New insights into the bioavailability of red raspberry anthocyanins and ellagitannins

Transcriptomic, Proteomic and Metabolomic Analysis of Flavonoid Biosynthesis During Fruit Maturation in Rubus chingii Hu

Rubus chingii HU, is a medicinal and nutritious fruit, which is very rich in flavonoids. However, the biosynthesis of its flavonoids is poorly understood. This study examined flavonoids and the genes/proteins at four fruit ripening phases using LC-MS/MS and qPCR. Six major kinds of anthocyanins, primarily consisted of flavanol-anthocyanins, which differed in form or concentration from other Rubus species. In contrast to other known raspberries species, R. chingii had a decline in flavonoids during fruit ripening, which was due to down-regulation of genes and proteins involved in phenylpropanoid and flavonoid biosynthesis. Unexpectedly, anthocyanin also continuously decreased during fruit maturation. This suggests that anthocyanins are not responsible for the fruit's reddish coloration. Flavanol-anthocyanins were derived from the proanthocyanidin pathway, which consumed two flavonoid units both produced through the same upstream pathway. Their presence indicates a reduction in the potential biosynthesis of anthocyanin production. Also, the constantly low expression of RchANS gene resulted in low levels of anthocyanin biosynthesis. The lack of RchF3'5'H gene/protein hindered the production of delphinidin glycosides. Flavonoids primarily comprising of quercetin/kaempferol-glycosides were predominately located at fruit epidermal-hair and placentae. The proportion of receptacle/drupelets changes with the maturity of the fruit and may be related to a decrease in the content of flavonoids per unit mass as the fruit matures. The profile and biosynthesis of R. chingii flavonoids are unique to Rubus. The unique flavonol pathways of R. chingii could be used to broaden the genetic diversity of raspberry cultivars and to improve their fruit quality.

Dietary Effects of Anthocyanins in Human Health: A Comprehensive Review

In recent years, the consumption of natural-based foods, including beans, fruits, legumes, nuts, oils, vegetables, spices, and whole grains, has been encouraged. This fact is essentially due to their content in bioactive phytochemicals, with the phenolic compounds standing out. Among them, anthocyanins have been a target of many studies due to the presence of catechol, pyrogallol, and methoxy groups in their chemical structure, which confer notable scavenging, anti-apoptotic, and anti-inflammatory activities, being already recommended as supplementation to mitigate or even attenuate certain disorders, such as diabetes, cancer, and cardiovascular and neurological pathologies. The most well-known anthocyanins are cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside. They are widespread in nature, being present in considerable amounts in red fruits and red vegetables. Overall, the present review intends to discuss the most recent findings on the potential health benefits from the daily intake of anthocyanin-rich foods, as well as their possible pharmacological mechanisms of action. However, before that, some emphasis regarding their chemical structure, dietary sources, and bioavailability was done.

Review of Functional and Pharmacological Activities of Berries

Functional plant-based foods (such as fruits, vegetables, and berries) can improve health, have a preventive effect, and diminish the risk of different chronic diseases during in vivo and in vitro studies. Berries contain many phytochemicals, fibers, vitamins, and minerals. The primary phytochemicals in berry fruits are phenolic compounds including flavonoids (anthocyanins, flavonols, flavones, flavanols, flavanones, and isoflavonoids), tannins, and phenolic acids. Since berries have a high concentration of polyphenols, it is possible to use them for treating various diseases pharmacologically by acting on oxidative stress and inflammation, which are often the leading causes of diabetes, neurological, cardiovascular diseases, and cancer. This review examines commonly consumed berries: blackberries, blackcurrants, blueberries, cranberries, raspberries, black raspberries, and strawberries and their polyphenols as potential medicinal foods (due to the presence of pharmacologically active compounds) in the treatment of diabetes, cardiovascular problems, and other diseases. Moreover, much attention is paid to the bioavailability of active berry components. Hence, this comprehensive review shows that berries and their bioactive compounds possess medicinal properties and have therapeutic potential. Nevertheless, future clinical trials are required to study and improve the bioavailability of berries' phenolic compounds and extend the evidence that the active compounds of berries can be used as medicinal foods against various diseases.

Dietary Fiber Modulates the Fermentation Patterns of Cyanidin-3-O-Glucoside in a Fiber-Type Dependent Manner

The interactions between cell-wall polysaccharides and polyphenols in the gastrointestinal tract have attracted extensive attention. We hypothesized that dietary fiber modulates the fermentation patterns of cyanidin-3-O-glucoside (C3G) in a fiber-type-dependent manner. In the present study, the effects of four dietary fibers (fructose-oligosaccharides, pectin, β-glucan and arabinoxylan) on the modulation of C3G fermentation patterns were investigated through in vitro fermentation inoculated with human feces. The changes in gas volume, pH, total carbohydrate content, metabolites of C3G, antioxidant activity, and microbial community distribution during in vitro fermentation were analyzed. After 24 h of fermentation, the gas volume and total carbohydrate contents of the four dietary-fiber-supplemented groups respectively increased and decreased to varying degrees. The results showed that the C3G metabolites after in vitro fermentation mainly included cyanidin, protocatechuic acid, 2,4,6-trihydroxybenzoic acid, and 2,4,6-trihydroxybenzaldehyde. Supplementation of dietary fibers changed the proportions of C3G metabolites depending on the structures. Dietary fibers increased the production of short-chain fatty acids and the relative abundance of gut microbiota Bifidobacterium and Lactobacillus, thus potentially maintaining colonic health to a certain extent. In conclusion, the used dietary fibers modulate the fermentation patterns of C3G in a fiber-type-dependent manner.

Metabolomics Technologies for the Identification and Quantification of Dietary Phenolic Compound Metabolites: An Overview

In the search for natural products with properties that may protect against or slow down chronic and degenerative diseases (e.g., cancer, and cardiovascular and neurodegenerative conditions), phenolic compounds (PC) with benefits for human health have been identified. The biological effects of PC in vivo depend on their bioavailability, intestinal absorption, metabolism, and interaction with target tissues. The identification of phenolic compounds metabolites (PCM), in biological samples, after food ingestion rich in PC is a first step to understand the overall effect on human health. However, their wide range of physicochemical properties, levels of abundance, and lack of reference standards, renders its identification and quantification a challenging task for existing analytical platforms. The most frequent approaches to metabolomics analysis combine mass spectrometry and NMR, parallel technologies that provide an overview of the metabolome and high-power compound elucidation. In this scenario, the aim of this review is to summarize the pre-analytical separation processes for plasma and urine samples and the technologies applied in quantitative and qualitative analysis of PCM. Additionally, a comparison of targeted and non-targeted approaches is presented, not available in previous reviews, which may be useful for future metabolomics studies of PCM.

Ellagic acid and urolithin A modulate the immune response in LPS-stimulated U937 monocytic cells and THP-1 differentiated macrophages

Dietary polyphenols are subjected, following ingestion, to an extensive metabolism, and the molecules that act at the cellular and tissue level will be, most likely, metabolites rather than native polyphenols. The mechanisms behind the positive effects exerted by polyphenols are not yet completely elucidated, since most in vitro studies use unmetabolised polyphenols rather than the metabolites present in the body. The aim of this study was to investigate and compare the potential effect of phenolic metabolites on the immune response using U937 monocyte and THP-1 macrophage cell cultures. Of the 16 metabolites tested, urolithins (Uro), and Uro A, in particular were the most potent, showing a modest increase in basal NF-κB activity and a reduction in lipopolysaccaride (LPS)-induced NF-κB activity, gene expression and secretion of pro-inflammatory cytokines. Protocatechuic acid and its sulfate/glucuronide metabolites reduced LPS-induced NF-κB activity, but not IL-6 and TNF-α cytokine secretion. Interestingly, both ellagic acid and its metabolite Uro A had immunomodulating effects, although they regulated the immune response differently, and both reduced LPS-induced NF-κB activity in U937 cells. However, while Uro A dramatically reduced IL-6 and IL-10 mRNA expression, no effect could be observed with ellagic acid. In THP-1 cells, treatment with ellagic acid dramatically reduced the expression of Toll-like receptor 4, while Uro A had no effect. The dual role observed for Uro A, showing both a modest increase in basal NF-κB activity and a reduction in LPS-induced NF-κB activity, as well as a reduction in LPS-induced pro-inflammatory cytokine secretion, makes this metabolite particularly interesting for further studies in animals and humans.

Effect of Gut Microbiota Biotransformation on Dietary Tannins and Human Health Implications

Tannins represent a heterogeneous group of high-molecular-weight polyphenols that are ubiquitous among plant families, especially in cereals, as well as in many fruits and vegetables. Hydrolysable and condensed tannins, in addition to phlorotannins from marine algae, are the main classes of these bioactive compounds. Despite their low bioavailability, tannins have many beneficial pharmacological effects, such as anti-inflammatory, antioxidant, antidiabetic, anticancer, and cardioprotective effects. Microbiota-mediated hydrolysis of tannins produces highly bioaccessible metabolites, which have been extensively studied and account for most of the health effects attributed to tannins. This review article summarises the effect of the human microbiota on the metabolism of different tannin groups and the expected health benefits that may be induced by such mutual interactions. Microbial metabolism of tannins yields highly bioaccessible microbial metabolites that account for most of the systemic effects of tannins. This article also uses explainable artificial intelligence to define the molecular signatures of gut-biotransformed tannin metabolites that are correlated with chemical and biological activity. An understanding of microbiota-tannin interactions, tannin metabolism-related phenotypes (metabotypes) and chemical tannin-metabolites motifs is of great importance for harnessing the biological effects of tannins for drug discovery and other health benefits.

Phenolic Metabolites in the Urine and Plasma of Healthy Men After Acute Intake of Purple Potato Extract Rich in Methoxysubstituted Monoacylated Anthocyanins

SCOPE

Structurally stable acylated anthocyanins have potential in various food applications but the effects of acylation and methoxysubstitution on anthocyanin metabolism are poorly understood. This is the first study thoroughly investigating phenolic metabolites, their time-wise changes, and pharmacokinetics following an acute intake of methoxysubstituted monoacylated anthocyanins.

METHODS AND RESULTS

Healthy male volunteers (n = 17) consumed a yellow potato meal with and without purple potato extract rich in acylated anthocyanins (152 mg) and hydroxycinnamic acid conjugates (140 mg). Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is used for identification and quantification of metabolites from serially collected urine and plasma. While the parent anthocyanins are not detected, 28 phenolic metabolites from urine and 14 from plasma are quantified, including hydroxybenzoic and hydroxycinnamic acids and protocatechuic acid sulfates and glucuronides; three (catechol, gallic acid-4-O-glucuronide, and 2-methoxybenzoic acid) are detected for the first time after anthocyanin-rich food. Urinary hippuric acid is the most abundant with an increase of 139 µM mM^-1 creatinine after the treatment. A large additional set of tentatively identified phenolic metabolites are detected. Late urinary peak time values suggest colonic degradation.

CONCLUSION

Acylated anthocyanins are more bioavailable than earlier reported after extensive degradation in human and/or colonial metabolism to phenolic metabolites, which may be further conjugated and demethylated.

Sweetener influences plasma concentration of flavonoids in humans after an acute intake of a new (poly)phenol-rich beverage

BACKGROUND AND AIM

The overconsumption of sucrose is closely related to sugar-sweetened beverages and one of the main factors associated with the increase of metabolic diseases, such as type 2 diabetes, obesity, and insulin resistance. So, the addition of alternative sweeteners to new fruit-based drinks could contribute to minimizing the incidence or severity of these pathologies. Nevertheless, current knowledge on the influence of these additives on the bioactive compounds present in these beverages is still scarce.new-onset hypertension, but few data were published in Asian. We aimed to investigate the association of lipid profiles with new-onset hypertension in a Chinese community-based non-hypertensive cohort without lipid-lowering treatment (n = 1802).

METHODS AND RESULTS

Hence, to contribute to the understanding of this issue, the plasma concentration of phenolic compounds (anthocyanins and flavanones), after the ingestion of a new maqui-citrus-based beverage, supplemented with sucrose (natural high caloric), stevia (natural non-caloric), or sucralose (artificial non-caloric), was evaluated as evidence of their intestinal absorption and metabolism previous to renal excretion. The beverages were ingested by volunteers (n = 20) and the resulting phenolic metabolites in plasma were analyzed by UHPLC-ESI-MS/MS. A total of 13 metabolites were detected: caffeic acid sulfate, caffeic acid glucuronide, 3,4-dihydroxyfenylacetic, 3,4-dihydroxyfenylacetic sulfate. 3,4-dihydroxyfenylacetic acid di-sulfate, 3,4-dihydroxyfenylacetic di-glucuronide, 3,4-dihydroxyfenylacetic glucuronide-sulfate, trans-ferulic acid glucuronide, naringenin glucuronide, vanillic acid, vanillic acid sulfate, vanillic acid glucuronide-sulfate, and vanillic acid di-glucuronide, being recorded their maximum concentration after 30-60 min.

CONCLUSION

In general, sucralose provided the greatest absorption value for most of these metabolites, followed by stevia. Due to this, the present study proposes sucralose and stevia (non-caloric sweeteners) as valuable alternatives to sucrose (high caloric sweetener), to avoid the augmented risk of several metabolic disorders.

Characterization of carotenoids and phenolics during fruit ripening of Chinese raspberry (Rubus chingii Hu)

Chinese raspberry (Rubus chingii Hu) is a fruit valued for it's health benefits, which is indigenous to China. It is a great source of antioxidants. However, the fruit phytochemicals are poorly understood. Phenolics and carotenoids attract much attention for their antioxidant capability, and they dramatically change during fruit ripening, leading to the difference in color, flavor and medicinal components. In this study, we investigated the change of carotenoids, phenolics and antioxidant activity using spectrophotometry during four different ripening phases i.e. mature green (MG), green yellow (GY), yellow orange (YO) and red (RE). The major components of carotenoids, anthocyanins, ellagitannins and flavonols were identified and quantified by LC-MS/MS. As a result, five carotenoids (mainly β-Citraurin and its esters), six anthocyanins (mainly anthocyanins covalently linked to another flavonoid unit), methyl (S)-flavogallonate and rourinoside were first identified in Rubus. In contrast to other known raspberries, R. chingii had a continuous decrease in total phenolics during fruit ripening, which was due to a continuous decrease in flavonoids (including anthocyanin). Total anthocyanin and flavonoid respectively declined from 19.5 to 6.9 mg/100 g FW, and 646.2 to 128.5 mg/100 g FW during fruit maturation and coloration. Accordingly, the components of anthocyanins, ellagitannins and flavonols also declined, thus resulting in a decrease in antioxidant activity (from 41.2 to 10.1 TEAC/100 g FW in ABTS and from 35.3 to 7.7 mmol TEAC/100 g FW in FRAP). In contrast, total carotenoid increased from 184.2 to 305.4 mg/100 g FW. Accordingly, the components of carotenoids also increased, with the exception of lutein. Additionally, kaempferol and quercetin were the main flavonoid aglycones, which were linked to a variety of glycosides. These kaempferol- and quercetin-glycosides mainly accumulated in epidermal hair and placentae. Notably, carotenoids (i.e. β-citraurin esters), instead of anthocyanins, gradually accumulated during fruit ripening, imparting the reddish color to ripe fruit.

Antioxidant Activity and Bio-Accessibility of Polyphenols in Black Carrot (Daucus carota L. ssp. sativus var. atrorubens Alef.) and Two Derived Products during Simulated Gastrointestinal Digestion and Colonic Fermentation

Black carrot has been attracting increasing thanks to its high bioactive compound content. This study presents the polyphenol bio-accessibility of black carrot and two derived products (black carrot snack (BC snack) and black carrot seasoning (BC seasoning)) after in vitro gastrointestinal digestion and colonic fermentation. Additionally, antioxidant activity was measured by 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Nine flavonoids and eight anthocyanins were determined by ultra high-performance liquid chromatography high resolution mass spectrometry (UHPLC-HRMS) analysis, the predominant compounds being the hydroxycinnamic acids 3-O-feruloylquinic acid, 4-O-feruloylquinic acid and chlorogenic acid. The BC snack (108 µmol/g DW) presented the highest total polyphenol content, followed by BC seasoning (53 µmol/g DW) and black carrot (11.4 µmol/g DW). The main polyphenols still bio-accessible after in vitro digestion were the hydroxycinnamic acids, with mean recovery rates of 113 % for black carrot, 69% for BC snack and 81% for BC seasoning. The incubation of black carrot and its derived products with human faecal bacterial resulted in the complete degradation of anthocyanins and in the formation of mainly 3-(4′-hydroxyphenyl)propanoic acid as the major catabolic event. In conclusion, our results suggest that the black carrot matrix impacts significantly affects the bio-accessibility of polyphenols and, therefore, their potential health benefits.

Extracts of Digested Berries Increase the Survival of Saccharomyces cerevisiae during H2O2 Induced Oxidative Stress

Many studies suggest anthocyanins may prevent the development of several diseases. However, anthocyanin bioactivity against cellular stress is not fully understood. This study aimed to evaluate the protective effect of berry anthocyanins on stressed cells using Saccharomyces cerevisiae. The impact of in vitro gastrointestinal digestion on anthocyanin profiles was also assessed. Bilberry and blackcurrant had higher anthocyanin levels than raspberry and strawberry, but digestion reduced the detected anthocyanins by approximately 90%. Yeast cells with and without digested or nondigested anthocyanin extracts were exposed to H₂O₂ and examined for survival. In the presence of anthocyanins, particularly from digested strawberry, a significant increase in cell survival was observed, suggesting that the type and levels of anthocyanins are important factors, but they also need to undergo gastrointestinal (GI) structural modifications to induce cell defence. Results also showed that cells need to be exposed to anthocyanins before the stress was applied, suggesting induction of a cellular defence system by anthocyanins or their derivatives rather than by a direct antioxidative effect on H₂O₂. Overall, data showed that exposure of severely stressed yeast cells to digested berry extracts improved cell survival. The findings also showed the importance of considering gastrointestinal digestion when evaluating anthocyanins’ biological activity.

High-Throughput Screening and Characterization of Phenolic Compounds in Stone Fruits Waste by LC-ESI-QTOF-MS/MS and Their Potential Antioxidant Activities

Stone fruits, including peach (Prunus persica L.), nectarine (Prunus nucipersica L.), plum (Prunus domestica L.) and apricot (Prunus armeniaca L.) are common commercial fruits in the market. However, a huge amount of stone fruits waste is produced throughout the food supply chain during picking, handling, processing, packaging, storage, transportation, retailing and final consumption. These stone fruits waste contain high phenolic content which are the main contributors to the antioxidant potential and associated health benefits. The antioxidant results showed that plum waste contained higher concentrations of total phenolic content (TPC) (0.94 ± 0.07 mg gallic acid equivalents (GAE)/g) and total flavonoid content (TFC) (0.34 ± 0.01 mg quercetin equivalents (QE)/g), while apricot waste contained a higher concentration of total tannin content (TTC) (0.19 ± 0.03 mg catechin equivalents (CE)/g) and DPPH activity (1.47 ± 0.12 mg ascorbic acid equivalents (AAE)/g). However, nectarine waste had higher antioxidant capacity in ferric reducing-antioxidant power (FRAP) (0.98 ± 0.02 mg AAE/g) and total antioxidant capacity (TAC) (0.91 ± 0.09 mg AAE/g) assays, while peach waste showed higher antioxidant capacity in 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay (0.43 ± 0.09 mg AAE/g) as compared to other stone fruits waste. Qualitative and quantitative phenolic analysis of Australian grown stone fruits waste were conducted by liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) and HPLC-photodiode array detection (PDA). The LC-ESI-QTOF-MS/MS result indicates that 59 phenolic compounds were tentatively characterized in peach (33 compounds), nectarine (28), plum (38) and apricot (23). The HPLC-PDA indicated that p-hydroxybenzoic acid (18.64 ± 1.30 mg/g) was detected to be the most dominant phenolic acid and quercetin (19.68 ± 1.38 mg/g) was the most significant flavonoid in stone fruits waste. Hence, it could be concluded that stone fruit waste contains various phenolic compounds and have antioxidant potential. The results could support the applications of these stone fruit wastes in other food, feed, nutraceutical and pharmaceutical industries.

Beverages Based on Second Quality Citrus Fruits and Maqui Berry, a Source of Bioactive (Poly)phenols: Sorting Out Urine Metabolites upon a Longitudinal Study

The intake of sugar-sweetened beverages has been associated with an augmented prevalence of metabolic diseases, namely, obesity, type II diabetes, and metabolic syndrome. On the other hand, nowadays, it is broadly accepted that foods and beverages rich in (poly)phenols could contribute to reducing the incidence of these pathologies. In this sense, the objective of the work was to revalue second quality citrus fruits for the development of new beverages, rich in anthocyanins and flavanones (maqui berry and second qualities citrus-based), and evaluate the influence of alternative sweeteners (sucralose, sucrose, or stevia), regarding the bioaccessibility and bioavailability of these bioactive compounds in the frame of a chronic (longitudinal) intervention. To fulfill this objective, a longitudinal study of the urinary excretion of anthocyanins and flavanones, after 2-months of ingestion of the developed maqui-citrus beverage, by 138 volunteers (n = 46 per beverage) and the analysis of the resulting phenolic metabolites by ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-ESI-QqQ-MS/MS) was carried out. As major results, the bioavailable metabolites of caffeic acid (CA), catechol (CAT), 3,4-di-hydroxyphenylacetic acid (DHPAA), eriodictyol (E), homoeriodictyol (HE), hippuric acid (HA), naringenin (N), trans-ferulic acid (TFA), 2,4,6-tri-hydroxybenzaldehyde (THBA), trans-isoferulic acid (TIFA), and vanillic acid (VA) were detected. Accordingly, significantly different bioavailability was dependent on the sweetener used, allowing proposing stevia and, to a lower extent, sucralose, as valuable alternatives to sucrose.

A Comparative Investigation on Phenolic Composition, Characterization and Antioxidant Potentials of Five Different Australian Grown Pear Varieties

Pear (Pyrus communis L.) is widely spread throughout the temperate regions of the world, such as China, America and Australia. This fruit is popular among consumers due to its excellent taste and perceived health benefits. Various bioactive compounds, which contribute to these health benefits, have been detected in the pear fruits, including a range of phenolic compounds. Five Australian grown pear varieties, which include Packham’s Triumph, Josephine de Malines, Beurre Bosc, Winter Nelis and Rico were selected for this study to examine the phenolic compounds in pears. Beurre Bosc exhibited the highest total polyphenol content (TPC) (3.14 ± 0.02 mg GAE/g), total tannin content (TTC) (1.43 ± 0.04 mg CE/g) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) (5.72 ± 0.11 mg AAE/g), while the Josephine de Malines variety was high in total flavonoid content (TFC) (1.53 ± 0.09 mg QE/g), ferric reducing antioxidant power (FRAP) (4.37 ± 0.04 mg AAE/g), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (4.44 ± 0.01 mg AAE/g) and total antioxidant capacity (TAC) (5.29 ± 0.09 mg AAE/g). The liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) data indicate that a total of 73 phenolic compounds were detected in Beurre Bosc (37 compounds), Josephine de Malines (34), Rico (22), Packham’s Triumph (15) and Winter Nelis (9), respectively. From HPLC-PDA quantification, the Beurre Bosc pear variety showed significantly higher in phenolic acids (chlorogenic acid; 17.58 ± 0.88 mg/g) and while flavonoids were significantly higher in Josephine de Malines (catechin; 17.45 ± 1.39 mg/g), as compared to other pear varieties. The analyses suggest that the Australian grown pears might contain an ideal source of phenolic compounds which benefit human health. The information provided by the present work can serve as practical supporting data for the use of pears in the nutraceutical, pharmaceutical and food industries.

Ex vivo fecal fermentation of human ileal fluid collected after raspberry consumption modifies (poly)phenolics and modulates genoprotective effects in colonic epithelial cells

Diets rich in fruit and vegetables are associated with a decreased incidence of colorectal cancer (CRC) due, in part, to the bioactive (poly)phenolic components and their microbiota-mediated metabolites. This study investigated how such compounds, derived from ingested raspberries in the gastrointestinal tract, may exert protective effects by reducing DNA damage. Ileal fluids collected pre- and post-consumption of 300 g of raspberries by ileostomists (n = 11) were subjected to 24 h ex vivo fermentation with fecal inoculum to simulate interaction with colonic microbiota. The impact of fermentation on (poly)phenolics in ileal fluid was determined and the bioactivity of ileal fluids pre- and post fermentation investigated. (Poly)phenolic compounds including sanguiin H-6, sanguiin H-10 and cyanidin-3-O-sophoroside decreased significantly during fermentation while, in contrast, microbial catabolites, including 3-(3′-hydroxyphenyl)propanoic acid, 3-hydroxybenzoic acid and benzoic acid increased significantly. The post-raspberry ileal fermentate from 9 of the 11 ileostomates significantly decreased DNA damage (~30%) in the CCD 841 CoN normal cell line using an oxidative challenge COMET assay. The raspberry ileal fermentates also modulated gene expression of the nuclear factor 2–antioxidant responsive element (Nrf2-ARE) pathway involved in oxidative stress cytoprotection, namely Nrf2, NAD(P)H dehydrogenase, quinone-1 and heme oxygenase-1. Four of the phenolic catabolites were assessed individually, each significantly reducing DNA damage from an oxidative challenge over a physiologically relevant 10–100 μM range. They also induced a differential pattern of expression of key genes in the Nrf2-ARE pathway in CCD 841 CoN cells. The study indicates that the colon-available raspberry (poly)phenols and their microbial-derived catabolites may play a role in protection against CRC in vivo.

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Health effects of dietary (poly)phenols linked to interactions within the GI tract.

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Ileostomy-based bioavailability studies allow effective interrogation of the GI tract.

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Fecal fermentation of raspberry-enriched ileal fluid, increases phenolic content.

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Raspberry ileal fluid fermentates & phenolic acids reduce DNA damage in colonocytes.

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Cytoprotective Nrf2-ARE pathway modulated by ileal fluid fermentates & phenolic acids.

Health promoting properties and sensory characteristics of phytochemicals in berries and leaves of sea buckthorn (Hippophaë rhamnoides)

Sea buckthorn (Hippophaë rhamnoides L., SB), as a multi-functional plant, is widely grown in Asia, Europe and Canada. The berries and leaves of SB contain a diverse array of health-supporting phytochemicals, which are also related to the sensory qualities of berry and berry products. This review summarizes the biologically active key-compounds of the berries and leaves of SB, their health-promoting effects, as well as the contributions to the sensory quality of the berries. The target compounds consist of sugars, sugar derivatives, organic acids, phenolic compounds and lipophilic compounds (mainly carotenoids and tocopherols), which play an important role in anti-inflammatory and antioxidant functions, as well as in metabolic health. In addition, these compounds contribute to the orosensory qualities of SB berries, which are closely related to consumer acceptance and preference of the products. Studies regarding the bioavailability of the compounds and the influence of the processing conditions are also part of this review. Finally, the role of the sensory properties is emphasized in the development of SB products to increase utilization of the berry as a common meal component and to obtain value-added products to support human health.

Chokeberry anthocyanins and their metabolites ability to cross the blood-cerebrospinal fluid barrier

The aim of this study was to determine whether anthocyanins and their phase II metabolites permeate the blood-cerebrospinal fluid barrier (B-CSF-B) of sheep and to profile these compounds in sheep biofluids after chokeberry intraruminal administration. Anthocyanins were analyzed using micro-HPLC-MS/MS. After chokeberry administration, anthocyanins were absorbed and occurred in body fluids mainly in the form of methylated, glucuronidated, and sulfated derivatives (in total, 21 derivatives were identified). The study showed that anthocyanins penetrated the B-CSF-B and their change in profile and concentration in the cerebrospinal fluid (CSF) resulted from fluctuations in concentrations of these compounds in blood plasma, although the presence of various cyanidin derivatives in CSF also depended on their chemical structure. The biological fate of chokeberry anthocyanins, from absorption into blood to penetration into CSF, was tracked to facilitate the design of further experimental procedures to determine the biological properties of these compounds, including potentially neuroprotective activities.

Functional Deficits in Gut Microbiome of Young and Middle-Aged Adults with Prediabetes Apparent in Metabolizing Bioactive (Poly)phenols

Background: Gut microbiota metabolize select dietary (poly)phenols to absorbable metabolites that exert biological effects important in metabolic health. Microbiota composition associated with health/disease status may affect its functional capacity to yield bioactive metabolites from dietary sources. Therefore, this study assessed gut microbiome composition and its related functional capacity to metabolize fruit (poly)phenols in individuals with prediabetes and insulin resistance (PreDM-IR, n = 26) compared to a metabolically healthy Reference group (n = 10). Methods: Shotgun sequencing was used to characterize gut microbiome composition. Targeted quantitative metabolomic analyses of plasma and urine collected over 24 h were used to assess microbial-derived metabolites in response to a (poly)phenol-rich raspberry test drink. Results: PreDM-IR compared to the Reference group: (1) enriched Blautia obeum and Blautia wexlerae and depleted Bacteroides dorei and Coprococcus eutactus. Akkermansia muciniphila and Bacteroides spp. were depleted in the lean PreDM-IR subset; and (2) impaired microbial catabolism of select (poly)phenols resulting in lower 3,8-dihydroxy-urolithin (urolithin A), phenyl-γ-valerolactones and various phenolic acids concentrations (p < 0.05). Controlling for obesity revealed relationships with microbial species that may serve as metagenomic markers of diabetes development and therapeutic targets. Conclusions: Data provide insight from multi-omics approaches to advance knowledge at the diet–gut–disease nexus serving as a platform for devising dietary strategies to improve metabolic health.

Comparative dietary sulfated metabolome analysis reveals unknown metabolic interactions of the gut microbiome and the human host

The gut microbiome converts dietary compounds that are absorbed in the gastrointestinal tract and further metabolized by the human host. Sulfated metabolites are a major compound class derived from this co-metabolism and have been linked to disease development. In the present multidisciplinary study, we have investigated human urine samples from a dietary intervention study with 22 individuals collected before and after consumption of a polyphenol rich breakfast. These samples were analyzed utilizing our method combining enzymatic metabolite hydrolysis using an arylsulfatase and mass spectrometric metabolomics. Key to this study is the validation of 235 structurally diverse sulfated metabolites. We have identified 48 significantly upregulated metabolites upon dietary intervention including 11 previously unknown sulfated metabolites for this diet. We observed a large variation in subjects based on their potential to sulfate metabolites, which may be the foundation for classification of subjects as high and low sulfate metabolizers in future large cohort studies. The reported sulfatase-based method is a robust tool for the discovery of unknown microbiota-derived metabolites in human samples.

Plasma and Urinary (Poly)phenolic Profiles after 4-Week Red Raspberry (Rubus idaeus L.) Intake with or without Fructo-Oligosaccharide Supplementation

Red raspberries (RRB) are high in anthocyanin- and ellagitannin- type (poly)phenols. This study aimed to investigate the effect of 4-week RRB supplementation on (poly)phenolic metabolism in adults with prediabetes and insulin-resistance (PreDM-IR); and whether adding fructo-oligosaccharides (FOS), prebiotics, would augment the microbial metabolites of RRB (poly)phenols. In a randomized crossover clinical trial, subjects (n = 35: PreDM-IR, n = 25; healthy Reference group, n = 10) consumed 1 cup RRB (fresh weight equivalence) per day and RRB with 8 g FOS per day each for 4 weeks in random order separated by 4-week washout. Plasma and urinary (poly)phenolic metabolites were characterized after (0–24 h) consuming a RRB-based test drink (2 cups RRB) at baseline/week 0 and again after 4-week supplementations. A total of 123 (poly)phenolic metabolites were quantified. After 4-week RRB supplementation, several metabolite groups were significantly increased (p < 0.05), including urolithins, phenyl-γ-valerolactones, and phenolic acids. Supplementing FOS with RRB for 4 weeks enhanced benzoic acid derivatives compared to the baseline (p < 0.05). Specific effects of supplementation by metabolic status indicated 4-week RRB supplementation significantly increased microbial metabolites that were lower in PreDM-IR group. Our results suggest alterations in the capacity of PreDM-IR group to metabolize and render bioavailable raspberry-derived (poly)phenols when consumed regularly.

Absorption, metabolism, and excretion of orange juice (poly)phenols in humans: The effect of a controlled alcoholic fermentation

The consumption of orange juice provides high concentrations of health-promoting bioactive compounds, the amount of which may increase upon alcoholic fermentation. Although fermentation may offer new prospects for the industry of orange-related products, there is a lack of studies reporting the influence of controlled alcoholic fermentation on the bioavailability of orange juice (poly)phenols in humans. The aim of this study was to evaluate the absorption profile, pharmacokinetic parameters, and urinary excretion of orange juice (poly)phenols in nine volunteers after acute administration of an orange juice and a beverage prepared after controlled alcoholic fermentation of the juice. Plasma and urine samples were analysed through a UHPLC-ESI-MS/MS targeted approach. A total of 24 (poly)phenol metabolites including both flavanone and phenolic acid derivatives were quantified, most of them being recorded only in urine. Phase II conjugates of hesperetin and naringenin were the main metabolites in plasma, while phenolic acids, in particular hydroxybenzoic acids, were the main compounds in urine. (Poly)phenols in both beverages were highly bioavailable (between 46 and 59%) and a notable inter-individual variability was seen. Significant treatment × time interactions were recorded for the sum of flavanones and phenolic acids in plasma, the (poly)phenols in the fermented juice being absorbed faster than after orange juice intake. Nevertheless, despite the food matrix having an impact on the absorption profile of orange juice (poly)phenols, this did not influence the pharmacokinetic parameters and urinary excretion of the (poly)phenol metabolites.

Berry polyphenols metabolism and impact on human gut microbiota and health

Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The products of their metabolization, however, may be the most bioactive compounds due to their ability to enter the blood circulation and reach the organs. The main site of metabolization of the complex polyphenols to smaller phenolic compounds is the gut through the action of microorganisms, and reciprocally polyphenols and their metabolites can also modulate the microbial populations. In healthy subjects, these modulations generally lead to an increase in Bifidobacterium, Lactobacillus and Akkermansia, therefore suggesting a prebiotic-like effect of the berries or their compounds. Finally, berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis. This review recapitulates the knowledge available on the interactions between berries polyphenols, gut microbiota and gut health and identifies knowledge gaps for future research.

Food intake biomarkers for berries and grapes

Grapes and berries are two types of widely consumed fruits characterized by a high content in different phytochemicals. However, their accurate dietary assessment is particularly arduous, because of the already wide recognized bias associated with self-reporting methods, combined with the large range of species and cultivars and the fact that these fruits are popularly consumed not only in fresh and frozen forms but also as processed and derived products, including dried and canned fruits, beverages, jams, and jellies. Reporting precise type and/or quantity of grape and berries in FFQ or diaries can obviously be affected by errors. Recently, biomarkers of food intake (BFIs) rose as a promising tool to provide accurate information indicating consumption of certain food items. Protocols for performing systematic reviews in this field, as well as for assessing the validity of candidate BFIs have been developed within the Food Biomarker Alliance (FoodBAll) Project. This paper aims to evaluate the putative BIFs for blueberries, strawberries, raspberries, blackberries, cranberries, blackcurrant, and grapes. Candidate BFIs for grapes were resveratrol metabolites and tartaric acid. The metabolites considered as putative BFI for berries consumption were mostly anthocyanins derivatives together with several metabolites of ellagitannins and some aroma compounds. However, identification of BFIs for single berry types encountered more difficulties. In the absence of highly specific metabolites reported to date, we suggested some multi-metabolite panels that may be further investigated as putative biomarkers for some berry fruits.

Cyanidin-3-glucoside as a possible biomarker of anthocyanin-rich berry intake in body fluids of healthy humans: a systematic review of clinical trials

Context

Anthocyanins are phenolic compounds found in berries. They exhibit promising health benefits in humans, but no accurate biomarkers of berry intake have been identified thus far.

Objective

The aim of this systematic review is to propose a biomarker of anthocyanin-rich berry intake in human plasma and urine.

Data Sources

PubMed and Cochrane databases were searched from January 2008 to January 2019.

Study Selection

Databases were searched for human intervention studies that assessed the presence of anthocyanins in human body fluids using high-throughput techniques. Non-English articles and studies publishing targeted analyses were excluded.

Data Extraction

Ten clinical trials, in which 203 phenolic compounds were identified, were included and assessed qualitatively. The following criteria were used to identify biomarkers of berry intake: frequency, plausibility, dose-response, time response, robustness, reliability, stability, analytical performance, and reproducibility. Sensitivity and specificity of potential biomarkers were determined by the receiver operating characteristic curve.

Results

Of the 203 phenolic compounds identified in human samples, the anthocyanin cyanidin-3-glucoside was the molecule found most frequently in urine (58.06%) and plasma (69.49%). Cyanidin-3-glucoside fulfills the essential criterion of plausibility as well as the dose-response, time response, stability, and analytical performance criteria. Its positive predictive value is 74% (P = 0.210) in plasma, which is acceptable, and 61.7% (P = 0.402) in urine.

Conclusions

Current evidence suggests that cyanidin-3-glucoside is a potential biomarker of anthocyanin-rich berry intake in plasma and urine of healthy humans.

PROSPERO registration number

CRD42018096796.

Ellagic Acid-Derived Urolithins as Modulators of Oxidative Stress

Oxidative stress is a state of excess of prooxidative species relative to the antioxidant defenses (enzymatic and nonenzymatic) in a living organism. The consequence of this imbalance is damage of the major cellular macromolecules (carbohydrates, lipids, proteins, and DNA), which further leads to a gradual loss of tissue and organ function. It has been shown that oxidative stress plays an important role in the pathogenesis of many chronic diseases (cardiovascular, metabolic, and neurodegenerative diseases and cancer) and in the process of aging. Thus, many strategies to combat oxidative stress have been proposed and tested. In this context, food rich in antioxidants has received great attention. Pomegranate, berries, and walnuts have been recognized as “superfood” particularly for their cardioprotective effects. The common characteristic of these foods is the high content of ellagitannins. Since tannins are not bioavailable, they have been neglected in nutrition science and even considered antinutrients for a long time. However, this view has changed dramatically once it was recognized that ellagic acid, released from ellagitannins in the gastrointestinal system, is further metabolized by colonic microbiota to bioavailable compounds—known as urolithins. Thus, urolithins (3,4-benzocoumarin derivatives) have emerged as novel natural bioactive compounds and are now the focus of extensive investigations. So far, urolithins were shown to be powerful modulators of oxidative stress and agents with potential anti-inflammatory, antiproliferative, and antiaging properties. Furthermore, a few synthetic derivatives of urolithins were recognized as lead compounds for new drug development. Available data on urolithin synthesis, physicochemical and pharmacokinetic characteristics, biological activity, and safety will be presented in this review.

New insights into red plant pigments: more than just natural colorants

Pigments make nature both colorful and attractive. Humans have always incorporated the natural pigments of fruits, vegetables and spices into their dietary requirements. Naturally occurring red pigments in plants are carotenoids, anthocyanins and betacyanins. Natural pigments, apart from colour, provide added properties and are therefore considered to be bioactive constituents. Red natural colorants are one of the most widely used in the food industry. The interest in these pigments lies in the enhancement of the healthy effects of the diet. In this context, attention is given to carotenoids, anthocyanins and betacyanins, with emphasis on the basic chemical and biochemical attributes and wide-ranging health-promoting benefits of these pigments. Thus, in this review, we systematically present the advantages and limitations of these natural pigments as food colorants in relation to their physico-chemical properties, reactivity and bioactivity.

Increasing Doses of Blueberry Polyphenols Alters Colonic Metabolism and Calcium Absorption in Ovariectomized Rats

SCOPE

Blueberries are rich sources of bioactive polyphenols that may provide health benefits when consumed regularly, leading to their increased marketing as dietary supplements. However, the metabolic changes associated with consuming concentrated doses of purified polyphenols, as may be present in dietary supplements, are unknown, especially when considering the colonic metabolites formed. This study aimed to evaluate the pharmacokinetics of high doses of purified blueberry polyphenols.

METHODS AND RESULTS

5-month old, ovariectomized Sprague-Dawley rats are acutely dosed with purified blueberry polyphenols (0, 75, 350, and 1000 mg total polyphenols per kg body weight (bw)) and 45 Ca to measure calcium absorption. Blood and urine are collected for 48 h after dosing and phenolic metabolites measured via ultra high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The most prominent metabolites are colonically generated cinnamic and hippuric acids. Smaller amounts of other phenolic acids, flavonols, and anthocyanins are also detected. Most metabolites follow a dose-response relationship, though several show saturated absorption. Maximal metabolite concentrations are reached within 12 h for a majority of compounds measured, while some (e.g., hippuric acid) peaked up to 24 h post-dosing. Calcium absorption is significantly increased in the highest dose group (p = 0.03).

CONCLUSION

These results indicate that increased doses of blueberry polyphenols induce changes in intestinal phenolic metabolism and increase calcium absorption.

State of the Art of Anthocyanins: Antioxidant Activity, Sources, Bioavailability, and Therapeutic Effect in Human Health

The antioxidant activity of anthocyanins in food is well known. Numerous antioxidant assays have been proposed to measure the capacity of anthocyanins to prevent the oxidation process that naturally occurs. Different solvents, temperatures, and pH levels are applied in each assay, and these factors should be taken into account in order to obtain useful and reproducible results. The concentration and the structure of these compounds are directly related to their antioxidant capacity and their environment. However, the effectiveness of the anthocyanin ingestion against diseases is also influenced by its bioavailability. Novel methodologies that simulate the digestion process have been developed in order to facilitate the current knowledge of anthocyanins bioavailability. Studies highlight the potential synergy effect between parent compounds and their derivatives (metabolites, conjugated products, and microbe-generated metabolites). The aim of this review is to provide an overview of advantages and disadvantages of the most common methods to determine the antioxidant activity of anthocyanins, chemical structure, and concentration of these compounds in different edible fruits, vegetables, and plants; their bioavailability after intake; as well as the main therapeutic effect described in the scientific literature.

Constituents and Metabolites of a French Oak Wood Extract (Robuvit®) in Serum and Blood Cell Samples of Women Undergoing Hysterectomy

Ellagitannins are signature constituents of oak wood and their consumption has been associated with various health benefits. In vivo, they undergo metabolic degradation including gut microbial metabolism yielding urolithins. Only limited data is available about compounds being present in blood after intake of an extract from French oak wood, Robuvit®. In the course of a randomized, double-blind, controlled clinical investigation, 66 patients undergoing hysterectomy received placebo or 300 mg Robuvit® per day before and over 8 weeks after surgery. Serum and blood cell samples were analyzed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The number of urolithin producers and the urolithin levels increased after intake of Robuvit®. In serum samples, the median concentration of urolithin A was 14.0 ng/ml [interquartile range (IQR) 57.4] after 8 weeks. Urolithin B was determined at 22.3 ng/ml (IQR 12.6), urolithin C at 2.66 ng/ml (IQR 2.08). In blood cells, lower concentrations and only urolithins A and B were detected. A statistically significant association of lower post-surgical pain scores with metabotype A was detected (p < 0.05). To conclude, supplementation with French oak wood extract raised urolithin generation in patients and suggested health advantages for urolithin-producers.

Differential Catabolism of an Anthocyanin-Rich Elderberry Extract by Three Gut Microbiota Bacterial Species

Elderberries are good sources of anthocyanins, which are poorly absorbed in the upper gastrointestinal tract but extensively transformed into phenolic metabolites at the colonic level. Because different gut microbiota strains have different metabolism, the catabolism of anthocyanins may lead to interindividual differences in metabolite production. In this work, an anthocyanin-rich elderberry extract was incubated with three single gut microbial strains (Enterobacter cancerogenous, Bifidobacterium dentium, and Dorea longicatena) up to 4 days, to assess differences in their phenolic metabolism. All of the strains degraded the elderberry anthocyanins, but the metabolic pathways followed were different. Although some metabolites were common for all of the strains, a wide disparity was observed in the kind and amount of several phenolic metabolites produced by each species. These in vitro preliminary results may be of help in the interpretation of the bioavailability of anthocyanins and give a clue to understand interindividual variability in metabolite production.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Anthocyanin Metabolites in Human Urine after the Intake of New Functional Beverages

Sugar intake abuse is directly related with the increase of metabolic diseases such as type 2 diabetes, obesity, and insulin resistance. Along this line, the development of new beverages using alternative sweeteners could help with combatting the pathophysiological disorders associated to the consumption of sugar. To provide evidence on this issue, in the present work, the bioavailability of anthocyanins was evaluated after the acute ingestion of a new maqui-citrus-based functional beverage rich in polyphenols, and supplemented with a range of sweeteners including sucrose (natural high caloric), stevia (natural non-caloric), and sucralose (artificial non-caloric), as an approach that would allow reducing the intake of sugars while providing bioactive phenolic compounds (anthocyanins). This approach allowed the evaluation of the maximum absorption and the diversity of metabolites excreted through urine. The beverages created were ingested by volunteers (n = 20) and the resulting anthocyanin metabolites in their urine were analyzed by UHPLC-ESI-MS/MS. A total of 29 degradation metabolites were detected: Caffeic acid, catechol, 3,4-dihidroxifenilacetic acid, hippuric acid, trans-ferulic acid, 2,4,6-trihydroxybenzaldehyde, trans-isoferulic acid, and vanillic acid derivatives, where peak concentrations were attained at 3.5 h after beverage intake. Sucralose was the sweetener that provided a higher bioavailability for most compounds, followed by stevia. Sucrose did not provide a remarkably higher bioavailability of any compounds in comparison with sucralose or stevia. The results propose two sweetener alternatives (sucralose and stevia) to sucrose, an overused high calorie sweetener that promotes some metabolic diseases.

Dietary Polyphenols and Gene Expression in Molecular Pathways Associated with Type 2 Diabetes Mellitus: A Review

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder with various contributing factors including genetics, epigenetics, environment and lifestyle such as diet. The hallmarks of T2DM are insulin deficiency (also referred to as β-cell dysfunction) and insulin resistance. Robust evidence suggests that the major mechanism driving impaired β-cell function and insulin signalling is through the action of intracellular reactive oxygen species (ROS)-induced stress. Chronic high blood glucose (hyperglycaemia) and hyperlipidaemia appear to be the primary activators of these pathways. Reactive oxygen species can disrupt intracellular signalling pathways, thereby dysregulating the expression of genes associated with insulin secretion and signalling. Plant-based diets, containing phenolic compounds, have been shown to exhibit remedial benefits by ameliorating insulin secretion and insulin resistance. The literature also provides evidence that polyphenol-rich diets can modulate the expression of genes involved in insulin secretion, insulin signalling, and liver gluconeogenesis pathways. However, whether various polyphenols and phenolic compounds can target specific cellular signalling pathways involved in the pathogenesis of T2DM has not been elucidated. This review aims to evaluate the modulating effects of various polyphenols and phenolic compounds on genes involved in cellular signalling pathways (both in vitro and in vivo from human, animal and cell models) leading to the pathogenesis of T2DM.

A Review of Factors Affecting Anthocyanin Bioavailability: Possible Implications for the Inter-Individual Variability

Anthocyanins are dietary bioactive compounds showing a range of beneficial effects against cardiovascular, neurological, and eye conditions. However, there is, as for other bioactive compounds in food, a high inter and intra-individual variation in the response to anthocyanin intake that in many cases leads to contradictory results in human trials. This variability could be caused at two levels, one at the bioavailability level and the other at the effect and mechanisms of action. In this context, we have thoroughly reviewed the scientific literature on anthocyanins variability caused by variation in bioavailability. Based on the literature reviewed, we have concluded that the variability in anthocyanins bioavailability might be produced by the lack of homogeneity introduced at three different levels: food matrix and food processing, enzymes involved in anthocyanin metabolism and transport, and anthocyanin metabolizing gut microbiota. However, it should be noted that the literature on anthocyanins bioavailability considering inter or intra-individual variability is still very scarce, which makes it difficult to reach any firm conclusion on the main metabolizing enzymes or bacteria that would be responsible for the variability in anthocyanin bioavailability.

Red Raspberry Polyphenols Attenuate High-Fat Diet-Driven Activation of NLRP3 Inflammasome and its Paracrine Suppression of Adipogenesis via Histone Modifications

SCOPE

The authors aim to investigate the mechanisms by which red raspberry (RR) polyphenolic fractions regulate obesity and inflammation with an emphasis on the crosstalk between adipose tissue macrophages (ATM) and adipocyte progenitors.

METHODS AND RESULTS

C57BL/6 male mice are fed either a high-fat (HF) diet or an HF diet supplemented with a RR polyphenolic fraction from whole fruit, pulp, or seed. Supplementation with pulp significantly increases energy expenditure and reduces HF-diet-induced obesity and insulin resistance. The pulp, and to a lesser extent, whole polyphenols, decreases the recruitment of ATM, activation of the nod-like receptor protein 3 (NLRP3) inflammasome, and adipocyte hypertrophy, which is associated with epigenetic modulation of adipogenesis (e.g., H3K27Ac, H3K9Ac). Results from an IL-1β reporter assay in J774 macrophages recapitulate the inhibitory role of RR polyphenols on NLRP3 inflammasome activation. Using conditioned media from macrophages, it is demonstrated that RR polyphenols reverse the IL-1β-mediated epigenetic suppression of H3K27Ac in adipocyte progenitor cells.

CONCLUSIONS

RR polyphenols from pulp and whole fruit serve as an inhibitor for NLRP3 inflammasome activation and an epigenetic modifier to regulate adipogenesis, which confers resistance against diet-induced obesity and metabolic dysfunction.

Anthocyanins-Nature's Bold, Beautiful, and Health-Promoting Colors

Anthocyanins are among the most interesting and vigorously studied plant compounds, representing a large class of over 700 polyphenolic pigments within the flavonoid family that exist ubiquitously in the human diet. They are "nature's colors," responsible for providing the beautiful red-orange to blue-violet hues present in many leaves, flowers, vegetables, and fruits, especially berries. The beginning of the 21st century has witnessed a renaissance in research activities on anthocyanins in several areas, mainly related to their potential health-promoting properties and their increased use as alternatives to synthetic food colors. There is increasingly convincing scientific evidence that supports both a preventative and therapeutic role of anthocyanins towards certain chronic disease states. Many anthocyanin-based extracts and juice concentrates from crop and/or food processing waste have become commercially available as colorants and/or value-added food ingredients. There is a large and evolving peer-reviewed literature on how anthocyanin chemistry and concentration may affect their coloring properties in food. Equally as important is the food matrix, which can have large impacts on anthocyanin color expression, stability and degradation, particularly regarding the applications of anthocyanins as food colorants and their health-promoting properties. This Special Edition of Foods, titled "Anthocyanins in Foods," presents original research that extends our understanding of these exciting and complex compounds.

Berry-Enriched Diet in Salt-Sensitive Hypertensive Rats: Metabolic Fate of (Poly)Phenols and the Role of Gut Microbiota

Diets rich in (poly)phenols are associated with a reduced reduction in the incidence of cardiovascular disorders. While the absorption and metabolism of (poly)phenols has been described, it is not clear how their metabolic fate is affected under pathological conditions. This study evaluated the metabolic fate of berry (poly)phenols in an in vivo model of hypertension as well as the associated microbiota response. Dahl salt-sensitive rats were fed either a low-salt diet (0.26% NaCl) or a high-salt diet (8% NaCl), with or without a berry mixture (blueberries, blackberries, raspberries, Portuguese crowberry and strawberry tree fruit) for 9 weeks. The salt-enriched diet promoted an increase in the urinary excretion of berry (poly)phenol metabolites, while the abundance of these metabolites decreased in faeces, as revealed by UPLC-MS/MS. Moreover, salt and berries modulated gut microbiota composition as demonstrated by 16S rRNA analysis. Some changes in the microbiota composition were associated with the high-salt diet and revealed an expansion of the families Proteobacteria and Erysipelotrichaceae. However, this effect was mitigated by the dietary supplementation with berries. Alterations in the metabolic fate of (poly)phenols occur in parallel with the modulation of gut microbiota in hypertensive rats. Thus, beneficial effects of (poly)phenols could be related with these interlinked modifications, between metabolites and microbiota environments.

Effects of Black Raspberries and Their Constituents on Rat Prostate Carcinogenesis and Human Prostate Cancer Cell Growth In Vitro

Prostate cancer patients often use dietary supplements, such as black raspberries, which are a rich source of compounds with antioxidant and anticancer activity, particularly on gastrointestinal cancers. Feeding black raspberries inhibited mammary cancer induction in rats and growth of cancer cells in nude mice, indicating systemic bioavailability of bioactive compounds. We tested whether feeding black raspberries and its constituents would inhibit prostate cancer development. However, we did not find preventive effects in two rat prostate carcinogenesis models, even though the berry anthocyanin metabolite protocatechuic acid was detectable in their prostates. Black raspberry extract, the anthocyanin cyanidin-3-rutinoside and protocatechuic acid did not inhibit prostate cancer cell growth in vitro, but ellagic acid and its urolithin A metabolite did at high concentrations. Prostate cancer cell migration was not affected by these agents nor was growth in soft agar, except that ellagic acid reduced colony formation at physiological concentrations and protocatechuic acid at high concentrations. Low bioavailability of bioactive berry compounds and metabolites may limit exposure of tissues such as the prostate, since we found that cyanidin-3-rutinoside was not bioavailable to prostate cancer cells, but its aglycone cyanidin was and inhibited their growth. Thus, black raspberries are unlikely to prevent prostate cancer.

Molecular Mechanisms and Bioavailability of Polyphenols in Prostate Cancer

Prostate cancer is the one of the most frequently diagnosed cancers among men over the age of 50. Several lines of evidence support the observation that polyphenols have preventive and therapeutic effects in prostate cancer. Moreover, prostate cancer is ideal for chemoprevention due to its long latency. We propose here an equilibrated lifestyle with a diet rich in polyphenols as prophylactic attempts to slow down the progression of localized prostate cancer or prevent the occurrence of the disease. In this review, we will first summarize the molecular mechanisms of polyphenols in prostate cancer with a focus on the antioxidant and pro-oxidant effects, androgen receptors (AR), key molecules involved in AR signaling and their transactivation pathways, cell cycle, apoptosis, angiogenesis, metastasis, genetic aspects, and epigenetic mechanisms. The relevance of the molecular mechanisms is discussed in light of current bioavailability data regarding the activity of polyphenols in prostate cancer. We also highlight strategies for improving the bioavailability of polyphenols. We hope that this review will lead to further research regarding the bioavailability and the role of polyphenols in prostate cancer prevention and treatment.

Impact of Fermentable Fibres on the Colonic Microbiota Metabolism of Dietary Polyphenols Rutin and Quercetin

Dietary fibre and polyphenols are both metabolised to short-chain fatty acids (SCFAs) and phenolic acids (PA) by the colonic microbiota. These may alter microbiota growth/diversity, but their interaction is not understood. Interactions between rutin and raftiline, ispaghula or pectin were investigated in human faecal batch cultures (healthy participants; 19⁻33 years, 4 males, 6 females, BMI 18.4⁻27.4) after a low (poly)phenol diet three days prior to study. Phenolic acids were measured by gas chromatography-mass spectrometry and SCFAs by gas chromatography-flame ionisation after 2, 4, 6, and 24 h. Rutin fermentation produced Phenyl acetic acid (PAA), 4-Hydroxy benzoic acid (4-OHBA), 3-Hydroxy phenyl acetic acid (3-OHPAA), 4-Hydroxy phenyl acetic acid (4-OHPAA), 3,4-Dihydroxy phenyl acetic acid (3,4-diOHPAA), 3-Hydroxy phenyl propionic acid (3-OHPPA), and 4-Hydroxy phenyl propionic acid (4-OHPPA). 3,4-DiOHPAA and 3-OHPAA were predominant at 6 h (1.9 ± 1.8 µg/mL, 2.9 ± 2.5 µg/mL, and 0.05 ± 0.0 µg/mL, respectively) and 24 h (5.5 ± 3.3 µg/mL, 3.1 ± 4.2 µg/mL, and 1.2 ± 1.6 µg/mL). Production of all PA except 3-OHPPA and 4-OHPPA was reduced by at least one fibre. Inhibition of PA was highest for rutin (8-fold, p < 0.01), then pectin (5-fold, p < 0.01), and ispaghula (2-fold, p = 0.03). Neither rutin nor quercetin had a detectable impact on SCFA production. These interactions should be considered when assessing dietary polyphenols and potential health benefits.

Polyphenols and bioavailability: an update

Based on many cell culture, animal and human studies, it is well known that the most challenge issue for developing polyphenolics as chemoprevention or anti-diabtetic agents is the low oral bioavailability, which may be the major reason relating to its ambiguous therapeutic effects and large inter-individual variations in clinical trials. This review intends to highlight the unscientific evaluation on the basis of the published data regarding in vitro bioactivity of polyphenols, which may sometimes mislead the researchers and to conclude that: first, bio-accessibilities values obtained in the studies for polyphenols should be highly reconsidered in accordance with the abundant newly identified circulating and excreted metabolites, with a particular attention to colonic metabolic products which are obviously contributing much more than expected to their absorptions; second, it is phenolic metabolites, which are formed in the small intestine and hepatic cells,low molecular weight catabolic products of the colonic microflora to travel around the human body in the circulatory system or reach body tissues to elicit bioactive effects. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.