Acylated anthocyanins: A review on their bioavailability and effects on postprandial carbohydrate metabolism and inflammation

Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.</p

NMR-based metabolomics approach on optimization of malolactic fermentation of sea buckthorn juice with Lactiplantibacillus plantarum

This work investigated the impact of malolactic fermentation on the metabolomic profile of sea buckthorn juice to optimize the fermentation process for flavor modification. Six strains of L. plantarum were used with varied pH of the juice, cell acclimation, and fermentation time. 1H-NOESY spectra were acquired from fresh and fermented juices with a total of 46 metabolites identified. Less sugars and quinic acid were metabolized at pH 2.7 while oxidation of ascorbic acid was reduced at pH 3.5. l-Malic acid, essential amino acids, and nucleosides were consumed early during fermentation while sugars in general were consumed later in the fermentation. If deacidification is the main target of fermentation, strains that produce less acids and ferment less sugars, shorter fermentation time, and lower starter pH should be used. Higher starter pH and longer fermentation time promote formation of antimicrobial compounds and potentially increase antioxidant stability. </p

NMR metabolome of Borrelia burgdorferi in vitro and in vivo in mice

Lyme borreliosis (LB), caused by bacteria of the Borrelia burgdorferi sensu lato (Borrelia) species, isthe most common tick-borne infection in the northern hemisphere. LB diagnostics is based on clinicalevaluation of the patient and on laboratory testing, where the main method is the detection of Borreliaspecific antibodies in patient samples. There are, however, shortcomings in the current serology basedLB diagnostics, especially its inability to differentiate ongoing infection from a previously treated one.Identification of specific biomarkers of diseases is a growing application of metabolomics. One of themain methods of metabolomics is nuclear magnetic resonance (NMR) spectroscopy. In the presentstudy, our aim was to analyze whether Borrelia growth in vitro and infection in vivo in mice causesspecific metabolite differences, and whether NMR can be used to detect them. For this purpose,we performed NMR analyses of in vitro culture medium samples, and of serum and urine samples ofBorrelia infected and control mice. The results show, that there were significant differences in theconcentrations of several amino acids, energy metabolites and aromatic compounds between Borreliaculture and control media, and between infected and control mouse serum and urine samples. Forexample, the concentration of L-phenylalanine increases in the Borrelia growth medium and in serum ofinfected mice, whereas the concentrations of allantoin and trigonelline decrease in the urine of infectedmice. Therefore, we conclude that Borrelia infection causes measurable metabolome differences in vitroand in Borrelia infected mouse serum and urine samples, and that these can be detected with NMR.</p

Metabolomic discrimination of the edible mushrooms Kuehneromyces mutabilis and Hypholoma capnoides (Strophariaceae, Agaricales) by NMR spectroscopy

Two edible, cultivable mushroom species of the family Strophariaceae, Kuehneromyces mutabilis (sheathed woodtuft) and Hypholoma capnoides (conifer tuft), were studied using proton nuclear magnetic resonance metabolomic approach. The variation in the metabolites of the two species and their metabolic behaviourregarding caps and stipes and different collection sites were analysed by multivariate analysis methods. Altogether 169 cap and stipe samples of the mushrooms were investigated. The clearest difference between the species was in the sugar composition, which was more diverse in H. capnoides. When mushroom samples collected from different locations were compared, more variance was found in H. capnoides, whereas K. mutabilis appeared more homogeneous as a species. As far as the caps and stipes were concerned, in both species the amount of α-α-trehalose was clearly higher in the stipes, and the caps contained a larger proportion of the amino acids and organic acids.</p

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 mu M 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.</div

Anthocyanin-rich extract from purple potatoes decreases postprandial glycemic response and affects inflammation markers in healthy men

Our recent clinical study suggested that polyphenol-rich purple potatoes lowered postprandial glycemia and insulinemia compared to yellow potatoes. Here, 17 healthy male volunteers consumed yellow potatoes with or without purple potato extract (PPE, extracted with water/ethanol/acetic acid) rich in acylated anthocyanins (152 mg) and other phenolics (140 mg) in a randomized cross-over trial. Ethanol-free PPE decreased the incremental area under the curve for glucose (p = 0.019) and insulin (p = 0.015) until 120 min after the meal, glucose at 20 min (p = 0.015) and 40 min (p = 0.004), and insulin at 20 min (p = 0.003), 40 min (p = 0.004) and 60 min (p = 0.005) after the meal. PPE affected some of the studied 90 inflammation markers after meal; for example insulin-like hormone FGF-19 levels were elevated at 240 min (p = 0.001). These results indicate that PPE alleviates postprandial glycemia and insulinemia, and affects postprandial inflammation.</p

Effects of Anthocyanin Extracts from Bilberry (Vaccinium myrtillus L.) and Purple Potato (Solanum tuberosum L. var. ‘Synkeä Sakari’)on the Plasma Metabolomic Profile of Zucker Diabetic Fatty Rats

This study compared the effects of the nonacylated and acylated anthocyanin-rich extracts on plasma metabolic profiles of Zucker diabetic fatty rats. The rats were fed with the nonacylated anthocyanin extract from bilberries (NAAB) or the acylated anthocyanin extract from purple potatoes (AAPP) at daily doses of 25 and 50 mg/kg body weight for 8 weeks. 1H NMR metabolomics was used to study the changes in plasma metabolites. A reduced fasting plasma glucose level was seen in all anthocyanin-fed groups, especially in the groups fed with NAAB. Both NAAB and AAPP decreased the levels of branched-chain amino acids and improved lipid profiles. AAPP increased the glutamine/glutamate ratio and decreased the levels of glycerol and metabolites involved in glycolysis, suggesting improved insulin sensitivity, gluconeogenesis, and glycolysis. AAPP decreased the hepatic TBC1D1 and G6PC messenger RNA level, suggesting regulation of gluconeogenesis and lipogenesis. This study indicated that AAPP and NAAB affected the plasma metabolic profile of diabetic rats differently. </p

Postprandial effects and metabolism of acylated anthocyanins originating from purple potatoes

Healthy dietary choices, such as daily consumption of vegetables and fruits, are fundamental for preventing metabolic disorders. Anthocyanin-rich purple and red edible plants, such as berries and fruits, show potential in improving carbohydrate metabolism. The large diversity of structural characteristics of anthocyanins, such as the number and position of hydroxy, methoxy, glycosyl and acyl substituents, affect their physico-chemical properties and followingly, their absorption and metabolism. However, the health outcomes and metabolism of anthocyanins have been studied mainly with foods rich in non-acylated anthocyanins. Acylated anthocyanins, instead, provide enhanced structural stability for the otherwise unstable anthocyanins and thus have the potential to increase the use of anthocyanins in food industrial applications. Acylated anthocyanins are commonly found in pigmented vegetables and tubers, such as potatoes, which may provide an affordable dietary source of anthocyanins that are easily incorporated into an everyday diet for increased intake of anthocyanins. The aim of the current work was to investigate the in vivo effect of acylated anthocyanins on postprandial glycaemia, insulinaemia and inflammation, and to investigate the metabolism of acylated anthocyanins in healthy volunteers. A pigmented potato variety (Solanum tuberosum L. ′Synkeä Sakari′) with purple skin and flesh was chosen as the model food for these studies since it has a high content of acylated anthocyanins rich in methoxysubstituted B-rings. Furthermore, potatoes are widely consumed and cultivated worldwide and have a high glycaemic index. In two cross-over clinical trials, healthy volunteers consumed a study meal of cooked and mashed purple potatoes or their extract rich in acylated anthocyanins mixed with yellow potatoes, with cooked and mashed yellow potatoes as the control meal. The meals were characterised using high-performance liquid chromatography (HPLC), gas chromatography (GC) and mass spectrometry (MS). The plasma glucose, insulin and 90 inflammation markers were measured. The phenolic metabolites and their phase II conjugates from serially collected plasma and urine samples were screened using UHPLCMS/MS. Both the purple potatoes and the anthocyanin-rich purple potato extract decreased the highest peak of postprandial blood glucose levels as compared to a meal of yellow potatoes. The anthocyanin-rich extract prevented glucose and insulin levels of plasma from decreasing below their fasting state levels, which occurred with the yellow potato meal. Additionally, the anthocyanin-rich extract altered the inflammation markers; for example, the insulin-like FGF-19 was increased four hours after the meal compared to the control meal. These observed health effects may have been affected by postprandial degradants of the ingested acylated anthocyanins, as the parent compounds were not detected in the plasma or urine samples. Instead, a large diversity of phenolic metabolites, such as hydroxycinnamic and hydroxybenzoic acids, were detected. Furthermore, the degradants were subjected to conjugation in phase II metabolism. Several metabolites previously not detected after a meal rich in acylated anthocyanins were identified, such as protocatechuic acid sulfates and glucuronides. This work provides evidence that purple potatoes and their extract rich in acylated anthocyanins affect postprandial carbohydrate metabolism and inflammation beneficially after a high carbohydrate meal. The results shed light on the metabolism of acylated anthocyanins, phenolic metabolites in postprandial state, and promote the use of anthocyanin-rich purple potatoes as a part of a healthy and versatile diet.Terveellinen ruokavalio, kuten runsas kasvisten ja vihannesten nauttiminen, edesauttaa aineenvaihdunnan häiriöiden ennaltaehkäisemisessä. Aiemmat tutkimukset osoittavat, että violeteilla ja punaisilla antosyaniineja sisältävillä syötävillä kasveilla, kuten marjoilla ja hedelmillä, saattaa olla hiilihydraattiaineenvaihdunnalle edullisia terveysvaikutuksia. Antosyaniinit ovat kuitenkin rakenteellisesti monipuolinen yhdisteryhmä, jonka hydroksyyli-, metoksi-, sokeri- ja asyylisubstituentit vaikuttavat niiden fysikokemiallisiin ominaisuuksiin ja siten niiden imeytymiseen ja aineenvaihduntaan. Asyloitujen antosyaniinien vaikutusta ihmisen aterianjälkeiseen aineenvaihduntaan on tutkittu vain vähän, vaikka ne soveltuvat asyloimattomia antosyaniineja pysyvämpinä yhdisteinä paremmin elintarviketeollisuuden tuoteinnovaatioihin. Asyloituja antosyaniineja on runsaasti värillissä juureksissa ja mukuloissa, kuten perunoissa, joita hyödyntämällä on mahdollisuus lisätä antosyaniinien saantia edullisesti ja yksinkertaisesti osana päivittäistä ruokavaliota. Väitöskirjan kokeellisessa osassa tutkittiin asyloitujen antosyaniinien vaikutusta aterianjälkeiseen glykemiaan, insulinemiaan ja tulehdukseen sekä asyloitujen antosyaniinien pilkkoutumista terveiden ihmisten aineenvaihdunnassa. Asyloitujen antosyaniinien elintarvikelähteeksi valittiin violettimaltoinen ja -kuorinen perunalajike (Solanum tuberosum L. ′Synkeä Sakari′), koska sen antosyaniinit ovat valtaosin asyloituja. Lisäksi perunaa käytetään ja viljellään maailmanlaajuisesti, ja niillä on pääsääntöisesti korkea glykeeminen indeksi. Tässä työssä järjestettiin kaksi yksöissokotettua kliinistä vaihtovuorotutkimusta, joissa terveet tutkimushenkilöt nauttivat kypsennettyjä ja soseutettuja violetteja perunoita tai violettien perunoiden antosyaniinipitoista uutetta sekoitettuna soseutettuihin keltamaltoisiin perunoihin. Kontrolliateriana tutkimushenkilöille annettiin kypsennettyjä ja soseutettuja keltamaltoisia perunoita. Tutkimusaterioiden kemiallinen koostumus määritettiin käyttämällä korkean erotuskyvyn nestekromatografiaa (HPLC), kaasukromatografiaa (GC) ja massaspektrometriaa (MS). Tutkimushenkilöiltä kerätyistä plasmanäytteistä määritettiin veren glukoosi- ja insuliinipitoisuudet ja 90 tulehdusmerkkiainetta. Virtsa- ja verinäytteistä selvitettiin fenolisia aineenvaihduntatuotteita (UHPLC-MS/MS). Sekä violetit perunat että niiden antosyaniinipitoinen uute laskivat aterianjälkeistä korkeinta glukoosi- ja insuliinihuippua keltaisiin perunoihin verrattuna. Uute esti kontrolliaterian aiheuttaman glukoosi- ja insuliinipitoisuuksien laskemisen paastotason alapuolelle. Lisäksi uute vaikutti aterianjälkeisiin tulehdusmerkkiaineisiin. Esimerkiksi insuliininkaltaisen FGF- 19:n pitoisuus kasvoi neljä tuntia aterian jälkeen kontrolliateriaan verrattuna. Havaittuihin terveysvaikutuksiin saattoi vaikuttaa asyloitujen antosyaniinien lisäksi niiden aterianjälkeiset hajoamistuotteet, koska perunan antosyaniineja ei havaittu sellaisinaan plasmasta tai virtsasta. Sen sijaan tutkimuksessa havaittiin runsaasti erilaisia fenolisia aineenvaihduntatuotteita, kuten hydroksikanelihappoja ja hydroksibentsoehappoja. Lisäksi aineenvaihduntatuotteisiin saatettiin konjugoida faasin II metaboliassa. Työssä tunnistettiin aineenvaihduntatuotteita, kuten protokatekiinihappoa ja sen konjugaatteja, joita ei oltu aiemmin havaittu pääosin asyloituja antosyaniineja sisältäneen aterian jälkeen. Väitöskirjatutkimus antaa viitteitä siitä, että violeteilla perunoilla ja niiden asyloituja antosyaniineja sisältävällä uutteella on myönteinen vaikutus ihmisen aterianjälkeiseen aineenvaihduntaan ja tulehdukseen runsashiilihydraattisen aterian jälkeen. Tulokset kuvaavat asyloitujen antosyaniinien pilkkoutumista ja fenolisia aineenvaihduntatuotteita aterianjälkeisessä tilassa. Lisäksi tutkimustulokset kannustavat violettimaltoisten perunoiden käyttöön osana terveellistä ja monipuolista ruokavaliota

Effect of processing of bovine milk on gastrointestinal symptoms and intestinal pressure in sensitive individuals

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