Polyphenolic Metabolites Research Articles

Hydrothermal Treatments Affecting the Concentration of Neochlorogenic Acid in Dough of Tartary Buckwheat

This study investigated the effects of initial temperature treatments of gluten-free doughs made from Tartary buckwheat flour, and time of methanol extraction from the cooked doughs of neochlorogenic acid, an important polyphenol metabolite. The doughs were hydrothermally treated from 25 °C to 95 °C, cooked at 95 °C for 20 min, and extracted using 80% aqueous methanol at the room temperature for 20 min, 2 h, and 8 h. For the control, nonhydrothermally treated Tartary buckwheat flour samples, the extractable neochlorogenic acid was similar for these extraction times. For the cooked dough samples, the hydrothermal treatments were important in terms of extractability of neochlorogenic acid. The extractable neochlorogenic acid was higher for the control samples in comparison to the hydrothermally treated and cooked dough samples. Among these hydrothermally treated dough samples, the high extractable neochlorogenic acid concentrations were maintained for temperatures of at least 80 °C. These high-temperature initial treatments during dough preparation appear to prevent degradation of the neochlorogenic acid in Tartary buckwheat flour. During hydrothermal treatment, neochlorogenic acid is bound to grain structures in such a way that prolonged extraction time is needed to extract it.

Pharmacokinetic Characterization of (Poly)phenolic Metabolites in Human Plasma and Urine after Acute and Short-Term Daily Consumption of Mango Pulp.

Pharmacokinetic (PK) evaluation of polyphenolic metabolites over 24 h was conducted in human subjects (n = 13, BMI = 22.7 ± 0.4 kg/m2) after acute mango pulp (MP), vitamin C (VC) or MP + VC test beverage intake and after 14 days of MP beverage intake. Plasma and urine samples were collected at different time intervals and analyzed using targeted and non-targeted mass spectrometry. The maximum concentrations (Cmax) of gallotannin metabolites were significantly increased (p < 0.05) after acute MP beverage intake compared to VC beverage alone. MP + VC beverage non-significantly enhanced the Cmax of gallic acid metabolites compared to MP beverage alone. Pyrogallol (microbial-derived metabolite) derivatives increased (3.6%) after the 14 days of MP beverage intake compared to 24 h acute MP beverage intake (p < 0.05). These results indicate extensive absorption and breakdown of gallotannins to galloyl and other (poly)phenolic metabolites after MP consumption, suggesting modulation and/or acclimation of gut microbiota to daily MP intake.

Early Infant Formula Feeding Impacts Urinary Metabolite Profile at 3 Months of Age.

There is a growing consensus that nutritional programming may persist and influence risk for several chronic diseases in adulthood. In the present study, we used urinary metabolic analysis in assessing diet effects on early-life metabolism. Urine samples from healthy three-month-old infants fed human milk (HM; n = 93), cow’s milk-based infant formula [MF; n = 80], or soy protein-based infant formula (SF; n = 76) were analyzed with an untargeted metabolomics approach using GC-TOF MS. PLS-DA and ANOVA analyses were performed using MetaboAnalyst (v4.0). A total of 150 metabolites differed significantly among the feeding groups, including dietary-specific patterns of urinary metabolites of sugars, sugar alcohols, amino acids, and polyphenols. Urinary metabolites may mirror the infant’s overall metabolism and serve as a noninvasive tool to examine the neonatal effects of diet on early-infant metabolism.

Hemin Prevents Increased Glycolysis in Macrophages upon Activation: Protection by Microbiota-Derived Metabolites of Polyphenols.

Meat consumption plays a critical role in the development of several types of cancer. Hemin, a metabolite of myoglobin produced after meat intake, has been demonstrated to be involved in the cancer initiation phase. Macrophages are key components of the innate immunity, which, upon activation, can prevent cancer development by eliminating neoplastic cells. Metabolic reprogramming, characterized by high glycolysis and low oxidative phosphorylation, is critical for macrophage activation. 3,4-dihydroxyphenylacetic acid (3,4DHPAA) and 4-hydroxyphenylacetic acid (4HPAA), both microbiota-derived metabolites of flavonoids, have not been extensively studied although they exert antioxidant properties. The aim of this study was to determine the effect of hemin on the anticancer properties of macrophages and the role of 3,4DHPAA and 4HPAA in metabolic reprogramming and activation of macrophages leading to the elimination of cancer cells. The results showed that hemin inhibited glycolysis, glycolytic, and pentose phosphate pathway (PPP) enzyme activities and hypoxia-inducible factor-1 alpha (HIF-1α) stabilization, which interferes with macrophage activation (evidenced by decreased interferon-γ-inducible protein 10 (IP-10) release) and their ability to eliminate cancer cells (via cytotoxic mediators and phagocytosis). Hemin also reduced the mitochondrial membrane potential (MMP) and mitochondrial mass in macrophages. 3,4DHPAA and 4HPAA, by stimulating glycolysis and PPP, prevented the impairment of the macrophage anticancer activity induced by hemin. In conclusion, 3,4HPAA and 4HPAA administration could represent a promising strategy for preventing the reduction of macrophage activation induced by hemin.

The Relationship between Dietary Polyphenol Intakes and Urinary Polyphenol Concentrations in Adults Prescribed a High Vegetable and Fruit Diet.

Urinary polyphenol metabolites are potential biomarkers of dietary polyphenol intake. The current study aims to evaluate associations between total diet, vegetable and fruit polyphenol intakes with urinary polyphenol metabolite concentrations in a sample of adults prescribed a diet rich in vegetables and fruit. Thirty-four participants completed a 10-week pre-post study. Participants were asked to consume Australian recommended daily vegetable and fruit serves and attend measurement sessions at baseline and at weeks 2 and 10. Two 24-h diet recalls were collected at each time-point and polyphenol intakes were calculated using the Phenol-Explorer database. Spot urine samples, collected at each time-point, were analyzed for 15 polyphenol metabolites using liquid chromatography-mass spectroscopy. Spearman’s correlation analyzes assessed the strength of relationships between urinary and dietary polyphenols. Linear mixed models were used to investigate relationships between polyphenol excretion and intake. Total urinary polyphenols were significantly correlated with total polyphenol intakes at week 10 (rs = 0.47) and fruit polyphenols at week 2 (rs = 0.38). Hippuric acid was significantly correlated with vegetable polyphenols at baseline (rs = 0.39). Relationships were identified between individual polyphenol metabolites and vegetable and fruit polyphenols. Linear mixed model analyzes identified that for every 1 mg increase in polyphenol intakes, urinary polyphenol excretion increased by 16.3 nmol/g creatinine. Although the majority of relationships were not sufficiently strong or consistent at different time-points, promising relationships were observed between total urinary polyphenols and total polyphenol intakes, and hippuric acid and vegetable polyphenols.

Naturally Occurring Flavonoids and Isoflavonoids and Their Microbial Transformation: A Review.

Flavonoids and isoflavonoids are polyphenolic secondary metabolites usually produced by plants adapting to changing ecological environments over a long period of time. Therefore, their biosynthesis pathways are considered as the most distinctive natural product pathway in plants. Seemingly, the flavonoids and isoflavones from fungi and actinomycetes have been relatively overlooked. In this review, we summarized and classified the isoflavones and flavonoids derived from fungi and actinomycetes and described their biological activities. Increasing attention has been paid to bioactive substances derived from microorganism whole-cell biotransformation. Additionally, we described the utilization of isoflavones and flavonoids as substrates by fungi and actinomycetes for biotransformation through hydroxylation, methylation, halogenation, glycosylation, dehydrogenation, cyclisation, and hydrogenation reactions to obtain rare and highly active biofunctional derivatives. Overall, among all microorganisms, actinomycetes are the main producers of flavonoids. In our review, we also summarized the functional genes involved in flavonoid biosynthesis.

Dietary Supplementation with Olive Mill Wastewater in Dairy Sheep: Evaluation of Cheese Characteristics and Presence of Bioactive Molecules

Simple SummaryUsing polyphenols from olive oil waste as feed supplements in animal diets can be a strategy to reduce adverse environmental effects of this by-product and to enhance the quality of products of animal origin. The aim of the study was to assess the effects of adding a polyphenolic concentrate from olive oil wastewater to a typical sheep diet on the nutraceutical and quality characteristics of cheese. The experiment was carried out on thirty-six Sarda ewes, divided into two homogenous groups fed a standard diet composed of hay and concentrate. In one of the two diets, the concentrate was supplemented (25 g/kg) with polyphenols obtained from olive mill wastewater using a special filtration system. Data showed that the polyphenol supplementation in the ewe’s diet resulted in the presence of tyrosol and hydroxytyrosol sulphate metabolites in milk and cheese. Furthermore, these compounds were able to provide a direct antioxidant effect on cheese with no modification in its chemical composition.The aim of the study was to define the chemical characteristics, antioxidant capacity, oxidative status, sensory properties, and the presence of polyphenols in ovine cheese obtained after dietary administration of spray-dried olive mill wastewater (SDP). SDP is a waste from olive oil production rich in bioactive molecules obtained by further processing the olive mill wastewater through a spray-drying system. Thirty-six sheep were randomly assigned to two experimental groups that received a standard diet based on hay and concentrate. The concentrate fed to the SDP group was supplemented with SDP at a rate 25 g/kg (as fed). The trial lasted 9 weeks. Milk from the two treatment groups was separately collected and used for manufacturing cheese. Cheese quality parameters and proximate composition were not affected by the dietary treatment, whereas the antioxidant status and oxidative stability of cheese were positively affected. Polyphenol analyses in cheese were performed through liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The concentration of hydroxytyrosol and tyrosol, and their sulphate metabolites, were higher in cheese from supplemented sheep. These findings suggest that polyphenol metabolites can play a major role in the beneficial effects observed in food produced from sheep fed SDP.

Investigating the heat stability, calorimetric degradations and chromatographic polyphenolic profiling of edible macerated hog-tree apple leaf (Morinda lucida Benth)

The increasing demand for food-based bio-products has necessitated screening characterizations and microstructural elucidation. In this study, different analytical techniques were employed to investigate the thermal stability, morphological changes and phenolic profile of macerated hog-tree apple leaf. TGA peak heights from the thermo-gravimetric decomposition curve could be attributed to mass evaporation and simultaneous removal of residual moisture from the sample accounting for 0.9239 mg mass loss from 5.825 mg of the total sample. The TGA results suggest that the 87 polyphenolic metabolites recovered from the sample occurred between 71.94 °C and 243.55 °C with 3.871 mg mass loss from 5.825 mg from the total sample loading. In this region eighty-seven compounds were identified which include mainly the phenolic and flavonoids viz: isochlorogenic acid, trans-ferulaldehyde, 10-O-methylprotosappanin, moracin G, terchebin, geraniin, albaspidin AA. These has been reported in previous studies as strong antioxidant compounds. Moreover, the SEM monograph generated further elucidated the morphological changes and surface degradation of Morinda lucida Benth which resulted in the exudation of phenolic constituents. The result of this investigation could, therefore, be used as blueprints for storage and post-harvest processing of edible M. lucida Benth.

Saccharomyces Cerevisiae-An Interesting Producer of Bioactive Plant Polyphenolic Metabolites.

Secondary phenolic metabolites are defined as valuable natural products synthesized by different organisms that are not essential for growth and development. These compounds play an essential role in plant defense mechanisms and an important role in the pharmaceutical, cosmetics, food, and agricultural industries. Despite the vast chemical diversity of natural compounds, their content in plants is very low, and, as a consequence, this eliminates the possibility of the production of these interesting secondary metabolites from plants. Therefore, microorganisms are widely used as cell factories by industrial biotechnology, in the production of different non-native compounds. Among microorganisms commonly used in biotechnological applications, yeast are a prominent host for the diverse secondary metabolite biosynthetic pathways. Saccharomyces cerevisiae is often regarded as a better host organism for the heterologous production of phenolic compounds, particularly if the expression of different plant genes is necessary.

Polyphenols bind to low density lipoprotein at biologically relevant concentrations that are protective for heart disease

There is ample evidence in the epidemiological literature that polyphenols, the major non-vitamin antioxidants in plant foods and beverages, have a beneficial effect on heart disease. Until recently other mechanisms which polyphenols exhibit such as cell signaling and regulating nitric oxide bioavailability have been investigated. The oxidation theory of atherosclerosis implicates LDL oxidation as the beginning step in this process. Nine polyphenols from eight different classes and several of their O-methylether, O-glucuronide and O-sulfate metabolites have been shown in this study to bind to the lipoproteins and protect them from oxidation at lysosomal/inflammatory pH (5.2), and physiological pH (7.4). Polyphenols bind to the apoprotein at pH 7.4 with Kb > 106 M−1 and the number of molecules of polyphenols bound per LDL particle under saturation conditions varied from 0.4 for ferulic acid to 13.1 for quercetin. Competition studies between serum albumin and LDL show that substantial lipoprotein binding occurs even in the presence of a great molar excess of albumin, the major blood protein. These in vitro results are borne out by published human supplementation studies showing that polyphenol metabolites from red wine, olive oil and coffee are found in LDL even after an overnight fast. A single human supplementation with various fruit juices, coffee and tea also produced an ex vivo protection against lipoprotein oxidation under postprandial conditions. This in vivo binding is heart-protective based on published olive oil consumption studies. Relevant to heart disease, we hypothesize that the binding of polyphenols and metabolites to LDL functions as a transport mechanism to carry these antioxidants to the arterial intima, and into endothelial cells and macrophages. Extracellular and intracellular polyphenols and their metabolites are heart-protective by many mechanisms and can also function as potent “intraparticle” and intracellular antioxidants due to their localized concentrations that can reach as high as the micromolar level. Low plasma concentrations make polyphenols and their metabolites poor plasma antioxidants but their concentration in particles such as lipoproteins and cells is high enough for polyphenols to provide cardiovascular protection by direct antioxidant effects and by other mechanisms such as cell signaling.

Algae Polyphenolic Compounds and Modern Antibacterial Strategies: Current Achievements and Immediate Prospects.

The increasing drug resistance of pathogenic microorganisms raises concern worldwide and necessitates the search for new natural compounds with antibacterial properties. Marine algae are considered a natural and attractive biotechnological source of novel antibiotics. The high antimicrobial activity of their polyphenolic compounds is a promising basis for designing innovative pharmaceuticals. They can become both a serious alternative to traditional antimicrobial agents and an effective supplement to antibiotic therapy. The present review summarizes the results of numerous studies on polyphenols from algae and the range of biological activities that determine their biomedical significance. The main focus is put on a group of the polyphenolic metabolites referred to as phlorotannins and, particularly, on their structural diversity and mechanisms of antimicrobial effects. Brown algae are an almost inexhaustible resource with a high biotechnological potential for obtaining these polyfunctional compounds. An opinion is expressed that the effectiveness of the antibacterial activity of phlorotannins depends on the methods of their extraction aimed at preserving the phenolic structure. The use of modern analytical tools opens up a broad range of opportunities for studying the metabolic pathways of phlorotannins and identifying their structural and functional relationships. The high antimicrobial activity of phlorotannins against both Gram-positive and Gram-negative bacteria provides a promising framework for creating novel drugs to be used in the treatment and prevention of infectious diseases.

Effects of feeding graded levels of whole cottonseed on haemato-biochemical parameters of red Sokoto bucks

Whole cottonseed (WCS) is an important source of protein for ruminants, however, it contains a polyphenolic secondary metabolite gossypol which may reduce its palatability and cause pathophysiological effects. The study was aimed at evaluating the effects of feeding graded levels of WCS on the haemato-biochemical parameters of Red Sokoto bucks (RSB). After a 14-day pre-treatment period, 20 bucks (n = 5) were assigned for 90 days to one of four isonitrogeneous treatments: control (A); 0 % (B); 15 % (C); 30 % and (D); 45 %. Blood was collected for Packed Cell Volume (PCV) and serum analyses at days 0, 45 and 90 of the experimental period for concentrations of urea, creatinine, total protein, albumin, globulin and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP). The PCV was decreased in groups fed above 15 % of WCS on days 45. There were no significant (P &gt; 0.05) differences in globulin concentration, alanine aminotransferase and alkaline phosphatase activities but aspartate transferase activity was higher (p &lt; 0.05) in group D (45% WCS) compared to the various treatment groups. The urea concentration was higher (p &lt; 0.05) in groups B and D at day 45 compared to the control group. The creatinine concentration was higher (p &lt; 0.05) in group D at days 45 and 90 compared to the control group. The serum total protein and albumin concentration were higher (p &lt; 0.05) in groups C and D at day 45 compared to the control group. Our finding revealed that prolonged feeding of bucks above 30 % WCS for more than 60 days exerted considerable deleterious and adverse effects on blood constituents leading to aneamia, hyper-cretenaemia, ureamia, increased levels of total protein, albumin, aspartate transferase activity and death.&#x0D; Keywords: Biochemical parameters, Bucks, Gossypol, Serum, Whole cotton seed

Basic and clinical science posters: Beta cells, islets and stem cells

Aims: The intestinal microbiota plays an important role in host metabolism via production of dietary metabolites. Microbiota imbalances are linked to type 2 diabetes, but dietary modification of the microbiota may promote glycaemic control. This study investigated whether differences in gut microbiota between control and diabetic mice influence the production of polyphenolic metabolites from wheat wholegrain (WW). Second, the study assessed whether changes in metabolite profiles affect pancreatic beta cell function. Methods: Faecal samples (1% (v/v)) from control or high‐fat high‐fructose fed (HFHF) mice were fermented in vitro with 0.1% (w/v) WW for 0, 6 and 24 h. Polyphenolic profiles were determined by UHPLC‐MS/MS and microbiota composition by bacterial 16S rRNA sequencing and qPCR. MIN6 beta cell apoptosis was assessed by measurement of caspase activity and insulin release by radioimmunoassay. Results: Levels of WW polyphenols were decreased in fermentation samples from HFHF with time and HFHF showed an overall dysbiotic microbiome profile (p 0.05, n=3). Insulin secretion was inhibited at 0 h by control, but not HFHF supernatant, and this effect was partly reverted at 24 h (p < 0.05, n=5). Conclusion: Our results suggest that a dysbiotic HFHF microbiota profile affects the production of polyphenolic metabolites with potential implications for beta cell function.

Urolithins Attenuate Multiple Symptoms of Obesity in Rats Fed on a High-Fat Diet.

BackgroundUrolithins are gut microbiota-derived polyphenol metabolites, produced following the consumption of pomegranate, berries, and nuts. Recent studies have shown the potentials of these metabolites on reducing triglycerides accumulation in cultured hepatocytes and adipocytes. In this study, we investigated the ability of both urolithin A (Uro-A) and urolithin B (Uro-B) to attenuate obesity and associated symptoms in a high-fat diet-induced obesity model in rats.MethodsTwenty-four male Wistar rats were randomly assigned to four groups. Group 1 was fed on a normal diet while groups 2, 3, and 4 were fed on a high-fat diet for 10 weeks. After this, groups 3 and 4 were treated with 2.5mg/kg body weight of Uro-A and Uro-B intraperitoneally, respectively. Body weight, serum lipid profile, hepatic antioxidant activity, hepatic lipid accumulation, fecal lipid content, and the expressions of genes involved in lipogenesis and hepatic ER stress were quantified.ResultsIndeed, a high-fat diet resulted in increased body weight, visceral adipose tissue mass, and oxidative stress in rats. However, treatment with both Uro-A and Uro-B decreased body weight and visceral adipose tissue mass. These metabolites restored hepatic antioxidant capacity and decreased lipid accumulation in addition to an increase in fecal fat excretion. Moreover, both Uro-A and Uro-B treatment downregulated the expression of LXRα and SREBP1c; involved in de novo lipogenesis while upregulating PPARα expression for increased fatty acid oxidation. Furthermore, Uro-A and Uro-B decreased the expression of PERK and IRE1α; which are involved in hepatic ER stress. Taken together, our results showed the potentials of Uro-A and Uro-B in mitigating obesity symptoms and they could thus provide promising roles in the future as functional anti-obesity candidates.

Metabolomic Signatures of Long-term Coffee Consumption and Risk of Type 2 Diabetes in Women.

Coffee may protect against multiple chronic diseases, particularly type 2 diabetes, but the mechanisms remain unclear. Leveraging dietary and metabolomic data in two large cohorts of women (the Nurses' Health Study [NHS] and NHSII), we identified and validated plasma metabolites associated with coffee intake in 1,595 women. We then evaluated the prospective association of coffee-related metabolites with diabetes risk and the added predictivity of these metabolites for diabetes in two nested case-control studies (n = 457 case and 1,371 control subjects). Of 461 metabolites, 34 were identified and validated to be associated with total coffee intake, including 13 positive associations (primarily trigonelline, polyphenol metabolites, and caffeine metabolites) and 21 inverse associations (primarily triacylglycerols [TAGs] and diacylglycerols [DAGs]). These associations were generally consistent for caffeinated and decaffeinated coffee, except for caffeine and its metabolites that were only associated with caffeinated coffee intake. The three cholesteryl esters positively associated with coffee intake showed inverse associations with diabetes risk, whereas the 12 metabolites negatively associated with coffee (5 DAGs and 7 TAGs) showed positive associations with diabetes. Adding the 15 diabetes-associated metabolites to a classical risk factor-based prediction model increased the C-statistic from 0.79 (95% CI 0.76, 0.83) to 0.83 (95% CI 0.80, 0.86) (P < 0.001). Similar improvement was observed in the validation set. Coffee consumption is associated with widespread metabolic changes, among which lipid metabolites may be critical for the antidiabetes benefit of coffee. Coffee-related metabolites might help improve prediction of diabetes, but further validation studies are needed.

Hydroxypropyl-β-Cyclodextrin as a Green Co-Solvent in the Aqueous Extraction of Polyphenols from Waste Orange Peels

There is, to-date, an expanding interest concerning the use of cyclodextrins as green food-grade co-solvents in the aqueous extraction of polyphenols, however, data regarding polyphenol extraction from waste orange peels (WOP) are lacking. On this ground, hydroxypropyl β-cyclodextrin (HP-β-CD), a highly water-soluble cyclodextrin, was used to develop a simple and straightforward methodology for the effective recovery of WOP polyphenols. Process optimization by response surface showed that maximum total polyphenol recovery (26.30 ± 1.49 mg gallic acid equivalents g−1 dry mass) could be accomplished with 15 mM HP-β-CD at 40 °C. On the other hand, integration of ultrasonication pretreatment was found unsuitable, as it resulted in reduced polyphenol yield. Examination of solvent acidity indicated that polyphenol extraction may be enhanced at pH 4, but the difference was non-significant (p &gt; 0.05) compared to yields attained at pH 2, 3, and 5. Extraction of WOP polyphenols with HP-β-CD was shown to provide significantly higher hesperidin yield compared to 60% (v/v) aqueous ethanol, which suggested selectivity of HP-β-CD toward this polyphenolic metabolite.

Apple polyphenol-rich drinks dose-dependently decrease early-phase postprandial glucose concentrations following a high-carbohydrate meal: a randomized controlled trial in healthy adults and in vitro studies

BackgroundPrevious research demonstrated that a high dose of phlorizin-rich apple extract (AE) can markedly inhibit early-phase postprandial glycemia, but efficacy of lower doses of the AE is unclear. ObjectiveTo determine whether lower AE doses reduce early-phase postprandial glycemia in healthy adults and investigate mechanisms. DesignIn a randomized, controlled, double-blinded, cross-over acute trial, drinks containing 1.8 g (HIGH), 1.35 g (MED), 0.9 g (LOW), or 0 g (CON) of a phlorizin-rich AE were consumed before 75 g starch/sucrose meal. Postprandial blood glucose, insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP) and polyphenol metabolites concentrations were measured 0–240 min, acetaminophen concentrations to assess gastric emptying rate, and 24 h urinary glucose excretion. Effects of AE on intestinal glucose transport were investigated in Caco-2/TC7 cells. ResultsAE significantly reduced plasma glucose iAUC 0–30 min at all doses: mean differences (95% CI) relative to CON were −15.6 (−23.3, −7.9), −11.3 (−19.6, −3.0) and −8.99 (−17.3, −0.7) mmol/L per minute for HIGH, MEDIUM and LOW respectively, delayed Tmax (HIGH, MEDIUM and LOW 45 min vs. CON 30 min), but did not lower Cmax. Similar dose-dependent treatment effects were observed for insulin, C-peptide, and GIP. Gastric emptying rates and urinary glucose excretion did not differ. Serum phloretin, quercetin and epicatechin metabolites were detected postprandially. A HIGH physiological AE dose equivalent decreased total glucose uptake by 48% in Caco-2/TC7 cells. ConclusionsPhlorizin-rich AE, even at a low dose, can slightly delay early-phase glycemia without affecting peak and total glycemic response.

Analysis of polyphenolic metabolites from in vitro gastrointestinal digested soft fruit extracts identify malvidin-3-glucoside as an inhibitor of PTP1B

Protein-tyrosine phosphatase 1B (PTP1B, EC 3.1.3.48) is an important regulator of insulin signalling. Herein, we employed experimental and computational biology techniques to investigate the inhibitory properties of phenolics, identified from four in vitro gastrointestinal digested (IVGD) soft fruits, on PTP1B. Analysis by LC-MS/MS identified specific phenolics that inhibited PTP1B in vitro. Enzyme kinetics identified the mode of inhibition, while dynamics, stability and binding mechanisms of PTP1B-ligand complex were investigated through molecular modelling, docking, molecular dynamics (MD) simulations, and MM/PBSA binding free energy estimation. IVGD extracts and specific phenolics identified from the four soft fruits inhibited PTP1B (P < 0.0001) activity. Among the phenolics tested, the greatest inhibition was shown by malvidin-3-glucoside (P < 0.0001) and gallic acid (P < 0.0001). Malvidin-3-glucoside (Ki = 3.8 µg/mL) was a competitive inhibitor and gallic acid (Ki = 33.3 µg/mL) a non-competitive inhibitor of PTP1B. Malvidin-3-glucoside exhibited better binding energy than gallic acid and the synthetic inhibitor Dephostatin (−7.38 > −6.37 > −5.62 kcal/mol) respectively. Principal component analysis demonstrated malvidin-3-glucoside PTP1B-complex occupies more conformational space where critical WPD-loop displayed a higher degree of motion. MM/PBSA binding free energy for malvidin-3-glucoside to PTP1B was found to be higher than other complexes mediated by Van der Waals energy rather than electrostatic interaction for the other two inhibitors (-80.32 ± 1.25 > −40.64 ± 1.43 > −21.63 ± 1.73 kcal/mol) respectively. Altogether, we have established novel insights into the specific binding of dietary phenolics and have identified malvidin-3-glucoside as an PTP1B inhibitor, which may be further industrially developed for the treatment of type-2 diabetes.

P0937IMPACT OF TANNINS AS FOOD SUPPLEMENT IN A CKD POPULATION WITH RECURRENT URINARY TRACT INFECTIONS: PRELIMINARY DATA

Abstract Background and Aims Urinary tract infections (UTIs) are estimated to account for over 7 million office visits per year. UTIs are about 50 times more frequent in women than in men, however, in men the incidence steeply increases after 50 years of age for prostate involvement. UTI diagnosis is based on symptoms and urinalysis. Antibiotic therapy is often required in subjects with relapsing UTIs. Therefore, it would be useful to develop a therapeutic strategy based on natural active compounds, free from side effects (such as on renal function), that could counteract UTIs recurrence. For this purpose, tannins (TNs) could represent a valid therapeutic alternative. TNs are polyphenolic compounds known for their anti-inflammatory, antimicrobial and antioxidant effects. Recent studies highlighted how TNs intake can counteract UTI recurrence, improving the quality of life. The aim of our study was to evaluate the beneficial action of chestnut TNs administered as oral food supplement (OFS) in recurrent UTI patients. Method OFS was characterized by HPLC/DAD/MS analysis for its content in secondary polyphenolic metabolites and by Folin-Ciocalteau in vitro tests for its antioxidative and anti-free radical activity with stable radical DPPH•. For in vivo tests, 16 chronic kidney disease (CKD) patients (8 female and 8 males) who suffered from recurrent UTIs, were recruited. The OFS was administered in 2 cps/ day, for 9 weeks. Patients were evaluated at T0= baseline and T1= after 9 weeks of OFS treatment. We performed laboratory and urinary tests, and the quality of life (SCL-90R questionnaire) and body composition (bioimpedentiometry) assessment. All parameters and questionnaires were evaluated at T0 and T1. At the same time, oxidative stress (OS) and antioxidant defenses were monitored using CR4000 (FORD and FORT tests). Results HPLC/DAD/MS quali-quantitative analysis allowed for an in depth chemical characterization of the individual polyphenols present in the OFS: total tannins amount is 10.542mg/g, whereas total anthocyanins are 1.885mg/g. The Folin Ciocalteu assay results show a total polyphenols content of 68.7mg/g GAE; the antiradical activity by DPPH assay is 94% for a solution 0.519mg/mL of powder. The epidemiological features of the population were reported in Table 1 and it was divided into two subgroups, according to gender. Laboratory parameters were reported in Table 2. During the study, we observed a drop out of three female subjects because of gastrointestinal (GI) disorders (nausea, gastric heartburn). We did not find any significative change in body composition parameters after OFS treatment. We highlighted a significant reduction (Table 3) of ESR only in male patients (16,7± 2,2 mm/h vs 11,3± 1,5 mm/h, p=0,0062). The urinalysis, showed a significant reduction of leukocytes in both subgroups (male: 43,5 (1-450) n/uL vs 15 ± 5,7 n/uL p = 0,0391; female: 28,5 (1-990) n/uL vs 7 (1-91) n/uL p= 0,0625) but urinary bacterial flora, after OFS supplementation significantly decreased only in male subjects (428 ± 143,4 n/uL vs 34 (0- 450) n/uL p= 0,0156). Interestingly we observed a significant reduction of OS parameters after OFS treatment as reported in Table 4. We also observed a reduction of the anxious and depressive components in male subjects in the SCL-90R questionnaire. Conclusion TNs seem to exert an antimicrobial action in a gender dependent manner, useful to counteract the recurrence of UTIs. OFS contains Serenoa repens, a substance with peripheral, antispastic and antiandrogenic action that could induce nausea and vomiting. Female patients dropped out for GI disorders had lower body weight and SR probably were overdosed for their body mass. In male subjects, the decrease in anxiety and depression at the end of the study, could be linked to the improvement of the urinary symptomatology. A randomized clinical trial conducted a larger population is needed to confirm these findings and explain the correlation with gender.

Microbiome, Pre-Diabetes and Polyphenol Metabolites: Insights and Interactions in Humans After 4-Week Dietary Intervention with Red Raspberries and Prebiotics

Abstract Objectives 1) To assess the polyphenol metabolites including microbial-derived metabolites after acute and 4-week red raspberry (RRB) supplementation with and without fructo-oligosaccharide (FOS) prebiotic; 2) to evaluate the gut microbiome for possible metagenomic biomarkers of lean and obese individuals with prediabetes and insulin resistance (PreDM) in response to RRB and FOS supplementation. Methods In a randomized, 4-week crossover clinical trial, subjects (n = 36: PreDM, n = 26; metabolically-healthy reference group, n = 10) consumed RRB (1 cup fresh equivalence) or RRB with 8 g FOS per day for 4 weeks separated by 4-week washout. Body composition, metabolic panel, polyphenol metabolites and gut microbiome were evaluated every 4 weeks for 12 weeks using standard clinical assessment protocols, ultra-high-pressure liquid chromatography-triple quadrupole and fecal metagenomic analysis with whole-metagenome shotgun sequencing, respectively. Statistical analysis was performed using, LEfSe, STAMP and SAS. Results Pre-supplementation, PreDM group was characterized by overabundant Blautia obeum and Blautia wexlerae, which positively correlated with measures of insulin resistance (P &amp;lt; 0.05). The obese PreDM subgroup (n = 15) compared to lean PreDM (n = 11) were characterized by lower abundance of Bifidobacterium spp., such as Bifidobacterium longum, which negatively correlated with waist and trunk fat% (P &amp;lt; 0.05). RRB supplementation significantly increased Clostridium orbiscindens (P = 0.044), a bacterium with polyphenol metabolizing capability, which negatively correlated with cholesterol ratio. Adding FOS to RRB significantly increased Bifidobacterium spp. in all participants (P &amp;lt; 0.05) and reduced B. obeum and B. wexlerae in PreDM. Over 170 RRB polyphenol metabolites, e.g., parent anthocyanins, urolithins, phenolic acids, γ-valerolactones and their glucuronide, sulfate, methyl conjugates were detected in plasma and urine and preliminary data suggests select metabolites increased over the supplementation period. Conclusions Compositional characteristics of gut microbiome shifted by incorporating combination of RRB and FOS daily in the diet. The data provide possible insight on the role of gut microbiome on clinical markers and polyphenol metabolite pools. Funding Sources Funds were provided by the National Processed Raspberry Council.