Dorota Szawara-Nowak

Changes in the content and composition of anthocyanins in red cabbage and its antioxidant capacity during fermentation, storage and stewing.

The effect of fermentation, storage and stewing on the content and composition of anthocyanins as well as antioxidant capacity of red cabbage was studied. The observation of anthocyanins profile by HPLC-DAD-MS/MS was conducted. Red cabbage products contained twenty different nonacylated and acylated anthocyanins with main structure of cyanidin-3-diglucoside-5-glucoside. Treatments applied affected concentration and profile of red cabbage anthocyanins. Anthocyanins content was reduced by 24%, 25% and 34% in fermented and stewed (30 and 60-min) red cabbage, respectively. The intensity of anthocyanins degradation during storage depended on the process length. Derivatives of cyanidin-3-diglucoside-5-glucoside acylated with sinapic acid were characterised by the highest losses. Five assays were used to analysis of antioxidant capacity. Fresh red cabbage had stronger antioxidant capacity in comparison to fermented, stored and stewed red cabbage. The study has shown that red cabbage products are valuable vegetables for daily consumption in fresh, fermented, stored as well as stewed form.

The impact of red cabbage fermentation on bioavailability of anthocyanins and antioxidant capacity of human plasma.

The effect of red cabbage fermentation on anthocyanin bioavailability and plasma antioxidant capacity in humans was studied. In a randomized crossover study, 13 volunteers consumed fresh and fermented red cabbage. Blood and urine samples were collected before and after consumption. Analyses of anthocyanins by HPLC-MS/MS and plasma antioxidant capacity by photochemiluminescence assay were conducted. Red cabbage products contained 20 different nonacylated and acylated anthocyanins with the main structure of cyanidin triglucosides. The anthocyanins ingested were present in physiological fluids in form of 18 native anthocyanins and 12 metabolites (methylated, glucuronided, sulfated). Among cyanidin metabolites identified, methylated forms were predominant. Bioavailability of anthocyanin from fresh red cabbage was over 10% higher than from fermented red cabbage. Upon fresh cabbage consumption, volunteers plasma showed higher antioxidant capacity than after fermented cabbage intake. The study has shown that fermentation process affects red cabbage anthocyanins bioavailability and human plasma antioxidant capacity.

Antioxidative and Anti-Glycation Activity of Buckwheat Hull Tea Infusion

The utilization of buckwheat hull for the preparation of buckwheat hull tea was addressed in this study. The total phenolics content, flavonoids profile, antioxidant capacity, and anti-glycation activity of buckwheat hull tea were compared to those of green tea. The buckwheat hull contained rutin, quercetin, and C-glucoflavones; however, the total phenolic content was significantly lower in comparison to green tea leaves. Rutin and vitexin were the main flavonoids found in buckwheat hull tea. The buckwheat hull tea showed lower antioxidant capacity and inhibitory activity against the formation of fluorescent advanced glycation end products as compared to green tea.

Quercetin and isorhamnetin aglycones are the main metabolites of dietary quercetin in cerebrospinal fluid

SCOPE Reports on the protective effect of certain foods on brain functions are numerous; however, the permeability of the brain barriers by food components is still hardly recognised. There have been in vitro studies aimed at demonstrating this possibility, but not much is known about this phenomenon in in vivo systems. The objective of the study was to determine the metabolites of dietary quercetin (Q) in urine, blood plasma and cerebrospinal fluid (CSF) after intra-rumen administration of Q rich onion dry skin in an animal model. METHODS AND RESULTS Eleven sheep had permanently implanted cannulas in the third ventricle of the brain as the means for CSF collection. The animals were administered Q at the dose of 10 mg/kg bwt. For 12 h the concentration of Q metabolites was measured in urine, blood plasma, and CSF. It was demonstrated that while in blood plasma Q and isorhamnetin mono-glucuronides or mono-sulphates were the main metabolites (80%), in CSF their aglycones were the dominating ones (88%). CONCLUSION Q and IR aglycones are the main Q metabolites present in CSF after dietary Q intake. Their passive transport through blood-CSF barrier or a de-conjugating mechanism within that barrier may be involved.

Buckwheat bioactive compounds, their derived phenolic metabolites and their health benefits.

SCOPE Buckwheat (BW) consumption has been associated with a broad range of health benefits: antioxidant, anti-inflammatory and anticancer. These beneficial effects have been partially related to the presence of flavonoids. However, some of these compounds (i.e., rutin and quercetin) are metabolized in the gastrointestinal tract generating derived phenolic metabolites. In this study, we investigated the biological activity of rutin (Ru), quercetin (Q) an their derived phenolic metabolites 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), 3-hydroxyphenylacetic acid (3-HPAA), and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid, HVA). METHODS AND RESULTS Q showed the highest antioxidant and reducing activity, and Ru the maximum chelating activity (85.33%). Antioxidant activity of 3,4-DHPAA was 5-fold higher than that of HVA, whereas their reducing activity was similar. The formation of methylglyoxal (MGO)-BSA and glucose-BSA (advanced glycation end products) was inhibited by Ru (98.5 and 92.7%), Q (95.6 and 89.1%) and 3,4-DHPPA (84.4.6 and 77.5%). Furthermore, Q (10-50 μM) and Ru (1-50 μM) downregulated the release of PGE2 , IL-8 and MCP-1, molecules involved in the inflammatory response, in IL1β-inflamed myofibroblasts of colon CCD-18Co. CONCLUSION This study suggests that BW phytochemicals and their phenolic metabolites may be responsible for the beneficial effects against chronic diseases attributed to BW consumption.

Profile of Phenolic Acids and Antioxidant Capacity in Organs of Common Buckwheat Sprout

The aim of the study was to analyse the content of phenolic acids, total phenolic compounds, proanthocyanidins, and antioxidant capacity in cotyledons and hypocotyl of five cultivars of common buckwheat (Fagopyrum esculentum Moench) sprout. This study presents the first broad profile of phenolic acids occurring in buckwheat microgreen seedlings. In the hypocotyl and cotyledons trans-cinnamic acid and its derivatives: o-, m-, and p-coumaric acids (2-, 3-, and 4-hydroxycinnamic), synapic acid (4-hydroxy-3,5-dimethoxycinnamic), caffeic acid (3,4-dihydroxycinnamic), and two isomers of ferulic acid (4-hydroxy-3-methoxycinnamic and 3-hydroxy-4-methoxycinnamic) have been identified. Among the benzoic acid derivatives hydroxybenzoic, protocatechuic (3,4-dihydroxybenzoic), gallic (3,4,5-dihydroxybenzoic) and syringic (4-hydroxy-3,5-dimethoxybenzoic) were found in the organs. In addition to those mentioned, the organs of buckwheat sprouts contain chlorogenic acid as well. The contents of all analysed phenolics were...

Methyl jasmonate stimulates biosynthesis of 2-phenylethylamine, phenylacetic acid and 2-phenylethanol in seedlings of common buckwheat

Methyl jasmonate has a strong effect on secondary metabolizm in plants, by stimulating the biosynthesis a number of phenolic compounds and alkaloids. Common buckwheat (Fagopyrum esculentum Moench) is an important source of biologically active compounds. This research focuses on the detection and quantification of 2-phenylethylamine and its possible metabolites in the cotyledons, hypocotyl and roots of common buckwheat seedlings treated with methyl jasmonate. In cotyledons of buckwheat sprouts, only traces of 2-phenylethylamine were found, while in the hypocotyl and roots its concentration was about 150 and 1000-times higher, respectively. Treatment with methyl jasmonate resulted in a 4-fold increase of the 2-phenylethylamine level in the cotyledons of 7-day buckwheat seedlings, and an 11-fold and 5-fold increase in hypocotyl and roots, respectively. Methyl jasmonate treatment led also to about 4-fold increase of phenylacetic acid content in all examined seedling organs, but did not affect the 2-phenylethanol level in cotyledons, and slightly enhanced in hypocotyl and roots. It has been suggested that 2-phenylethylamine is a substrate for the biosynthesis of phenylacetic acid and 2-phenylethanol, as well as cinnamoyl 2-phenethylamide. In organs of buckwheat seedling treated with methyl jasmonate, higher amounts of aromatic amino acid transaminase mRNA were found. The enzyme can be involved in the synthesis of phenylpyruvic acid, but the presence of this compound could not be confirmed in any of the examined organs of common buckwheat seedling.

Effect of fermented and unfermented buckwheat flour on functional properties of gluten-free muffins

Selected functional properties of four types of gluten-free muffins made of unfermented and fermented (by Lactobacillus plantarum) buckwheat flour in comparison with control muffins made using commercial gluten-free corn flour were evaluated in this study. The proximate chemical composition, antioxidant capacity analysed by ABTS, photochemiluminescence and cyclic voltammetry assays, and inhibitory activity against protein glycation in vitro in BSA/Glu systems were investigated. The content of the total phenolic compounds, available lysine, furosine, free and total FIC, browning index and antioxidant capacity of buckwheat-enhanced gluten-free muffins were higher compared to the control samples. Gluten-free muffins made of the fermented buckwheat flour showed a significantly higher antioxidant capacity, an increased activity against AGEs formation and an increased available lysine content, as well as a higher FAST index and browning index as compared to the muffins obtained with unfermented buckwheat flour. The study showed that buckwheat flour fermented by L. plantarum could be used as an ingredient for improving the functional properties of gluten-free muffins.

Effect of liquid-state fermentation on the antioxidant and functional properties of raw and roasted buckwheat flours

The influence of liquid-state fermentation (LSF) by selected lactic acid bacteria (LAB) and Rhizopus oligosporus fungi on the content of rutin and total phenolic compounds (TPC), antioxidant capacity measured by ABTS test, FRAP assay and photochemiluminescence technique, and the inhibitory activity against formation of fluorescent advanced glycation end-products (AGEs) in vitro of raw and roasted buckwheat flours was studied. LSF caused a slight, specific LAB-dependent increase in TPC and a decrease in rutin content. Fermented raw buckwheat flours contained higher amounts of rutin and TPC with one exception when the highest increase in TPC was noted in roasted flour fermented by fungi. A LAB-dependent difference in the antioxidant capacity of buckwheat flours was noted while the inhibitory activity of fermented flours against AGEs formation was generally reduced. It can be concluded that LSF with selected LAB and fungi may improve the antioxidant and functional properties of buckwheat flours.

Interlaboratory Coverage Test on Plant Food Bioactive Compounds and Their Metabolites by Mass Spectrometry-Based Untargeted Metabolomics

Bioactive compounds present in plant-based foods, and their metabolites derived from gut microbiota and endogenous metabolism, represent thousands of chemical structures of potential interest for human nutrition and health. State-of-the-art analytical methodologies, including untargeted metabolomics based on high-resolution mass spectrometry, are required for the profiling of these compounds in complex matrices, including plant food materials and biofluids. The aim of this project was to compare the analytical coverage of untargeted metabolomics methods independently developed and employed in various European platforms. In total, 56 chemical standards representing the most common classes of bioactive compounds spread over a wide chemical space were selected and analyzed by the participating platforms (n = 13) using their preferred untargeted method. The results were used to define analytical criteria for a successful analysis of plant food bioactives. Furthermore, they will serve as a basis for an optimized consensus method.