Postprandial Micronutrient Variability and Bioavailability: An Interventional Meal Study in Young vs. Old Participants.

This study explores age- and time-dependent variations in postprandial micronutrient absorption after a micronutrient-rich intervention meal within the Biomiel (bioavailability of micronutrients in elderly) study. Comprising 43 healthy participants, the study compares young (n = 21; mean age 26.90 years) and old (n = 22; mean age 66.77 years) men and women, analyzing baseline concentrations and six-hour postprandial dynamics of iron (Fe), copper (Cu), zinc (Zn), selenium (Se), iodine (I), free zinc (fZn), vitamin C, retinol, lycopene, ß-carotene, α-tocopherol, and γ-tocopherol, along with 25(OH) vitamin D (quantified only at baseline). Methodologically, quantifications in serum or plasma were performed at baseline and also at 90, 180, 270, and 360 min postprandially. Results reveal higher baseline serum Zn and plasma lycopene concentrations in the young group, whereas Cu, Se, Cu/Zn ratio, 25(OH) vitamin D, α-tocopherol, and γ-tocopherol were higher in old participants. Postprandial variability of Zn, vitamin C, and lycopene showed a strong time-dependency. Age-related differences in postprandial metabolism were observed for Se, Cu, and I. Nevertheless, most of the variance was explained by individuality. Despite some limitations, this study provides insights into postprandial micronutrient metabolism (in serum/plasma), emphasizing the need for further research for a comprehensive understanding of this complex field. Our discoveries offer valuable insights for designing targeted interventions to address and mitigate micronutrient deficiencies in older adults, fostering optimal health and well-being across the lifespan.

Comprehensive analysis of pigment alterations and associated flavor development in strip and needle green teas.

Strip/needle green teas (SGT/NGT) processed using innovative technologies are in high demand; however, mechanisms behind their color and flavor have not been comprehensively studied. We aimed to reveal the dynamics of major pigmented components (carotenoids, lipids, flavonoids, and Maillard products) and their contributions to the flavor of green teas. The total content of flavonoids in SGT and NGT were 255 ± 4.51 and 201 ± 3.91 mg·g-1, respectively; these values are slightly lower than that in fresh leaves (FLs), resulting in a fresh and sweet aftertaste. In average, carotene content in SGT/NGT (24.8 µg·g-1) was higher than in FL (17.4 µg·g-1), whilst xanthophyll content (603 µg·g-1) decreased to one-half of that in FL (310 µg·g-1). Among the 218 primary metabolites, glutamine, glutamic acid, and arginine were found to accumulate and were dominate contributors for the umami and sweet taste. Notably, more than 96 volatiles were screened and revealed their correlations with carotenoids, lipids, and amino acids. Overall, the synergism between pigments and their non-enzymatic derivates' contribution to GT characterized flavor was illustrated.

Brassica-enriched wheat bread: Unraveling the impact of ontogeny and breadmaking on bioactive secondary plant metabolites of pak choi and kale.

Consumption of Brassica vegetables is linked to health benefits, as they contain high concentrations of the following secondary plant metabolites (SPMs): glucosinolate breakdown products, carotenoids, chlorophylls, and phenolic compounds. Especially Brassica vegetables are consumed as microgreens (developed cotyledons). It was investigated how different ontogenetic stages (microgreens or leaves) of pak choi (Brassica rapa subsp. chinensis) and kale (Brassica oleracea var. sabellica) differ in their SPM concentration. The impact of breadmaking on SPMs in microgreens (7 days) and leaves (14 days) in pak choi and kale as a supplement in mixed wheat bread was assessed. In leaves, carotenoids, chlorophylls, and phenolic compounds were higher compared to those of microgreens. Breadmaking caused a decrease of SPMs. Chlorophyll degradation was observed, leading to pheophytin and pyropheophytin formation. In kale, sinapoylgentiobiose, a hydroxycinnamic acid derivative, concentration increased. Thus, leaves of Brassica species are suitable as natural ingredients for enhancing bioactive SPM concentrations in bread.

African Nightshade (Solanum scabrum Mill.): Impact of Cultivation and Plant Processing on Its Health Promoting Potential as Determined in a Human Liver Cell Model.

Plant cultivation and processing may impact nutrient and phytochemical content of vegetables. The present study aimed at determining the influence of cultivation and processing on the health promoting capacity of African nightshade (Solanum scabrum Mill.) leaves, an indigenous vegetable, rich in nutrients and phytochemicals. Anti-genotoxicity against the human liver carcinogen aflatoxin B1 (AFB1) as determined by the comet assay and radical oxygen species (ROS) scavenging capacity of ethanolic and aqueous extracts were investigated in human derived liver (HepG2) cells. ROS scavenging activity was assessed using electron paramagnetic spin resonance and quantification of ARE/Nrf2 mediated gene expression. The cultivation was done under different environmental conditions. The processing included fermentation and cooking; postharvest ultraviolet irradiation (UV-C) treatment was also investigated. Overall, S. scabrum extracts showed strong health promoting potential, the highest potential was observed with the fermented extract, which showed a 60% reduction of AFB1 induced DNA damage and a 38% reduction in FeSO4 induced oxidative stress. The content of total polyphenols, carotenoids and chlorophylls was indeed affected by cultivation and processing. Based on the present in vitro findings consumption of S. scabrum leaves could be further encouraged, preferentially after cooking or fermentation of the plant.

Diverse Excretion Pathways of Benzyl Glucosinolate in Humans after Consumption of Nasturtium (Tropaeolum majus L.)-A Pilot Study.

SCOPE: Different metabolic and excretion pathways of the benzyl glucosinolate breakdown products benzyl isothiocyanate and benzyl cyanide are investigated to obtain information about their multiple fate after ingestion. Detailed focus is on the so far underestimated transformation/excretion pathways-protein conjugation and exhalation. METHODS AND RESULTS: Metabolites, protein conjugates, and non-conjugated isothiocyanates are determined in plasma, urine, and breath of seven volunteers after consuming freeze-dried nasturtium or bread enriched with nasturtium. Samples are collected up to 48 h at selected time points. The metabolites of the mercapturic acid pathway are detectable in plasma up to 24 h after consumption. Additionally, mercapturic acid is the main metabolite in urine, but non-conjugated benzyl isothiocyanate is detectable as well. Protein conjugates show high amounts in plasma even 48 h after consumption. In breath, benzyl isothiocyanate and benzyl cyanide are detectable up to 48 h after consumption. CONCLUSION: Isothiocyanates are not only metabolized via the mercapturic acid pathway, but also form protein conjugates in blood and are exhaled. To balance intake and excretion, it is necessary to investigate all potential metabolites and excretion routes. This has important implications for the understanding of physiological and pharmacological effects of isothiocyanate-containing products.

Natural diversity of hydroxycinnamic acid derivatives, flavonoid glycosides, carotenoids and chlorophylls in leaves of six different amaranth species.

Amaranth species are globally grown food crops. However, knowledge about the composition of their secondary metabolites is insufficient. Here, selected hydroxycinnamic acid derivatives, flavonoid glycosides, carotenoids and chlorophylls in the leaves of 14 genotypes from six different amaranth species were identified and quantified. For the first time, caffeic acid esters of isocitric and several aldaric acids were isolated and quantified in a leafy food matrix. High concentrations of hydroxycinnamic acid derivatives and chlorophylls, and moderate amounts of flavonoids and carotenoids were detected. A hierarchical clustering method of the metabolic profiles followed by Random Amplification of Polymorphic DNA (RAPD)-PCR fingerprinting was used to group the genotypes. Using this combined approach, three main groups of amaranth species were assigned. The information provided in this study increases the attractiveness of the amaranth genus as a food crop due to its strong diversity of plant secondary metabolites that are associated with numerous health-promoting benefits.

Indigenous leafy vegetables of Eastern Africa - A source of extraordinary secondary plant metabolites.

Indigenous African leafy vegetables vary enormously in their secondary plant metabolites whereat genus and the species have a great impact. In African nightshade (Solanum scabrum), spiderplant (Cleome gynandra), amaranth (Amaranthus cruentus), cowpea (Vigna unguiculata), Ethiopian kale (Brassica carinata) and common kale (Brassica oleracea) the specific secondary metabolite profile was elucidated and gained detailed data about carotenoids, chlorophylls, glucosinolates and phenolic compounds all having an appropriate contribution to health beneficial properties of indigenous African leafy vegetables. Exemplarily, various quercetin glycosides such as quercetin-3-rutinoside occur in high concentrations in African nightshade, spiderplant, and amaranth between ~1400-3300µg/g DW. Additionally the extraordinary hydroxycinnamic acid derivatives such as glucaric isomers and isocitric acid isomers are found especially in amaranth (up to ~1250µg/g DW) and spiderplant (up to 120µg/g DW). Carotenoids concentrations are high in amaranth (up to101.7µg/g DW) and spiderplants (up to 64.7µg/g DW) showing high concentrations of ß-carotene, the pro-vitamin A. In contrast to the ubiquitous occurring phenolics and carotenoids, glucosinolates are only present in the Brassicales species Ethiopian kale, common kale and spiderplant characterized by diverse glucosinolate profiles. Generally, the consumption of a variety of these indigenous African leafy vegetables can be recommended to contribute to different benefits such as antioxidant activity, increase pro-vitamin A and anticancerogenic compounds in a healthy diet.

Evaluation of an Aqueous Extract from Horseradish Root (Armoracia rusticana Radix) against Lipopolysaccharide-Induced Cellular Inflammation Reaction.

Horseradish (Armoracia rusticana) is a perennial crop and its root is used in condiments. Traditionally, horseradish root is used to treat bacterial infections of the respiratory tract and urinary bladder. The antiphlogistic activity, determined in activated primary human peripheral blood mononuclear cells (PBMC), was evaluated for an aqueous extract and its subfractions, separated by HPLC. Compound analysis was done by UHPLC-QToF/MS and GC-MS. The aqueous extract concentration-dependently inhibited the anti-inflammatory response to lipopolysaccharide (LPS) in terms of TNF-α release at ≥37 µg/mL. Further, the cyclooxygenase as well as lipoxygenase pathway was blocked by the extract as demonstrated by inhibition of COX-2 protein expression and PGE2 synthesis at ≥4 µg/mL and leukotriene LTB4 release. Mechanistic studies revealed that inhibition of ERK1/2 and c-Jun activation preceded COX-2 suppression upon plant extract treatment in the presence of LPS. Chemical analysis identified target compounds with a medium polarity as relevant for the observed bioactivity. Importantly, allyl isothiocyanate, which is quite well known for its anti-inflammatory capacity and as the principal pungent constituent in horseradish roots, was not relevant for the observations. The results suggest that horseradish root exerts an antiphlogistic activity in human immune cells by regulation of the COX and LOX pathway via MAPK signalling.

Nasturtium (Indian cress, Tropaeolum majus nanum) dually blocks the COX and LOX pathway in primary human immune cells.

BACKGROUND: Nasturtium (Indian cress, Tropaeolum majus) is known for its pharmacological value in the treatment of bacterial infections of the upper air tract and urinary bladder. However, scientific data on the anti-inflammatory potency in human-derived cells is missing. PURPOSE: The aim of this study was to investigate the potential of nasturtium to inhibit the lipopolysaccharide (LPS) induced inflammatory response in primary human cells of the immune system. STUDY DESIGN: The anti-inflammatory activities of nasturtium and its fractions were evaluated via regulation of arachidonic acid (AA) pathway and MAPK kinase cascade. Fraction H4 which was responsible for the anti-inflammatory effects was further characterized. METHODS: Human peripheral blood mononuclear cells (PBMC) were either treated with plant extracts or fractions thereof, stimulated with LPS and/or N-formyl-methionyl-leucyl-phenylalanine (fMLP) and analysed for COX and LOX, release of prostaglandin PGE2, leukotriene LTB4, TNF-alpha and ERK signaling pathway activation. The plant extracts were separated into four fractions by HPLC; fraction H4 was subjected to UHPLC-ToF/MS analysis to identify potential bioactive compounds. RESULTS: We found that aqueous extracts of nasturtium did exert strong concentration dependent suppression of LPS-triggered TNF-alpha release and COX pathway signaling, including PGE2 synthesis. Whereas COX-1 protein expression was not impacted, LPS-triggered COX-2 protein expression was concentration dependently blocked by the plant extract but not COX-2 enzyme activity. These findings suggest a mechanism of action for the plant extract which is different from non-steroidal anti-inflammatory drugs (NSAIDs). Moreover, the plant extract blocked leukotriene LTB4 release, the major end product of the 5-LOX pathway from PBMC. Down-regulation of ERK1/2 and c-Jun activation preceded COX-2 suppression upon plant extract treatment in the presence of LPS. Using HPLC separation of the aqueous extract followed by metabolomic analysis we could limit the number of relevant bioactive compounds in the extract to about 50. CONCLUSIONS: This study provides a rationale for the anti-inflammatory efficacy of nasturtium observed in man and gives first insight into the underlying molecular mechanisms.

Characterisation of odorant compounds and their biochemical formation in green tea with a low temperature storage process.

We produced low temperature (15 °C) processed green tea (LTPGT) with higher aroma contents than normal green tea (Sencha). Normal temperature processed green tea (NTPGT), involved storing at 25 °C, and Sencha had no storing process. Sensory evaluation showed LTPGT had higher levels of floral and sweet odorants than NTPGT and Sencha. Aroma extract dilution analysis and gas chromatography-mass spectrometry-olfactometry indicated LTPGT had 12 aroma compounds with high factor dilution values (FD). Amongst LTPGT's 12 compounds, indole, jasmine lactone, cis-jasmone, coumarin, and methyl epijasmonate contributed to floral, fruity and sweet characters. In particular, indole increased initially, peaking at 16 h, then gradually decreased. Feeding experiments suggested [(15)N]indole and [(15)N]oxygenated indoles (OX-indoles) were produced from [(15)N]anthranilic acid. We proposed the increase in indole was due to transformation of anthranilic acid during the 16 h storage and the subsequent decline in indole level was due to its conversion to OX-indoles.

Influence of exogenously applied abscisic acid on carotenoid content and water uptake in flowers of the tea plant (Camellia sinensis).

BACKGROUND: Carotenoids are a major class of plant pigments and fulfill many functions in different organisms that either produce or consume them. Although the color of the stamina of tea (Camellia sinensis) flowers is clearly due to the presence of carotenoids, the carotenoid profile and content remain to be discovered. RESULTS: We investigated the carotenoid profile of tea flowers and determined changes in concentrations over the floral development. The flowers contained oxygenated xanthophylls such as neoxanthin, lutein and zeaxanthin, as well as the hydrocarbons ß-carotene and α-carotene. Flowers of the tea plant contain to vegetables comparable amounts of carotenoids. The content of 9'-cis-epoxycarotenoids, which serve as abscisic acid precursors, as well as changes in concentration of abscisic acid were studied. The concentrations of carotenoids decreased whereas the abscisic acid content increased over the floral development. Exogenously applied S-abscisic acid affected water uptake, flower opening and carotenoid accumulation. CONCLUSION: In summary, this paper reports, for the first time, the carotenoid profile and content of tea flowers. The study revealed that carotenoids in tea flowers are an interesting target in respect of possible applications of tea flower extracts as well as biological functions of abscisic acid during floral development.

Isolation and identification of spermidine derivatives in tea (Camellia sinensis) flowers and their distribution in floral organs.

BACKGROUND: Recently, tea (Camellia sinensis) flowers have attracted increasing interest because of their content of bioactive compounds such as catechins. The aim of this study was to investigate the occurrence of some characteristic compounds in tea flowers. RESULTS: A principal component analysis of metabolites using ultra-performance liquid chromatography/time-of-flight mass spectrometry showed differences in metabolite profile between flowers and leaves of C. sinensis var. Yabukita. Four spermidine derivatives were isolated from tea flowers. One of them was determined as N(1) ,N(5) ,N(10) -tricoumaroyl spermidine based on NMR, MS and UV data. The other three were identified as feruoyl dicoumaroyl spermidine, coumaroyl diferuoyl spermidine and triferuoyl spermidine based on MS(n) data. Tricoumaroyl spermidine as the major spermidine conjugate was not detected in tea leaves. Furthermore, it decreased during floral development and mainly occurred in anthers. CONCLUSION: This study has provided the first evidence that spermidine-phenolic acid conjugates occur in tea flowers in considerable amounts. Their presence should prompt a reconsideration of the ecological role of tea flowers. From an economic point of view, tea flowers might be suitable as a raw material in the healthcare food and pharmaceutical industries.

Characterization of L-phenylalanine metabolism to acetophenone and 1-phenylethanol in the flowers of Camellia sinensis using stable isotope labeling.

Acetophenone (AP) and 1-phenylethanol (1PE) are the two major endogenous volatile compounds in flowers of Camellia sinensis var. Yabukita. Until now no information has been available on the biosynthesis of AP and 1PE in plants. Here we propose that AP and 1PE are derived from L-phenylalanine (L-Phe), based on feeding experiments using stable isotope-labeled precursors L-[(2)H(8)]Phe and L-[(13)C(9)]Phe. The subacid conditions in the flowers result in more hydrogenation than dehydrogenation in the transformation between AP and 1PE. Due to the action of some enzyme(s) responsible for the formation of (R)-1PE from AP in the flowers, (R)-1PE is the dominant endogenous steroisomer of 1PE. The modification of 1PE into nonvolatile glycosidic forms is one of the reasons for why only a little 1PE is released from the flowers. The levels of AP, 1PE, and glycosides of 1PE increase during floral development, whereas the level of L-Phe decreases. These metabolites occur mostly in the anthers.

Herbivore-induced volatiles from tea (Camellia sinensis) plants and their involvement in intraplant communication and changes in endogenous nonvolatile metabolites.

As a defense response to attacks by herbivores such as the smaller tea tortrix ( Adoxophyes honmai Yasuda), tea ( Camellia sinensis ) leaves emit numerous volatiles such as (Z)-3-hexen-1-ol, linalool, α-farnesene, benzyl nitrile, indole, nerolidol, and ocimenes in higher concentration. Attack of Kanzawa spider mites ( Tetranychus kanzawai Kishida), another major pest insect of tea crops, induced the emission of α-farnesene and ocimenes from tea leaves. The exogenous application of jasmonic acid to tea leaves induced a volatile blend that was similar, although not identical, to that induced by the smaller tea tortrix. Most of these herbivore-induced plant volatiles (HIPV) were not stored in the tea leaves but emitted after the herbivore attack. Both the adaxial and abaxial epidermal layers of tea leaves emitted blends of similar composition. Furthermore, HIPV such as α-farnesene were emitted mostly from damaged but not from undamaged leaf regions. A principal component analysis of metabolites (m/z 70-1000) in undamaged tea leaves exposed or not to HIPV suggests that external signaling via HIPV may lead to more drastic changes in the metabolite spectrum of tea leaves than internal signaling via vascular connections, although total catechin contents were slightly but not significantly increased in the external signaling via HIPV.

Centrifugal precipitation chromatography, a powerful technique for the isolation of active enzymes from tea leaves (Camellia sinensis).

Centrifugal precipitation chromatography was developed approximately 10 years ago. In contrast to other counter-current chromatographic techniques, the centrifugal precipitation chromatography system is operated with two mutually miscible solutions separated by a cut-off membrane. Centrifugal precipitation chromatography was firstly introduced for the separation of proteins using an ammonium sulfate gradient. In this study we describe a novel approach using solvent-based protein precipitation for the isolation of active plant enzymes from tea leaves (Camellia sinensis) by centrifugal precipitation chromatography. We developed a gradient based on acetone and Tris-buffer, because the biological activity of carotenases in tea leaves cannot be preserved in the presence of ammonium sulfate. Parameters such as the critical solvent concentration, flow rate, buffer concentration, and sample load were determined and/or optimized. Subsequently, the newly developed separation protocol was successfully used for the isolation of active carotenoid cleavage enzymes from tea leaves. The isolated enzymes showed high enzymatic activities and purities and could be directly used for enzymatic assays and structure elucidation.