Polyphenol-Rich Beverage Consumption Affecting Parameters of the Lipid Metabolism in Healthy Subjects.

Polyphenols are a diverse and widely distributed class of secondary metabolites, which possess numerous beneficial properties including a modulation of glucose and lipid metabolism. This placebo-controlled human intervention study was performed to explore effects of polyphenol-rich beverage (PRB) uptake on lipid metabolism, as well as DNA integrity. In this case, 36 healthy men were randomly divided to consume either 750 mL of a PRB (containing 51% chokeberry, cranberry, and pomegranate) or a placebo drink daily for eight weeks. Only PRB consumption was found to decrease fat and protein intakes significantly compared to the preceding one-week washout period. During the intervention with PRB an increased fat-free mass was shown after four weeks, whereas a significant elevation in body weight and leptin was observed in placebo group. Blood lipids were not significantly altered after PRB consumption, while triglyceride levels increased after placebo drink intake. In platelets, a significant inhibition of phosphodiesterase (PDE) activity was observed, more pronounced in test group. Consuming the PRB decreased total DNA strand breaks in whole blood as well as H2O2-induced breaks in isolated lymphocytes. Overall, our study suggested beneficial effects on lipid metabolism by reduced energy intake, modulation of biomarkers such as PDE activity and improved DNA integrity associated with PRB consumption.

A Comparison between High-Performance Countercurrent Chromatography and Fast-Centrifugal Partition Chromatography for a One-Step Isolation of Flavonoids from Peanut Hulls Supported by a Conductor like Screening Model for Real Solvents.

Peanut hulls (Arachis hypogaea, Leguminosae), which are a side stream of global peanut processing, are rich in bioactive flavonoids such as luteolin, eriodictyol, and 5,7-dihydroxychromone. This study aimed to isolate these flavonoid derivatives by liquid-liquid chromatography with as few steps as possible. To this end, luteolin, eriodictyol and 5,7-dihydroxychromone were isolated from peanut hulls using two different techniques, high-performance countercurrent chromatography (HPCCC) and fast-centrifugal partition chromatography (FCPC). The suitability of the biphasic solvent system composed of n-hexane/ethyl acetate/methanol/water (1.0/1.0/1.0/1.5; v/v/v/v) was determined by the Conductor like Screening Model for Real Solvents (COSMO-RS), which allowed the partition ratio KD-values of the three main flavonoids to be calculated. After a one-step HPCCC separation of ~1000 mg of an ethanolic peanut hull extract, 15 mg of luteolin and 8 mg of eriodictyol were isolated with purities over 96%. Furthermore, 3 mg of 5,7-dihydroxychromone could be isolated after purification by semi-preparative reversed-phase liquid chromatography (semi-prep. HPLC) in purity of over 99%. The compounds were identified by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance spectroscopy (NMR).

Target-Guided Isolation of Progenitors of 1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) from Riesling Wine by High-Performance Countercurrent Chromatography.

High-performance countercurrent chromatography (HPCCC) was used for the target-guided isolation of precursors of 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) from Riesling wine. In separated HPCCC fractions of an Amberlite® XAD®-2 extract obtained from a German Riesling, TDN-generating fractions were identified by the acid-catalyzed hydrolysis of the progenitors at pH 3.0 and subsequent HS-GC-MS/MS analysis. The presence of multiple TDN-generating precursors in Riesling wine could be confirmed. From polar HPCCC fractions (11-13 and 14-16), 3,4-dihydroxy-7,8-dihydro-ß-ionone 3-O-rutinoside and 3,4-dihydroxy-7,8-dihydro-ß-ionone 3-O-ß-d-glucopyranoside were isolated as major TDN-precursors at a sufficient amount for structure elucidation by NMR spectroscopic studies. In the medium polar HPCCC factions (27-35), enzymatic hydrolysis liberated the aglycones 3-hydroxy-ß-ionone and 3-hydroxy-TDN in minor amounts. In further less polar TDN-generation fractions (36-44 and 45-50), glycosidic progenitors were absent; instead, a minor TDN formation most likely from non-conjugated constituents was observed.

Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography.

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar 'Yae-no-amacha' using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.

Shifts in biochemical and physiological responses by the inoculation of arbuscular mycorrhizal fungi in Triticum aestivum growing under drought conditions.

BACKGROUND: A decrease in rainfall is one of the main constraints on wheat production, although the association of wheat with arbuscular mycorrhizal fungi (AMF) may be an alternative for crop production under drought conditions. In the present study, we used three wheat cultivars (Purple, Ilustre and Maxi Baer) inoculated with two AMF strains, one obtained from the hyperarid Atacama Desert (northern Chile; Fm) and the other obtained from southern Chile (Cc). Plants were maintained under two irrigation conditions (normal irrigation and drought) and the physiological behaviour and enzymatic and nonenzymatic antioxidant activities in the shoots were determined. In addition, the phenolic compounds were identified by high-performance liquid chromatography-dioide array detection-electrospray ionization-tandem mass spectrometry and quantified. RESULTS: AMF colonization produced higher levels of efficiency of photosystem II and photosynthetic pigments. High values of catalase in Purple-Cc, ascorbate peroxidase in Purple-Cc, glutathione reductase in Maxi-Cc and superoxide dismutase in Purple-Cc, all under stress, were registered. Of the inoculated cultivars, Purple-Cc showed the highest flavonoid levels, whereas hydroxycinnamic acids were higher in Maxi-Fm without drought, with apigenin and luteolin being the most abundant. High levels of phenols were present in the Ilustre-Fm plants without drought. Under normal irrigation, high levels of antioxidant activity were registered in the AMF treatments, whereas, under stress conditions, in general, high values were observed under the Fm inoculation. CONCLUSION: Our results showed that the greatest antioxidant activity and phenolic content occurred in wheat plants inoculated with AMF, indicating their influence on coping with water stress, which is of importance in vast areas where global climate change is resulting in diminished rainfall. © 2021 Society of Chemical Industry.

Isolation of N-Ethyl-2-pyrrolidinone-Substituted Flavanols from White Tea Using Centrifugal Countercurrent Chromatography Off-Line ESI-MS Profiling and Semi-Preparative Liquid Chromatography.

N-Ethyl-2-pyrrolidinone-substituted flavanols (EPSF) are marker compounds for long-term stored white teas. However, due to their low contents and diasteromeric configuration, EPSF compounds are challenging to isolate. In this study, two representative epimeric EPSF compounds, 5'''R- and 5'''S-epigallocatechin gallate-8-C N-ethyl-2-pyrrolidinone (R-EGCG-cThea and S-EGCG-cThea), were isolated from white tea using centrifugal partition chromatography (CPC). Two different biphasic solvent systems composed of 1. N-hexane-ethyl acetate-methanol-water (1:5:1:5, v/v/v/v) and 2. N-hexane-ethyl acetate-acetonitrile-water (0.7:3.0:1.3:5.0, v/v/v/v) were used for independent pre-fractionation experiments; 500 mg in each separation of white tea ethyl acetate partition were fractionated. The suitability of the two solvent systems was pre-evaluated by electrospray mass-spectrometry (ESI-MS/MS) analysis for metabolite distribution and compared to the results of the CPC experimental data using specific metabolite partition ratio KD values, selectivity factors α, and resolution factors RS. After size-exclusion and semi-preparative reversed-phase liquid chromatography, 6.4 mg of R-EGCG-cThea and 2.9 mg of S-EGCG-cThea were recovered with purities over 95%. Further bioactivity evaluation showed that R- and S-EGCG-cThea possessed in vitro inhibition effects on α-glucosidase with IC50 of 70.3 and 161.7 µM, respectively.

In Vitro Inhibition of Phosphodiesterase 3B (PDE 3B) by Anthocyanin-Rich Fruit Juice Extracts and Selected Anthocyanins.

Phosphodiesterases (PDEs) are essential enzymes for the regulation of pathways mediated by cyclic adenosine monophosphate (cAMP). Secondary plant compounds like anthocyanins (ACs) can inhibit PDE activity and, consequently, may be beneficial for lipid metabolism. This study investigated 18 AC-rich juice extracts and pure reference compounds from red fruits for potential inhibitory effects on PDE 3B activity. Extracts were obtained through adsorption on Amberlite® XAD 7 resin. Based on this screening, the chokeberry, blueberry, pomegranate, and cranberry extracts were active, with half maximal inhibitory concentrations (IC50) ranging from 163 ± 3 µg/mL to 180 ± 3 µg/mL. The ACs in these extracts, peonidin-3-glucoside and cyanidin-3-arabinoside, were the most active single compounds (IC50 = 56 ± 20 µg/mL, 108 ± 6 µg/mL). All extracts comprised high amounts of phenolic compounds, as determined by the Folin-Ciocalteu assay, ranging from 39.8 ± 1.5 to 73.5 ± 4.8 g gallic acid equivalents (GAE)/100 g extract. Pomegranate and chokeberry extracts exhibited the largest amounts of polyphenols (72.3 ± 0.7 g GAE/100 g, 70.6 ± 4.1 g GAE/100 g, respectively). Overall, our results showed that fruit juice extracts and their ACs can inhibit PDE activity. Any potential health benefits in vivo will be investigated in the future.

Carbohydrate Hydrolase-Inhibitory Activity of Juice-Based Phenolic Extracts in Correlation to Their Anthocyanin/Copigment Profile.

Red fruits and their juices are rich sources of polyphenols, especially anthocyanins. Some studies have shown that such polyphenols can inhibit enzymes of the carbohydrate metabolism, such as α-amylase and α-glucosidase, that indirectly regulate blood sugar levels. The presented study examined the in vitro inhibitory activity against α-amylase and α-glucosidase of various phenolic extracts prepared from direct juices, concentrates, and purees of nine different berries which differ in their anthocyanin and copigment profile. Generally, the extracts with the highest phenolic content-aronia (67.7 ± 3.2 g GAE/100 g; cyanidin 3-galactoside; chlorogenic acid), pomegranate (65.7 ± 7.9 g GAE/100 g; cyanidin 3,5-diglucoside; punicalin), and red grape (59.6 ± 2.5 g GAE/100 g; malvidin 3-glucoside; quercetin 3-glucuronide)-showed also one of the highest inhibitory activities against α-amylase (326.9 ± 75.8 µg/mL; 789.7 ± 220.9 µg/mL; 646.1 ± 81.8 µg/mL) and α-glucosidase (115.6 ± 32.5 µg/mL; 127.8 ± 20.1 µg/mL; 160.6 ± 68.4 µg/mL) and, partially, were even more potent inhibitors than acarbose (441 ± 30 µg/mL; 1439 ± 85 µg/mL). Additionally, the investigation of single anthocyanins and glycosylated flavonoids demonstrated a structure- and size-dependent inhibitory activity. In the future in vivo studies are envisaged.

HILIC HPLC-ESI-MS/MS identification and quantification of the alkaloids from the genus Equisetum.

INTRODUCTION: The plant family Equisetaceae (Equisetopsida, Monilophyta; common name: horsetails) is part of an ancient group of spore producing plants. Today, Equisetum is the only surviving genus comprising 15 species in two subgenera (Equisetum and Hippochaete). Several unique alkaloids are described to occur in this genus, so far there is very little data on the occurrence and the amount of those alkaloids for the different species. OBJECTIVE: To establish an extraction method and an analytical method to detect and quantify the relevant Equisetum-type alkaloids and to create a quantitative data set on the alkaloid content of all Equisetum species worldwide. METHODOLOGY: Hydrophilic interaction liquid chromatography high-performance liquid chromatography tandem mass spectrometry (HILIC HPLC-MS/MS) in electrospray ionisation (ESI) positive mode was used to analyse and quantify the alkaloid content of 68 Equisetum samples. RESULTS: The presence of nicotine in at least one sample of each Equisetum species could be demonstrated. The total nicotine amount rarely exceeded 250 µg/kg and 50 µg/kg for the subgenus Equisetum and Hippochaete, respectively. Besides nicotine, Equisetum-type alkaloids (mainly palustrine and palustridiene) were only detected in three species, namely E. palustre, E. bogotense and E. giganteum. For E. giganteum, palustridiene was detected at levels around the limit od detection (LoD) (25 µg/kg), whereas in E. palustre and E. bogotense, both alkaloids (palustrine and palustridiene) were detected at much higher levels (20-800 mg/kg). CONCLUSIONS: All Equisetum species occurring worldwide were successfully subjected to a detailed qualitative and quantitative alkaloid analysis using a newly developed HILIC-HPLC-ESIpos-MS/MS approach. The data set can be used to distinguish different Equisetum-chemotypes.

Effect of fertilization and arbuscular mycorrhizal fungal inoculation on antioxidant profiles and activities in Fragaria ananassa fruit.

BACKGROUND: The main methods used to increase the yield and quality of strawberry fruit produced in acidic soils with low P availability include root colonization by arbuscular mycorrhizal (AM) fungi and adjusting the type of P supplementation by means of traditional (TF) or organic (OF) fertilization, and adjusting nutrient doses. In this study, the antioxidant properties of strawberry fruit were evaluated under different treatments of fertilization (TF or OF) and different doses of P supplied at planting (0, 50 or 100% of the agronomic recommendation) and in the presence or absence of AM fungus as a bioinoculant. RESULTS: Fruits without fertilization treatments and with TF presented with higher anthocyanin concentrations. In general, higher values were obtained without AM colonization. However, spectrophotometric tests showed the highest activity and concentration in the AM-inoculated treatments. It is likely that phenolic compounds other than anthocyanins are present in the extracts. These other compounds could not be identified by the method used but could be detected by the Folin-Ciocalteu method. CONCLUSION: This study provides information that allows for improvements in strawberry fruit quality by agronomic management, with a potential beneficial effect on the health of consumers. © 2018 Society of Chemical Industry.

Evaluation of Grenache, Graciano and Tempranillo grape stilbene content after field applications of elicitors and nitrogen compounds.

BACKGROUND: Stilbenes have a significant biological activity and are one of the most important non-flavonoid contributors to grape and wine health-related properties. The accumulation of this class of compounds could be favored by viticultural practices such as the application of biostimulants. However, stilbene concentration also depends on several factors, including, for example, grape variety. Therefore, the aim of this work was to study the influence of foliar treatments carried out with elicitors (methyl jasmonate (MeJ) and a commercial foliar spray (YD)) and nitrogen compounds (phenylalanine and urea) on the grape stilbene composition of three varieties: Grenache, Graciano and Tempranillo. An ultra-high-pressure liquid chromatographic methodology was validated for stilbene determination. RESULTS: Results showed that, despite the huge influence of the grape variety, YD significantly improved stilbene composition in Grenache and Graciano, while MeJ increased the stilbene content in Graciano and Tempranillo. As for the nitrogen treatments, phenylalanine significantly increased the stilbene concentration in Graciano, while urea treatment increased it in Tempranillo. However, the application of elicitors had a greater effect than the nitrogen compounds. CONCLUSION: Overall, the foliar application of the elicitors could be a suitable practice for increasing the amount of stilbenes in grape and, therefore, its nutraceutical properties. © 2017 Society of Chemical Industry.

Incidence of Pyrrolizidine Alkaloids in Herbal Medicines from German Retail Markets: Risk Assessments and Implications to Consumers.

The occurrence of potentially toxic pyrrolizidine alkaloids (PAs) in herbal medicines (HMs) is currently intensely being discussed in Europe. Pyrrolizidine alkaloids, particularly the 1,2-unsaturated PAs, are undesired compounds in HMs due to their potential hepatotoxic and carcinogenic properties. In this study, 98 widely patronized HMs from six popular German retail supermarkets/drugstores, as well as from pharmacies, were analyzed by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry for the presence of PAs. The results showed that about 63% of the HMs were PA positive, whereas the average PA concentration of the samples was 201 µg/kg, the highest concentration of PAs (3270 µg/kg) was attributed to a product that was purchased from the pharmacy and contained Hypericum perforatum L. (St. John's Wort) as an active ingredient. In addition, H. perforatum-containing products were frequently contaminated with PAs from Echium spp., while both Cynara cardunculus L. products and fixed-combination products of Gentiana lutea L., Rumex acetosa L., Verbena officinalis L., Sambucus nigra L., and Primula veris L. products were commonly contaminated with PAs of Senecio spp. The study showed that H. perforatum, C. cardunculus, Urtica dioica L., and fixed-combination products were frequently contaminated with PA levels above the recommended values of both the German and European Medicines Agencies. Copyright © 2017 John Wiley & Sons, Ltd.

Survey of pyrrolizidine alkaloids in seven varieties of Lappula squarrosa: An alternative source of heart-healthy vegetable oil.

INTRODUCTION: Growing demand for heart-healthy omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is putting stress on wild fish stocks. There is now a compelling need for new and novel sources of non-traditional seed oils containing high stearidonic acid (SDA), a precursor of EPA and DHA, to reduce this demand. The seed oil of Lappula squarrosa is one of the richest sources of SDA, however, the plant has been found to contain toxic pyrrolizidine alkaloids (PAs). OBJECTIVE: In this study, the PA concentrations of seven varieties (A-G) of Lappula squarrosa were analysed to determine the most suitable varieties for commercial seed oil production. METHODS: Whilst the clean-up procedure for the PAs in the roots, flowers and leaves was on diatomaceous earth columns and finally analysed with GC-EI-MS, that of the seeds was through SCX-SPE and a more sensitive HPLC-ESI-MS/MS sum parameter method was used in the analysis. RESULTS: Altogether six PAs (supinine, amabiline, intermedine, lycopsamine and 3'-acetylintermedine) including one unknown retronecine-type PA were identified with variety C recording the lowest total PA concentration (4.64 mg seneciphylline equivalents (SE)/g dry weight (d.w.)). Besides, the total PA concentrations in the seeds of Lappula squarrosa varieties ranged between 2.88 µg PA/g and 10.36 µg PA/g d.w. CONCLUSION: Based solely on overall PA concentrations and PA distribution, variety D (5.95 mg SE/g d.w.) was found to be a potential candidate for commercial seed oil cultivation.

Flavonoids from the flowers of Impatiens glandulifera Royle isolated by high performance countercurrent chromatography.

INTRODUCTION: Impatiens glandulifera Royle (Balsaminaceae) is an annual herb from the Himalaya region, currently widespread along European river systems and one of the most important neophyte invading plants in Germany. Exploring the effects of allelopathic plant chemicals is important for the understanding of its ecological impacts in the process of suppression of indigenous plant species. OBJECTIVE: To investigate the chemical composition of Impatiens glandulifera flowers (IGFs) using high performance countercurrent chromatography (HPCCC). METHODS: The flowers of Impatiens glandulifera were manually separated and extracted with ethanol. LC-ESI-MS/MS was used to characterise the crude extract of IGF. The various flavonoids detected were isolated by HPCCC using of methyl tert-butyl ether-acetonitrile-water (2:2:3, v/v/v). The combination of the data provided by preparative ESI-MS/MS metabolite profiling, LC-ESI-MS/MS, UV-vis and 1D/2D-NMR spectroscopic analysis was used to elucidate the structures of the isolated compounds. RESULTS: HPCCC runs led to the direct isolation of pure dihydromyricetin (ampelopsin), eriodictyol-7-O-glucoside, kaempferol-3-O-glucoside (astragalin) and kaempferol-3-O-6"-malonyl-glucoside, as well as the pre-purification of kaempferol-3-O-rhamno-rhamnosyldiglucoside, quercetin-3-O-galactoside (hyperoside), quercetin and kaempferol in a single step. CONCLUSION: This is the first report on the flavonoid composition of the species Impatiens glandulifera. The developed protocol was successfully used to isolate the main flavonoids from the crude extract of IGFs. This combined HPCCC and HPLC procedure could be applied to the fast fractionation and recovery of flavonoid derivatives of other plant extracts.

Isolation of cytotoxic diterpenoids from the Chilean medicinal plant Azorella compacta Phil from the Atacama Desert by high-speed counter-current chromatography.

BACKGROUND: Azorella compacta (Apiaceae) is a native Chilean cushion shrub which produces a resin containing mulinane and azorellane diterpenoids. This plant has been used since pre-Colombian times to treat inflammation and dental neuralgias. In this work the first preparative fractionation of diterpenoids present in this plant by means of high-speed counter-current chromatography (HSCCC) was applied, and cytotoxic effects of the isolated compounds were evaluated for the first time against a panel of MCF7 cells. RESULTS: The major compounds isolated were identified by means of spectroscopy as azorellanol, 13α, 14α-dihydroxymulin-11-en-20-oic acid, mulinolic acid, mulin-11,13-dien-20-oic acid, 17-acetoxy-mulin-11,13-dien-20 oic acid, and 17-acetoxy-mulinic acid (compounds 7, 9-11 and 13, respectively), and four minor diterpenoids [7-deacetyl-azorellanol (6), 13-epi-azorellanol, 7-acetoxy-mulin-9,12-diene, and 17-acetoxy-mulin-11,13-dien-20-oic acid (compounds 4, 8 and 12)], together with three new minor diterpenoids: 13ß,14ß-dihydroxymulin-11-en-20-oic acid (1), 13-epiazorellanone (2) and 13-epi-7-deacetyl-azorellanol (3) were identified. Besides, compounds 4, 6, 7, 8 and 11 displayed good cytotoxic activity (less than 50% cell viability at 100 µM). Among them, compound 7, an acetylated azorellane, was the most active. CONCLUSIONS: HSCCC allowed the isolation of 13 diterpenoids present in A. compacta. Three compounds are reported for the first time. Isolated azorellanes are more potent cytotoxic agents than are mulinanes. © 2015 Society of Chemical Industry.

Antiprotozoal activity of Buxus sempervirens and activity-guided isolation of O-tigloylcyclovirobuxeine-B as the main constituent active against Plasmodium falciparum.

Buxus sempervirens L. (European Box, Buxaceae) has been used in ethnomedicine to treat malaria. In the course of our screening of plant extracts for antiprotozoal activity, a CH2Cl2 extract from leaves of B. sempervirens showed selective in vitro activity against Plasmodium falciparum (IC50 = 2.79 vs. 20.2 µg/mL for cytotoxicity against L6 rat cells). Separation of the extract by acid/base extraction into a basic and a neutral non-polar fraction led to a much more active and even more selective fraction with alkaloids while the fraction of non-polar neutral constituents was markedly less active than the crude extract. Thus, the activity of the crude extract could clearly be attributed to alkaloid constituents. Identification of the main triterpene-alkaloids and characterization of the complex pattern of this alkaloid fraction was performed by UHPLC/+ESI-QTOF-MS analyses. ESI-MS/MS target-guided larger scale preparative separation of the alkaloid fraction was performed by 'spiral coil-countercurrent chromatography'. From the most active subfraction, the cycloartane alkaloid O-tigloylcyclovirobuxeine-B was isolated and evaluated for antiplasmodial activity which yielded an IC50 of 0.455 µg/mL (cytotoxicity against L6 rat cells: IC50 = 9.38 µg/mL). O-tigloylcyclovirobuxeine-B is thus most significantly responsible for the high potency of the crude extract.

Sustainable In Silico-Supported Ultrasonic-Assisted Extraction of Oligomeric Stilbenoids from Grapevine Roots Using Natural Deep Eutectic Solvents (NADES) and Stability Study of Potential Ready-to-Use Extracts.

Grapevine roots, as a side-stream of a vineyard, are a sustainable resource for the recovery of oligomeric stilbenoids, such as the bioactive r-viniferin. The aim of this study is to evaluate an in silico-supported method, based on the Conductor-like Screening Model for Real Solvents (COSMO-RS), for selection of environmentally friendly natural deep eutectic solvents (NADES) with regard to the extraction of grapevine roots. The most suitable NADES system for ultrasonic-assisted extraction of r-viniferin was choline chloride/1,2-propanediol. The optimal extraction parameters for r-viniferin were determined using single-factor experiments as follows: choline chloride/1,2-propanediol 1/2 mol/mol, 10 wt% H2O, biomass/NADES ratio 1/10 g/g, and 10 min extraction time. Under optimized conditions, the extraction yield of r-viniferin from grapevine roots reached 76% of the total r-viniferin content. Regarding stability, stilbenoids in choline chloride/1,2-propanediol remained stable during 128 days of storage at ambient temperature. However, fructose/lactic acid-based NADES were observed to degrade stilbenoids; therefore, the removal of the NADES will be of interest, with a suitable method implemented using Amberlite® XAD-16N resin. As green solvents, the NADES have been used as effective and environmentally friendly extractants of stilbenoid-containing extracts from grapevine roots for potential applications in the cosmetic and pharmaceutical industry or as nutraceuticals in the food industry.

Stearidonic acid improves eicosapentaenoic acid status: studies in humans and cultured hepatocytes.

Background: Ahiflower oil from the seeds of Buglossoides arvensis is rich in α-linolenic acid (ALA) and stearidonic acid (SDA). ALA and SDA are potential precursor fatty acids for the endogenous synthesis of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are n3-long chain polyunsaturated fatty acids (n3-LC-PUFAS), in humans. Since taurine, an amino sulfonic acid, is often associated with tissues rich in n3-LC-PUFAS (e.g., in fatty fish, human retina), taurine may play a role in EPA- and DHA-metabolism. Objective: To examine the capacity of the plant-derived precursor fatty acids (ALA and SDA) and of the potential fatty acid metabolism modulator taurine to increase n3-LC-PUFAS and their respective oxylipins in human plasma and cultivated hepatocytes (HepG2 cells). Methods: In a monocentric, randomized crossover study 29 healthy male volunteers received three sequential interventions, namely ahiflower oil (9 g/day), taurine (1.5 g/day) and ahiflower oil (9 g/day) + taurine (1.5 g/day) for 20 days. In addition, cultivated HepG2 cells were treated with isolated fatty acids ALA, SDA, EPA, DHA as well as taurine alone or together with SDA. Results: Oral ahiflower oil intake significantly improved plasma EPA levels (0.2 vs. 0.6% of total fatty acid methyl esters (FAMES)) in humans, whereas DHA levels were unaffected by treatments. EPA-levels in SDA-treated HepG2 cells were 65% higher (5.1 vs. 3.0% of total FAMES) than those in ALA-treated cells. Taurine did not affect fatty acid profiles in human plasma in vivo or in HepG2 cells in vitro. SDA-rich ahiflower oil and isolated SDA led to an increase in EPA-derived oxylipins in humans and in HepG2 cells, respectively. Conclusion: The consumption of ahiflower oil improves the circulating levels of EPA and EPA-derived oxylipins in humans. In cultivated hepatocytes, EPA and EPA-derived oxylipins are more effectively increased by SDA than ALA.

In Silico-Assisted Isolation of trans-Resveratrol and trans-ε-Viniferin from Grapevine Canes and Their Sustainable Extraction Using Natural Deep Eutectic Solvents (NADES).

Grapevine canes are an important source of bioactive compounds, such as stilbenoids. This study aimed to evaluate an in silico method, based on the Conductor-like Screening Model for Real Solvents (COSMO-RS) to isolate stilbenoids from a grapevine cane extract by offline heart-cut high-performance countercurrent chromatography (HPCCC). For the following extraction of resveratrol and ε-viniferin from grapevine canes, natural deep eutectic solvents (NADES) were used as an environmentally friendly alternative to the traditionally used organic solvents. In order to evaluate a variety of combinations of hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs) for the targeted extraction of stilbenoids, COSMO-RS was applied. In particular, ultrasonic-assisted extraction using a solvent mixture of choline chloride/1,2-propanediol leads to higher extraction yields of resveratrol and ε-viniferin. COSMO-RS calculations for NADES extraction combined with HPCCC biphasic solvent system calculations are a powerful combination for the sustainable extraction, recovery, and isolation of natural products. This in silico-supported workflow enables the reduction of preliminary experimental tests required for the extraction and isolation of natural compounds.

Methylation of catechins and procyanidins by rat and human catechol-O-methyltransferase: metabolite profiling and molecular modeling studies.

Catechins and procyanidins are major polyphenols in plant-derived foods. Despite intensive studies in recent years, neither their biochemical nor their toxicological properties have been clarified sufficiently. This study aimed to compare the methylation of catechins and procyanidins by the enzyme catechol-O-methyltransferase (COMT) in vitro. We conducted incubations with rat liver cytosol and human placental cytosol including S-adenosyl-l-methionine. The set of substrates comprised the catechins (-)-epicatechin (EC) and (+)-catechin (CAT), the procyanidin dimers B1, B2, B3, B4, B5, and B7 as well as procyanidin trimer C1. After extraction, metabolites were analyzed by means of liquid chromatography-electrospray ionization-mass spectrometry and liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry. EC and CAT were converted to two monomethylated metabolites each by human and rat COMT, with the 3'-O-methyl derivatives being consistently the main metabolites. Furthermore, the flavanyl units of procyanidins were methylated consecutively, leading to monomethylated and dimethylated dimeric metabolites as well as monomethylated, dimethylated, and trimethylated C1 metabolites. The methylation status of each flavanyl unit was determined by means of mass spectrometric quinone-methide fragmentation patterns. In addition, molecular modeling studies were performed with the aim to predict the preferred site of methylation and to verify the experimental data. In conclusion, our results indicate that the degree and position of methylation depend clearly on the three-dimensional structure of the entire substrate molecule.