess compliance and to explore their health effects after apple intake. Moreover, the identification of polyphenol microbial metabolites suggests that apple consumption mediates significant gut microbial metabolic activity which should be further explored.

The Effect of Formulation of Curcuminoids on Their Metabolism by Human Colonic Microbiota

Turmeric (Curcuma longa L.) is the only edible plant recognized as a dietary source of curcuminoids, among which curcumin, demethoxycurcumin (DMC) and bis-demethoxycurcumin (Bis-DMC) are the most representative ones. Curcumin shows a very low systemic bioavailability and for this reason, several technologies have been adopted to improve it. These technologies generally improve curcuminoid absorption in the small intestine, however, no data are available about the effect of curcuminoid formulation on colonic biotransformation. The present study aims at investigating the human colonic metabolism of curcuminoids, prepared with two different technologies, using an in vitro model. Unformulated curcuminoid and lecithin-curcuminoid botanical extracts were fermented using an in vitro fecal model and colonic catabolites were identified and quantified by uHPLC-MSⁿ. Native compounds, mainly curcumin, DMC and bis-DMC, were metabolized by colonic microbiota within the 24-h incubation. The degradation of curcuminoids led to the formation of specific curcuminoid metabolites, among which higher concentrations of bis(demethyl)-tetrahydrocurcumin and bis(demethyl)-hexahydrocurcumin were found after lecithin-extract fermentation compared to the concentration detected after unformulated extract. In conclusion, both curcumin-based botanical extracts can be considered important sources of curcuminoids, although the lecithin-formulated extract led to a higher production of curcuminoid catabolites. Moreover, a new curcuminoid catabolite, namely bis(demethyl)-hexahydrocurcumin, has been putatively identified, opening new perspectives in the investigation of curcuminoid bioavailability and their potential metabolite bioactivity.

Quantitative Dietary Fingerprinting (QDF)-A Novel Tool for Comprehensive Dietary Assessment Based on Urinary Nutrimetabolomics

Accurate dietary assessment is a challenge in nutritional research, needing powerful and robust tools for reliable measurement of food intake biomarkers. In this work, we have developed a novel quantitative dietary fingerprinting (QDF) approach, which enables for the first time the simultaneous quantitation of about 350 urinary food-derived metabolites, including (poly)phenolic aglycones, phase II metabolites, and microbial-transformed compounds, as well as other compounds (e.g., glucosinolates, amino acid derivatives, methylxanthines, alkaloids, and markers of alcohol and tobacco consumption). This method was fully validated for 220 metabolites, yielding good linearity, high sensitivity and precision, accurate recovery rates, and negligible matrix effects. Furthermore, 127 additional phase II metabolites were also included in this method after identification in urines collected from acute dietary interventions with various foods. Thus, this metabolomic approach represents one-step further toward precision nutrition and the objective of improving the accurateness and comprehensiveness in the assessment of dietary patterns and lifestyles.

3-(4-Hydroxy-3-methoxyphenyl)propionic Acid Produced from 4-Hydroxy-3-methoxycinnamic Acid by Gut Microbiota Improves Host Metabolic Condition in Diet-Induced Obese Mice

4-Hydroxy-3-methoxycinnamic acid (HMCA), a hydroxycinnamic acid derivative, is abundant in fruits and vegetables, including oranges, carrots, rice bran, and coffee beans. Several beneficial effects of HMCA have been reported, including improvement of metabolic abnormalities in animal models and human studies. However, its mitigating effects on high-fat diet (HFD)-induced obesity, and the mechanism underlying these effects, remain to be elucidated. In this study, we demonstrated that dietary HMCA was efficacious against HFD-induced weight gain and hepatic steatosis, and that it improved insulin sensitivity. These metabolic benefits of HMCA were ascribable to 3-(4-hydroxy-3-methoxyphenyl)propionic acid (HMPA) produced by gut microbiota. Moreover, conversion of HMCA into HMPA was attributable to a wide variety of microbes belonging to the phylum Bacteroidetes. We further showed that HMPA modulated gut microbes associated with host metabolic homeostasis by increasing the abundance of organisms belonging to the phylum Bacteroidetes and reducing the abundance of the phylum Firmicutes. Collectively, these results suggest that HMPA derived from HMCA is metabolically beneficial, and regulates hepatic lipid metabolism, insulin sensitivity, and the gut microbial community. Our results provide insights for the development of functional foods and preventive medicines, based on the microbiota of the intestinal environment, for the prevention of metabolic disorders.

Plasma Metabolites Associated with Coffee Consumption: A Metabolomic Approach within the PREDIMED Study

Few studies have examined the association of a wide range of metabolites with total and subtypes of coffee consumption. The aim of this study was to investigate associations of plasma metabolites with total, caffeinated, and decaffeinated coffee consumption. We also assessed the ability of metabolites to discriminate between coffee consumption categories. This is a cross-sectional analysis of 1664 participants from the PREDIMED study. Metabolites were semiquantitatively profiled using a multiplatform approach. Consumption of total coffee, caffeinated coffee and decaffeinated coffee was assessed by using a validated food frequency questionnaire. We assessed associations between 387 metabolite levels with total, caffeinated, or decaffeinated coffee consumption (≥50 mL coffee/day) using elastic net regression analysis. Ten-fold cross-validation analyses were used to estimate the discriminative accuracy of metabolites for total and subtypes of coffee. We identified different sets of metabolites associated with total coffee, caffeinated and decaffeinated coffee consumption. These metabolites consisted of lipid species (e.g., sphingomyelin, phosphatidylethanolamine, and phosphatidylcholine) or were derived from glycolysis (alpha-glycerophosphate) and polyphenol metabolism (hippurate). Other metabolites included caffeine, 5-acetylamino-6-amino-3-methyluracil, cotinine, kynurenic acid, glycocholate, lactate, and allantoin. The area under the curve (AUC) was 0.60 (95% CI 0.56-0.64), 0.78 (95% CI 0.75-0.81) and 0.52 (95% CI 0.49-0.55), in the multimetabolite model, for total, caffeinated, and decaffeinated coffee consumption, respectively. Our comprehensive metabolic analysis did not result in a new, reliable potential set of metabolites for coffee consumption.

Antioxidant and nephroprotection activities of Combretum micranthum: A phytochemical, in-vitro and ex-vivo studies

Management of chronic renal failure is exceedingly expensive. Despite of encouraging experimental outcomes, there is a lack of potent nephroprotective drugable molecules in a clinics or market. To develop a nephroprotective phytomedicine, the present study was designed to do a literature survey on reported phytochemical and biological analysis of Combretum micranthum and to carry out chemoprofiling, in-vitro antioxidant and ex-vivo nephroprotective capacity of the title plant. The phytochemical and biological activity survey of C. micranthum has reveals the presence of many bioactive compounds such as flavonoids, terpenoids, steroids and alkaloids with many biological activities. Phytochemical investigation re-confirmed the presence of these compounds. Hydroalcoholic extract of C. micranthum (CM extract) showed a strong antioxidant activity by scavenging AAPH, DPPH, nitric oxide, hydrogen peroxide and chelating metal ions. CM extract exhibited significant (P < 0.001) dose dependent inhibition of ferric chloride-ascorbic acid induced lipid peroxidation. Diabetic nephropathy is a serious and common complication leading to end stage renal disease. Therefore, in the present study, glucose-induced toxicity was also studied in human embryonic kidney cells (HEK-293) as an in vitro model for diabetic nephropathy. The results showed that exposure of cells to high glucose (100 mM) for 72 h significantly reduced the cell viability resulting in morphological changes such as cell shrinkage, rounded cell shape and cytoplasmic vacuolation. Treatment with CM extract at 10 and 25 μg/mL resulted in significant improvement in cell viability from 10 to 23% compared to the high glucose control. This study demonstrated the potential antioxidant and nephroprotective properties of C. micranthum, justifying its traditional use in the treatment of various diseases.

Consumption of Chlorogenic Acids through Coffee and Health Implications

Chlorogenic acids (CGA) are the main antioxidant compounds in the Western diet, due to their high concentrations in coffee associated with the high consumption of the beverage. Until about 10 years ago, like many other phenolic compounds, CGA were thought to be poorly absorbed in the human digestive system. Along the years, large amounts of information on the absorption and metabolism of these compounds have been unveiled, and today, it is known that, on average, about one third of the consumed CGA from coffee is absorbed in the human gastrointestinal tract, although large inter-individual variation exists. Considering results from in vitro animal and human studies, it is possible to conclude that the antioxidant and anti-inflammatory effects of coffee CGA are responsible for, at least to a certain extent, the association between coffee consumption and lower incidence of various degenerative and non-degenerative diseases, in addition to higher longevity.

A critical review on grape polyphenols for neuroprotection: Strategies to enhance bioefficacy

The aging of populations worldwide is driving greater demands for dietary polyphenols which have been recognized as promising prophylactic and/or therapeutic agents in the context of neurodegeneration, and are ubiquitously present in plant-based diets. In particular, grape-derived products encompass a wide array of phenolic compounds purported with multiple health benefits including neuroprotective efficacy. Despite the increasing preclinical and clinical evidence demonstrating high potential of grape polyphenol (GPP)-rich botanicals in preventing and attenuating diverse neurodegenerative disorders, the limited bioavailability of GPPs, especially in the brain, generates questions as to their applications and effectiveness in neuroprotection. To address this issue, significant research efforts have been made to enhance oral bioavailability of GPPs via application of novel strategies. This review highlights some critical issues related to the bioavailability and neuroprotective efficacy of GPPs and GPP-rich botanicals. The representative bioavailability-enhancing strategies are critically reviewed to provide practical solutions for augmenting the bioefficacy of GPP-rich botanicals. Synergistic applications of encapsulation techniques (for physiochemical protection and bypassing xenobiotic metabolism) and dietary intervention strategies involving modulation of gut microbiota (for generating more bioavailable phenolic metabolites) appear promising, and may substantially enhance the bioefficacy, especially the neuroprotective efficacy, of orally consumed GPPs.

Guarana (Paullinia cupana Mart.) alters gut microbiota and modulates redox status, partially via caffeine in Wistar rats

Microbiota alterations are observed in pathological conditions, and their regulation is a subject of great interest. Gut microbes are affected by diet, and plant polyphenols may have positive effect on gut microbiota; however, plant-derived extracts may have toxic effects. Guarana (Paullinia cupana Mart.) is a nontraditional medicinal plant applied worldwide. Guarana yields an alkaloid and polyphenol-rich seed with antimicrobial, antioxidant, and anti-inflammatory properties, where caffeine is the major compound. We evaluated the effects of guarana seed powder (GSP) and purified caffeine on gut microbial composition and redox and inflammatory parameters in Wistar rats after 21 days of treatment. Fecal microbiota was analyzed utilizing 16S rDNA sequencing. Antioxidant enzymes activities from liver, kidney, and colon, as well as oxidative damage markers, were evaluated. Total nonenzymatic antioxidant potential was also evaluated. Microbiota was altered by both treatments, GSP and caffeine, without loss of diversity. In the liver, the kidney, and the colon, we observed a decrease in the antioxidant enzymes activities in the GSP group with no increase in the expression of oxidative damage markers, although some enzymes were also regulated by caffeine. Taken together, these results suggested that GSP ameliorates redox parameters but negatively affected gut microbiota, partially via caffeine.

Bioavailability of hydroxycinnamates in an instant green/roasted coffee blend in humans. Identification of novel colonic metabolites

Roasting greatly reduces the phenolic content in green coffee beans. Considering the beneficial effects of coffee polyphenols, blends containing green coffee beans are being consumed as a healthier alternative to roasted coffee. This study was aimed at assessing the absorption and metabolism of hydroxycinnamates in an instant green/roasted (35/65) coffee blend in healthy humans. Twelve fasting men and women consumed a cup of coffee containing 269.5 mg (760.6 μmol) of chlorogenic acids. Blood and urine samples were taken before and after coffee consumption at different times and analyzed by LC-MS-QToF. Up to 25 and 42 metabolites were identified in plasma and urine, respectively, mainly in the form of sulfate and methyl derivatives, and to a lower extent as glucuronides. Un-metabolized hydroxycinnamate esters (caffeoyl-, feruloyl-, and coumaroylquinic acids), hydroxycinnamic acids (caffeic, ferulic and coumaric acids) and their phase II metabolites, in addition to phase II derivatives of lactones, represented a minor group of metabolites (16.3% of the metabolites excreted in urine) with kinetics compatible with small intestine absorption. Dihydrohydroxycinnamic acids and their phase II derivatives, in addition to feruloylglycine, showed delayed kinetics due to their colonic origin and represented the most abundant group of metabolites (75.7% of total urinary metabolites). Dihydrohydroxycinnamate esters (dihydroferuloyl-, dihydrocaffeoyl- and dihydrocoumaroylquinic acids) have been identified for the first time in both plasma and urine, with microbial origin (excreted 8-12 h after coffee intake) amounting to 8% of total urinary metabolites. In conclusion, coffee polyphenols are partially bioavailable and extensively metabolized, mainly by the colonic microbiota.

Host: Microbiome co-metabolic processing of dietary polyphenols - An acute, single blinded, cross-over study with different doses of apple polyphenols in healthy subjects

Apples are one of the most commonly consumed fruits and their high polyphenol content is considered one of the most important determinants of their health-promoting activities. Here we studied the nutrikinetics of apple polyphenols by UHPLC-HRMS metabolite fingerprinting, comparing bioavailability when consumed in a natural or a polyphenol-enriched cloudy apple juice. Twelve men and women participated in an acute single blind controlled crossover study in which they consumed 250 mL of cloudy apple juice (CAJ), Crispy Pink apple variety, or 250 mL of the same juice enriched with 750 mg of an apple polyphenol extract (PAJ). Plasma and whole blood were collected at time 0, 1, 2, 3 and 5 h. Urine was collected at time 0 and 0-2, 2-5, 5-8, and 8-24 h after juice consumption. Faecal samples were collected from each individual during the study for 16S rRNA gene profiling. As many as 110 metabolites were significantly elevated following intake of polyphenol enriched cloudy apple juice, with large inter-individual variations. The comparison of the average area under the curve of circulating metabolites in plasma and in urine of volunteers consuming either the CAJ or the PAJ demonstrated a stable metabotype, suggesting that an increase in polyphenol concentration in fruit does not limit their bioavailability upon ingestion. Faecal bacteria were correlated with specific microbial catabolites derived from apple polyphenols. Human metabolism of apple polyphenols is a co-metabolic process between human encoded activities and those of our resident microbiota. Here we have identified specific blood and urine metabolic biomarkers of apple polyphenol intake and identified putative associations with specific genera of faecal bacteria, associations which now need confirmation in specifically designed mechanistic studies.

Use of Metabolomics in Improving Assessment of Dietary Intake

BACKGROUND

Nutritional metabolomics is rapidly evolving to integrate nutrition with complex metabolomics data to discover new biomarkers of nutritional exposure and status.

CONTENT

The purpose of this review is to provide a broad overview of the measurement techniques, study designs, and statistical approaches used in nutrition metabolomics, as well as to describe the current knowledge from epidemiologic studies identifying metabolite profiles associated with the intake of individual nutrients, foods, and dietary patterns.

SUMMARY

A wide range of technologies, databases, and computational tools are available to integrate nutritional metabolomics with dietary and phenotypic information. Biomarkers identified with the use of high-throughput metabolomics techniques include amino acids, acylcarnitines, carbohydrates, bile acids, purine and pyrimidine metabolites, and lipid classes. The most extensively studied food groups include fruits, vegetables, meat, fish, bread, whole grain cereals, nuts, wine, coffee, tea, cocoa, and chocolate. We identified 16 studies that evaluated metabolite signatures associated with dietary patterns. Dietary patterns examined included vegetarian and lactovegetarian diets, omnivorous diet, Western dietary patterns, prudent dietary patterns, Nordic diet, and Mediterranean diet. Although many metabolite biomarkers of individual foods and dietary patterns have been identified, those biomarkers may not be sensitive or specific to dietary intakes. Some biomarkers represent short-term intakes rather than long-term dietary habits. Nonetheless, nutritional metabolomics holds promise for the development of a robust and unbiased strategy for measuring diet. Still, this technology is intended to be complementary, rather than a replacement, to traditional well-validated dietary assessment methods such as food frequency questionnaires that can measure usual diet, the most relevant exposure in nutritional epidemiologic studies.

Absorption and metabolism of yerba mate phenolic compounds in humans

Bioavailability of yerba mate phenolic compounds was assessed in healthy humans. More than 34 metabolites were identified in biological fluids, mainly sulfated conjugates of caffeic and ferulic/isoferulic acids, in addition to non-metabolized caffeoyl-, feruloyl- and p-coumaroilquinic acids, with rapid appearance and clearance in plasma indicative of small intestinal absorption. These compounds amounted to 13.1% of the urinary metabolites. Delayed absorption of dihydrocaffeic, dihydroferulic and dihydrocoumaric acids and their phase II metabolites, in addition to feruloylglycine, pointed to their microbial origin and colonic absorption, accounting for 81.0% of excreted metabolites. Phase II flavonol metabolites (0.2%) derived mainly from rutin after colonic transformation and absorption were also detected. Additionally, dihydroferuloyl-, dihydrocaffeoyl- and dihydrocoumaroylquinic acids (5.7%) were identified, showing the most delayed kinetics. Total phenolic excretion (147.6μmol) corresponded to 13.2% of ingested phenols. In conclusion, yerba mate polyphenols are partially bioavailable and extensively metabolized, mainly by the colonic microbiota.

Influence of omega-3 PUFAs on the metabolism of proanthocyanidins in rats

Studies of the bioavailability of proanthocyanidins usually consider them independently of other dietary constituents, while there is a tendency in the field of functional foods towards the combination of different bioactive compounds in a single product. This study examined the long-term effects of ω-3 polyunsaturated fatty acids of marine origin on the metabolic fate of grape proanthocyanidins. For this, female adult Wistar-Kyoto rats were fed (18weeks) with a standard diet supplemented or not with eicosapentaenoic acid/docosahexaenoic acid (1:1, 16.6g/kg feed), proanthocyanidin-rich grape seed extract (0.8g/kg feed) or both. A total of 39 microbial-derived metabolites and 16 conjugated metabolites were detected by HPLC-MS/MS either in urine or in the aqueous fraction of feces. An unexpected significant increase in many proanthocyanidin metabolites in urine and feces was observed in the group supplemented with ω-3 polyunsaturated fatty acids group as compared to the animals fed a standard diet, which contains a small amount of polyphenols. However, proanthocyanidin metabolites in rats given ω-3 polyunsaturated fatty acids and grape seed extract did not significantly differ from those in the group supplemented only with grape seed extract. It was concluded that ω-3 polyunsaturated fatty acids collaborate in the metabolism of polyphenols when present at low doses in the feed matrix, while the capacity of ω-3 polyunsaturated fatty acids to induce microbiota transformations when proanthocyanidins are present at high doses is not relevant compared to that of polyphenols themselves.

Ferulic acid-4-O-sulfate rather than ferulic acid relaxes arteries and lowers blood pressure in mice

Consumption of foods rich in ferulic acid (FA) such as wholegrain cereals, or FA precursors such as chlorogenic acids in coffee, is inversely correlated with risk of cardiovascular disease and type 2 diabetes. As a result of digestion and phase II metabolism in the gut and liver, FA is converted predominantly into ferulic acid-4-O-sulfate (FA-sul), an abundant plasma metabolite. Although FA-sul is the main metabolite, very little has been reported regarding its bioactivities. We have compared the ex vivo vasorelaxing effect of FA and FA-sul (10^-7-3.10^-5M) on isolated mouse arteries mounted in tissue myographs. FA-sul, but not FA, elicited a concentration-dependent vasorelaxation of saphenous and femoral arteries and aortae. The FA-sul-mediated vasorelaxation was blunted by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a soluble guanylate cyclase (sGC) inhibitor. The role of sGC was confirmed in femoral arteries isolated from sGCα₁^(-/-) knockout mice. Furthermore, 4-aminopyridine, a specific inhibitor of voltage-dependent potassium channels, significantly decreased FA-sul-mediated effects. In anesthetized mice, intravenous injection of FA-sul decreased mean arterial pressure, whereas FA had no effect, confirming the results obtained ex vivo. FA-sul is probably one of the major metabolites accounting for the blood pressure-lowering effects associated with FA consumption.

Detection of 191 Taxifolin Metabolites and Their Distribution in Rats Using HPLC-ESI-IT-TOF-MS(n)

Taxifolin is a ubiquitous bioactive constituent of foods and herbs. To thoroughly explore its metabolism in vivo, an HPLC-ESI-IT-TOF-MSⁿ method combined with specific metabolite detection strategy was used to detect and identify the metabolites of taxifolin in rats. Of the 191 metabolites tentatively identified, 154 were new metabolites, 69 were new compounds and 32 were dimers. This is the first report of the in vivo biotransformation of a single compound into more than 100 metabolites. Furthermore, acetylamination and pyroglutamic acid conjugation were identified as new metabolic reactions. Seventeen metabolites were found to have various taxifolin-related bioactivities. The potential targets of taxifolin and 63 metabolites were predicted using PharmMapper, with results showing that more than 60 metabolites have the same five targets. Metabolites with the same fragment pattern may have the same pharmacophore. Thus these metabolites may exert the same pharmacological effects as taxifolin through an additive effect on the same drug targets. This observation indicates that taxifolin is bioactive not only in the parent form, but also through its metabolites. These findings enhance understanding of the metabolism and effective forms of taxifolin and may provide further insight of the beneficial effects of taxifolin and its derivatives.

Comparing metabolite profiles of habitual diet in serum and urine

BACKGROUND

Diet plays an important role in chronic disease etiology, but some diet-disease associations remain inconclusive because of methodologic limitations in dietary assessment. Metabolomics is a novel method for identifying objective dietary biomarkers, although it is unclear what dietary information is captured from metabolites found in serum compared with urine.

OBJECTIVE

We compared metabolite profiles of habitual diet measured from serum with those measured from urine.

DESIGN

We first estimated correlations between consumption of 56 foods, beverages, and supplements assessed by a food-frequency questionnaire, with 676 serum and 848 urine metabolites identified by untargeted liquid chromatography mass spectrometry, ultra-high performance liquid chromatography tandem mass spectrometry, and gas chromatography mass spectrometry in a colon adenoma case-control study (n = 125 cases and 128 controls) while adjusting for age, sex, smoking, fasting, case-control status, body mass index, physical activity, education, and caloric intake. We controlled for multiple comparisons with the use of a false discovery rate of <0.1. Next, we created serum and urine multiple-metabolite models to predict food intake with the use of 10-fold crossvalidation least absolute shrinkage and selection operator regression for 80% of the data; predicted values were created in the remaining 20%. Finally, we compared predicted values with estimates obtained from self-reported intake for metabolites measured in serum and urine.

RESULTS

We identified metabolites associated with 46 of 56 dietary items; 417 urine and 105 serum metabolites were correlated with ≥1 food, beverage, or supplement. More metabolites in urine (n = 154) than in serum (n = 39) were associated uniquely with one food. We found previously unreported metabolite associations with leafy green vegetables, sugar-sweetened beverages, citrus, added sugar, red meat, shellfish, desserts, and wine. Prediction of dietary intake from multiple-metabolite profiles was similar between biofluids.

CONCLUSIONS

Candidate metabolite biomarkers of habitual diet are identifiable in both serum and urine. Urine samples offer a valid alternative or complement to serum for metabolite biomarkers of diet in large-scale clinical or epidemiologic studies.

Development and validation of a high-throughput micro solid-phase extraction method coupled with ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry for rapid identification and quantification of phenolic metabolites in human plasma and urine

A rapid and high-throughput micro-solid phase extraction (μ-SPE) method coupled with ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC Q-TOF MS) analysis was optimized and validated for the quantification of 67 (poly)phenol metabolites in human plasma and urine using authentic standards. The method was fully validated in terms of specificity, linearity, method detection limit (MDL), method quantification limit (MQL), repeatability, intra- and inter-day precision, accuracy and matrix effects. The method proved to be specific and results showed linearity of responses for all compounds, with MDL ranging between 0.04nM and 86nM in plasma and between 0.01nM and 136nM in urine. MQL ranged between 0.14nM and 286nM in plasma and between 0.03nM and 465nM in urine. Repeatability varied between 1.7 and 9.2% in plasma and between 2.2% and 10.4% in urine. Median precision values of 8.7 and 11.5% (intra-day), and 10.8% and 10.0% (inter-day) were obtained in plasma and urine, respectively. The median recovery was 89% in both biological matrices. Matrix effects were determined and median values of -1.2% and -6.8% in plasma and urine were obtained. After method validation, 49 and 57 compounds, including phase II and gut microbial metabolites, were quantified in plasma and urine, respectively, following cranberry juice consumption. This methodology can be applied to large-scale human dietary intervention trials allowing for high sample throughput.

GC/MS method to quantify bioavailable phenolic compounds and antioxidant capacity determination of plasma after acute coffee consumption in human volunteers

Coffee, a source of chlorogenic acids (CGAs), is recognized for preventing chronic diseases associated with oxidative stress. Therefore, sensitive, selective and easy access methods for the determination of the bioavailability and antioxidant function in vivo are required in clinical studies. The aim of this work was to validate a GC/MS method to quantify caffeic acid (CA) and ferulic acid (FA) and to apply different methodologies to determine the antioxidant capacity of plasma after the acute consumption of 420mg of CGAs provided by 400mL of coffee. The intervention was performed in 20 adults (6 men and 14 women) with a mean±SD age of 35.7±9.0 and body mass index of 22.1±1.6kg who were assigned to 2 groups: a control group and a group that consumed coffee. The validated analytical GC/MS method was exact, precise and selective. The selected derivatizing reagent was N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tertbutyldimethylchlorosilane (MTBSTFA+1% TBDMSCl). The method was reproducible, and the limit of detection (LOD) was 3nM for CA and 5nM for FA. CA and FA were detected in plasma 1h after coffee intake and were undetectable in the control group. Compared to the baseline values, the antioxidant capacity of plasma significantly increased when it was measured by ferric reducing antioxidant power (FRAP) (6.67%; P<0.001) and by oxygen radical absorbance capacity (ORAC) (7.16%; P<0.05). The in vitro and ex vivo experiments on plasma with CA and FA showed a significant increase of the antioxidant activity (P<0.05) as well as delay of LDL oxidation (P<0.001). The method validated by GC/MS was proposed as an alternative for evaluating the bioavailability of ACG after acute coffee intake. The need for in vitro methodologies was demonstrated to determine the antioxidant activity.

Characterization of metabolites in rats after intravenous administration of salvianolic acid for injection by ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry

It is an essential requirement to clarify the metabolites of traditional Chinese medicine (TCM) injections, which contain numerous ingredients, to assess their safe and effective use in clinic. Salvianolic acid for injection (SAFI), made from hydrophilic phenolic acids in Salvia miltiorrhiza Bunge, has been widely used for the treatment of cerebrovascular diseases, but information on its metabolites in vivo is still lacking. In the present study, we aimed to holistically characterize the metabolites of the main active ingredients in rat plasma, bile, urine and feces following intravenous administration of SAFI. An ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method was developed. Combining information on retention behaviors, multistage mass spectra and literature data, a total of eight prototypes and 52 metabolites were tentatively characterized. Metabolites originated from rosmarinic acid and salvianolic acid B comprised the majority of identified compounds. Meanwhile, four metabolites derived from salvianolic acid D and five from salvianolic acid B are reported for the first time. This study revealed that methylation, sulfation and glucuronidation were the major metabolic pathways of phenolic acids in SAFI in vivo. Furthermore, the developed UPLC/Q-TOF-MS method could also benefit the metabolic investigation of extracts and preparations in TCM with hydrophilic ingredients. Copyright © 2016 John Wiley & Sons, Ltd.

Coffee provides a natural multitarget pharmacopeia against the hallmarks of cancer

Coffee is the second most popular beverage in the world after water with a consumption of approximately two billion cups per day. Due to its low cost and ease of preparation, it is consumed in almost all countries and by all social classes of the population through different modes of preparation. Despites its simple appearance, a cup of coffee is in fact a complex mixture that contains hundreds of molecules, the composition and concentration of which vary widely and depend on factors including the origin of the coffee tree or its metabolism. Although an excessive consumption of coffee can be harmful, many molecules that are present in this black decoction exert anticancer properties. This review aims to describe the different primary coffee-containing substances that exert chemopreventive and bioactive activities against the different hallmarks and enabling characteristics of cancer, thus explaining the anticancer health benefit of black coffee.

Protective Effects of Dihydrocaffeic Acid, a Coffee Component Metabolite, on a Focal Cerebral Ischemia Rat Model

We recently reported the protective effects of chlorogenic acid (CGA) in a transient middle cerebral artery occlusion (tMCAo) rat model. The current study further investigated the protective effects of the metabolites of CGA and dihydrocaffeic acid (DHCA) was selected for further study after screening using the same tMCAo rat model. In the current study, tMCAo rats (2 h of MCAo followed by 22 h of reperfusion) were injected with various doses of DHCA at 0 and 2 h after onset of ischemia. We assessed brain damage, functional deficits, brain edema, and blood-brain barrier damage at 24 h after ischemia. For investigating the mechanism, in vitro zymography and western blotting analysis were performed to determine the expression and activation of matrix metalloproteinase (MMP)-2 and -9. DHCA (3, 10, and 30 mg/kg, i.p.) dose-dependently reduced brain infarct volume, behavioral deficits, brain water content, and Evans Blue (EB) leakage. DHCA inhibited expression and activation of MMP-2 and MMP-9. Therefore, DHCA might be one of the important metabolites of CGA and of natural products, including coffee, with protective effects on ischemia-induced neuronal damage and brain edema.

Toward systems epidemiology of coffee and health

PURPOSE OF REVIEW

Coffee is one of the most widely consumed beverages in the world and has been associated with many health conditions. This review examines the limitations of the classic epidemiological approach to studies of coffee and health, and describes the progress in systems epidemiology of coffee and its correlated constituent, caffeine. Implications and applications of this growing body of knowledge are also discussed.

RECENT FINDINGS

Population-based metabolomic studies of coffee replicate coffee-metabolite correlations observed in clinical settings but have also identified novel metabolites of coffee response, such as specific sphingomyelin derivatives and acylcarnitines. Genome-wide analyses of self-reported coffee and caffeine intake and serum levels of caffeine support an overwhelming role for caffeine in modulating the coffee consumption behavior. Interindividual variation in the physiological exposure or response to any of the many chemicals present in coffee may alter the persistence and magnitude of their effects. It is thus imperative that future studies of coffee and health account for this variation.

SUMMARY

Systems epidemiological approaches promise to inform causality, parse the constituents of coffee responsible for health effects, and identify the subgroups most likely to benefit from increasing or decreasing coffee consumption.

Bioavailability, bioactivity and impact on health of dietary flavonoids and related compounds: an update

There is substantial interest in the role of plant secondary metabolites as protective dietary agents. In particular, the involvement of flavonoids and related compounds has become a major topic in human nutrition research. Evidence from epidemiological and human intervention studies is emerging regarding the protective effects of various (poly)phenol-rich foods against several chronic diseases, including neurodegeneration, cancer and cardiovascular diseases. In recent years, the use of HPLC-MS for the analysis of flavonoids and related compounds in foods and biological samples has significantly enhanced our understanding of (poly)phenol bioavailability. These advancements have also led to improvements in the available food composition and metabolomic databases, and consequently in the development of biomarkers of (poly)phenol intake to use in epidemiological studies. Efforts to create adequate standardised materials and well-matched controls to use in randomised controlled trials have also improved the quality of the available data. In vitro investigations using physiologically achievable concentrations of (poly)phenol metabolites and catabolites with appropriate model test systems have provided new and interesting insights on potential mechanisms of actions. This article will summarise recent findings on the bioavailability and biological activity of (poly)phenols, focusing on the epidemiological and clinical evidence of beneficial effects of flavonoids and related compounds on urinary tract infections, cognitive function and age-related cognitive decline, cancer and cardiovascular disease.

Human metabolome associates with dietary intake habits among African Americans in the atherosclerosis risk in communities study

The human metabolome is a measurable outcome of interactions among an individual's inherited genome, microbiome, and dietary intake. We explored the relationship between dietary intake and serum untargeted metabolomic profiles in a subsample of 1,977 African Americans from the Atherosclerosis Risk in Communities (ARIC) Study in 1987-1989. For each metabolite, we conducted linear regression to estimate its relationships with each food group and food category. Potential confounding factors included age, sex, body mass index (weight (kg)/height (m)(2)), energy intake, kidney function, and food groups. We used a modified Bonferroni correction to determine statistical significance. In total, 48 pairs of diet-metabolite associations were identified, including multiple novel associations. The food group "sugar-rich foods and beverages" was inversely associated with 5 metabolites in the 2-hydroxybutyrate-related subpathway and positively associated with 5 γ-glutamyl dipeptides. The hypothesized mechanism of these associations may be through oxidative stress. "Sugar-rich foods and beverages" were also inversely associated with 7 unsaturated long-chain fatty acids. These findings suggest that the contribution of a sugar-rich dietary pattern to increased cardiovascular disease risk may be partially attributed to oxidative stress and disordered lipid profiles. Metabolomics may reveal novel metabolic biomarkers of dietary intake and provide insight into biochemical pathways underlying nutritional effects on disease development.

Chronic coffee consumption in the diet-induced obese rat: impact on gut microbiota and serum metabolomics

Epidemiological data confirms a strong negative association between regular coffee consumption and the prevalence of type 2 diabetes. Coffee is initially absorbed in the stomach and small intestine but is further fermented in the colon by gut microbiota. The bioavailability, production and biological activity of coffee polyphenols is modulated, in part, by gut microbiota. The purpose of this study was to determine if chronic coffee consumption could mitigate negative gut microbiota and metabolomic profile changes induced by a high-fat diet. Male Sprague-Dawley rats were randomized to chow (12% kcal fat) or high-fat (60% kcal fat) diet. Each group was further divided into water or caffeinated coffee for 10 weeks. Coffee consumption in high-fat-fed rats was associated with decreased body weight, adiposity, liver triglycerides and energy intake. Despite a more favorable body composition, rats displayed profound systemic insulin resistance, likely due to caffeine. Coffee consumption attenuated the increase in Firmicutes (F)-to-Bacteroidetes (B) ratio and Clostridium Cluster XI normally associated with high-fat feeding but also resulted in augmented levels of Enterobacteria. In the serum metabolome, coffee had a distinct impact, increasing levels of aromatic and circulating short-chain fatty acids while lowering levels of branched-chain amino acids. In summary, coffee consumption is able to alter gut microbiota in high-fat-fed rats although the role of these changes in reducing diabetes risk is unclear given the increased insulin resistance observed with coffee in this study.

Coffee modulates transcription factor Nrf2 and highly increases the activity of antioxidant enzymes in rats

This study investigated the effect of a 28 day administration of coffee brew on the activity of antioxidant enzymes in rats. After this period of 2.0 mL/day dosages of this beverage, the activities of hepatic superoxide dismutase, catalase, and glutathione peroxidase increased 74.8, 59.4, and 135.2%, respectively, whereas the cytosolic level of Nrf2 increased 131.3%. At the same time, the total antioxidant capacity of the hepatic tissue increased 25.1%, improving the defensive status against oxidative stress. At the end of the experiment, the levels of biomarkers alanine transaminase and aspartate transaminase remained equal to the control group, and no changes were observed in the hepatic histoarchiteture of the animals, suggesting that the liver tissue was not impaired by the exposure to coffee. The changes in enzyme activities and antioxidant capacity were statistically significant (p < 0.05), indicating that coffee could be considered an important alternative against oxidative stress and its correlated degenerative diseases.

Coffee: biochemistry and potential impact on health

This article reviews the diversity of compounds found in coffee beans, the effect of roasting and the potential impact of coffee beverage on health.

The role of oxygen in the liquid fermentation of wheat bran

The extensive use of wheat bran as a food ingredient is limited due to its bitter taste and hard texture. To overcome these, some preprocessing methods, such as fermentation with yeast and lactic acid bacteria or enzymatic treatments have been proposed. The current work studied microbial communities, acidification, ethanol formation and metabolite profile of wheat bran fermented in either aerated or anaerobic conditions. In aerated conditions, yeasts grew better and the production of organic acids was smaller, and hence pH was higher. In anaerobic conditions, lactic acid bacteria and endogenous heterotrophic bacteria grew better. Aeration had a large effect on the sourdough metabolite profile, as analyzed by UPLC-qTOF-MS. Anaerobic conditions induced degradation of ferulic and caffeic acids, whereas the amount of sinapic acid increased. Aeration caused degradation of amino acids and hydroxycinnamic acid derivatives of polyamines. The results suggest that the control of oxygen could be used for tailoring the properties of bran sourdough.

Bioavailability of Plant-Derived Antioxidants

Natural products with antioxidant properties have been extensively utilized in the pharmaceutical and food industry and have also been very popular as health-promoting herbal products. This review provides a summary of the literature published around the first decade of the 21st century regarding the oral bioavailability of carotenoids, polyphenols and sulfur compounds as the three major classes of plant-derived antioxidants. The reviewed original research includes more than 40 compounds belonging to the above mentioned classes of natural antioxidants. In addition, related reviews published during the same period have been cited. A brief introduction to general bioavailability-related definitions, procedures and considerations is also included.