Compelling evidence of the health benefits of phenolic compounds and their impact on food quality have stimulated the development of analytical methods for the identification and quantification of ...these compounds in different matrices in recent years. A targeted metabolomics method has been developed for the quantification of 135 phenolics, such as benzoates, phenylpropanoids, coumarins, stilbenes, dihydrochalcones, and flavonoids, in fruit and tea extracts and wine using UPLC/QqQ-MS/MS. Chromatography was optimized to achieve separation of the compounds over a period of 15 min, and MRM transitions were selected for accurate quantification. The method was validated by studying the detection and quantification limits, the linearity ranges, and the intraday and interday repeatability of the analysis. The validated method was applied to the analysis of apples, berries, green tea, and red wine, providing a valuable tool for food quality evaluation and breeding studies.
Accurate quantification and structural characterization of ellagitannins and ellagic acid conjugates in food, beverages, and food supplements are essential starting points for studying their effect ...on human health. However, accuracy is hindered both by the lack of pure standard compounds and by methods that maintain the compounds in their native form, avoiding any chemical modification of the structure. The objective of this work was to develop a new method for the purification, chromatographic separation, and accurate quantification of ellagitannins and ellagic acid conjugates to provide thorough characterization of the diversity in composition of 11 Rubus cultivars grown in Trentino, Italy. As such, two major steps were required: (i) the isolation and purification (with associated detailed structural characterization and determination of their molar extinction coefficients) of sanguiin H-6 and lambertianin C, providing essential data for their use, together with ellagic acid, as external standards, and (ii) the determination of the chemical structure of 20 novel minor ellagitannins and 4 ellagic acid conjugates on the basis of their Q-TOF-HDMS and DAD spectra. This survey of ellagitannins and ellagic acid conjugates provides evidence for the existence of significant differences in the pattern between and within blackberry and raspberry cultivars. To our knowledge, this is the first paper that has combined detailed metabolite profiling with accurate quantification of the main ellagitannins in Rubus using their respective standards.
Ellagitannins have shown anti-inflammatory and anti-Helicobacter pylori properties; however, their anti-inflammatory activity at gastric level was not previously investigated. The aim of this ...research was to evaluate the effects of ellagitannins from Rubus berries on gastric inflammation. Ellagitannin enriched extracts (ETs) were prepared from Rubus fruticosus L. (blackberry) and Rubus idaeus L. (raspberry). The anti-inflammatory activity was tested on gastric cell line AGS stimulated by TNF-α and IL-1β for evaluating the effect on NF-kB driven transcription, nuclear translocation and IL-8 secretion. In vivo the protective effect of ellagitannins was evaluated in a rat model of ethanol-induced gastric lesions. Rats were treated orally for ten days with 20 mg/kg/day of ETs, and ethanol was given one hour before the sacrifice. Gastric mucosa was isolated and used for the determination of IL-8 release, NF-kB nuclear translocation, Trolox equivalents, superoxide dismutase and catalase activities. In vitro, ETs inhibited TNF-α induced NF-kB driven transcription (IC₅₀: 0.67-1.73 µg/mL) and reduced TNF-α-induced NF-kB nuclear translocation (57%-67% at 2 µg/mL). ETs inhibited IL-8 secretion induced by TNF-α and IL-1β at low concentrations (IC₅₀ range of 0.7-4 µg/mL). Sanguiin H-6 and lambertianin C, the major ETs present in the extracts, were found to be responsible, at least in part, for the effect of the mixtures. ETs of blackberry and raspberry decreased Ulcer Index by 88% and 75% respectively and protected from the ethanol induced oxidative stress in rats. CINC-1 (the rat homologue of IL-8) secretion in the gastric mucosa was reduced in the animals receiving blackberry and raspberry ETs. The effect of ETs on CINC-1 was associated to a decrease of NF-κB nuclear translocation in ETs treated animals. The results of the present study report for the first time the preventing effect of ETs in gastric inflammation and support for their use in dietary regimens against peptic ulcer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•A total of 56 polyphenols were accurately quantified in a bowl of strawberries.•Detailed de novo identification of some strawberry polyphenols.•Precise estimation of strawberry composition for ...nutritional studies was achieved.
Strawberry (Fragaria × ananassa Duch.) is an important source of polyphenols in the human diet, and is considered a functional food. However, at the moment, it is not fully understood which compounds are involved. The aim was to present a comprehensive picture of the amount of polyphenols present in strawberry. A total of 56 individual compounds were identified and quantified with a triple-quadrupole mass spectrometer, their concentration ranging from 1 µg/100 g to 40 mg/100 g of fresh fruit. Furthermore, spectrophotometric assay for estimation of high-molecular mass proanthocyanidins was applied. Several compounds were identified/quantified for the first time.
Ellagitannins and ellagic acid conjugates are polyphenols present in the human diet, in particular strawberries (Fragaria spp.). The first aim of this study was isolation and structural ...characterization of casuarictin and 3-O-methyl ellagic acid 3′-O-α-rhamnopyranoside, which were found to be abundant in Fragaria spp., along with agrimoniin. The second aim was accurate profiling and quantification of 26 ellagitannins and ellagic acid conjugates in six Fragaria x ananassa cultivars and two Fragaria vesca species. The third aim was to describe the ellagitannins behavior during fruit ripening from the green stage to over-ripeness. It was shown that there are major qualitative and quantitative differences in the amount and profile of ellagitannins and ellagic acid conjugates between Fragaria spp. Genotype is a major factor in defining ellagitannin concentration and patterns between strawberries, and variable behavior of the genotypes was observed, in the context of a significant drop in ellagitannins during ripening.
Display omitted
In the present study we chemically profiled tannin-enriched extracts from strawberries and tested their biological properties in a cell model of gastric inflammation. The chemical and ...biological features of strawberry tannins after in vitro simulated gastric digestion were investigated as well. The anti-inflammatory activities of pure strawberry tannins were assayed to get mechanistic insights.
Tannin-enriched extracts from strawberries inhibit IL-8 secretion in TNFα-treated human gastric epithelial cells by dampening the NF-κB signaling. In vitro simulated gastric digestion slightly affected the chemical composition and the biological properties of strawberry tannins. By using pure compounds, we found that casuarictin may act as a pure NF-κB inhibitor while agrimoniin inhibits IL-8 secretion also acting on other biological targets; in our system procyanidin B1 prevents the TNFα-induced effects without interfering with the NF-κB pathway.
We conclude that strawberry tannins, even after in vitro simulated gastric digestion, exert anti-inflammatory activities at nutritionally relevant concentrations.
The identification of the missing steps in S-glutathionyl-3-mercaptohexan-1-ol degradation pathways leads to better understanding of the formation of the tropical aroma of yellow passion fruit. ...Display omitted
► New synthetic strategy for the preparation of Glu-Cys-3MH and Cys-Gly-3MH. ► The three missing stages leading to the S-cysteinylated precursor were identified. ► Two intermediates found between S-glutathionyl and S-cysteinyl 3-mercaptohexan-1-ol. ► Demonstrating that the plant is capable of activating both metabolic routes.
Yellow passion fruit is one of the most well-known tropical fruits and much of its success comes from its typical aroma. Key compounds in explaining yellow passion fruit scent are volatile thiols. These molecules are reported to be present in several fruits and originate from non-volatile precursors. Such free thiols are particularly appreciated in white wines and considerable efforts have been made to try to maximise their production and understand their biosynthesis.
Two main precursors have been identified so far: S-glutathionylated and S-cysteinylated precursors, the latter originating in the breaking down of the glycyl and glutamyl moieties of the former. Improving knowledge about this pathway is currently one of the main challenges in the field of aroma chemistry.
Only S-cysteinylated precursors have been reported in the literature for yellow passion fruit, thus much of the biochemical pathway remains unknown.
In this paper a combination of organic synthesis, MS and NMR experiments was developed in order to investigate this pathway in yellow passion fruit. The three missing stages leading to the S-cysteinylated precursor were clearly identified. Both intermediate species between S-glutathionyl and S-cysteinyl 3-mercaptohexan-1-ol were found, suggesting that the plant is capable of activating both metabolic routes.
The information gained would appear to be crucial for study of this important pathway and for potentially extending this knowledge to other plants, in particular the grapevine.
Whole plant foods, including fruit, vegetables, and whole grain cereals, protect against chronic human diseases such as heart disease and cancer, with fiber and polyphenols thought to contribute ...significantly. These bioactive food components interact with the gut microbiota, with gut bacteria modifying polyphenol bioavailability and activity, and with fiber, constituting the main energy source for colonic fermentation. This paper discusses the consequences of increasing the consumption of whole plant foods on the gut microbiota and subsequent implications for human health. In humans, whole grain cereals can modify fecal bacterial profiles, increasing relative numbers of bifidobacteria and lactobacilli. Polyphenol-rich chocolate and certain fruits have also been shown to increase fecal bifidobacteria. The recent FLAVURS study provides novel information on the impact of high fruit and vegetable diets on the gut microbiota. Increasing whole plant food consumption appears to up-regulate beneficial commensal bacteria and may contribute toward the health effects of these foods.
An increasing number of studies have concerned the profiling of polyphenol microbial metabolites, especially in urine or plasma, but only a few have regarded their accurate quantification. This study ...reports on a new ultra-performance liquid chromatography tandem mass spectrometry method with electrospray ionisation (UHPLC–ESI-MS/MS) using a simple clean-up step with solid phase extraction (SPE) and validation on different biological matrices. The method was tested with spiked samples of liver, heart, kidneys, brain, blood and urine.
The purification procedure, after the evaluation of three different cartridges, makes it possible to obtain cleaner samples and better quantification of putative trace metabolites, especially related to dietary studies, with concentrations below ng/g in tissue and for urine and blood, starting from ng/ml. Limits of detection and linear range were also assessed using mixed polyphenol metabolite standards.
Short chromatographic separation was carried out for 23 target compounds related to the polyphenol microbial metabolism, coupled with a triple quadrupole mass spectrometer for their accurate quantification. By analysing different spiked biological samples we were able to test metabolite detection in the matrix and validate the overall recovery of the method, from purification to quantification.
The method developed can be successfully applied and is suitable for high-throughput targeted metabolomics analysis related to nutritional intervention, or the study of the metabolic mechanism in response to a polyphenol-rich diet.
Display omitted
•UHPLC–ESI-MS/MS method development for polyphenol microbial metabolites.•Separation and quantification the 23 metabolites related to fruit consumption.•Solid Phase Extraction for purification of metabolites from biological matrix.•Application and validation of the method to 4 tissues and 2 biological fluids.
Different polyphenol compounds are ingested when consuming a serving of fruits rich in polyphenols, spanning from one-phenol hydroxybenzoic acid to more complex polymeric compounds. Only a minor ...quantity of the polyphenols (5–10%) is absorbed. The remainder reaches the colon and is extensively metabolized by gut microbiota to low-molecular weight metabolites. Their subsequent tissue distribution is still undefined, although these microbial metabolites are currently believed to play a role in human health and disease states. To fill this knowledge gap, we performed a pharmacokinetics experiment in which a single bolus of 23 polyphenol microbial metabolites (total 2.7 μmol) was administered intravenously to rats to reliably reproduce a physiological postabsorption situation. Tissues and urine were collected shortly thereafter (15 s to 15 min) and were analyzed by UHPLC-MS/MS to quantitatively track these compounds. Remarkably, the brain was found to be a specific target organ for 10 of the 23 polyphenol metabolites injected, which significantly increased in the treated animals. In most cases, their appearance in the brain was biphasic, with an early wave at 2 min (4 compounds) and a second wave starting at 5 min; at 15 min, 9 compounds were still detectable. Most compounds were excreted into the urine. The concentrations in the brain of the treated animals were compared against those of the control group by Student’s t test, with p-values < 0.1 considered to be statistically significant. These findings provide new perspectives for understanding the role of diet on brain chemistry. Our experimental approach has enabled us to obtain rich metabolomics information from a single experiment involving a limited number of animals.
PDF
