Concentrations Of Total Flavonols Research Articles

Color, Antioxidant Capacity and Flavonoid Composition in Hibiscus rosa-sinensis Cultivars

Hibiscus rosa-sinensis plants are mainly cultivated as ornamental plants, but they also have food and medicinal uses. In this work, 16 H. rosa-sinensis cultivars were studied to measure their colorimetric parameters and the chemical composition of hydroethanolic extracts obtained from their petals. These extracts were characterized using UHPLC-ESI+-Obitrap-MS, and their antioxidant activity was evaluated using the ORAC assay. The identified flavonoids included anthocyanins derived from cyanidin, glycosylated flavonols derived from quercetin and kaempferol, and flavan-3-ols such as catechin and epicatechin. Cyanidin-sophoroside was the anthocyanin present in extracts of lilac, pink, orange, and red flowers, but was not detected in extracts of white or yellow flowers. The total flavonol concentration in the flower extracts was inversely proportional to the total anthocyanin content. The flavonol concentration varied according to the cultivar in the following order: red < pink < orange < yellow ≈ white, with the extract from the red flower presenting the lowest flavonol concentration and the highest anthocyanin concentration. The antioxidant activity increased in proportion to the anthocyanin concentration, from 1580 µmol Trolox®/g sample (white cultivar) to 3840 µmol Trolox®/g sample (red cultivar).

Comprehensive anthocyanin and flavonol profiling and fruit surface color of 20 blueberry genotypes during postharvest storage

Blueberry surface color is determined in large part by anthocyanin pigments and is one of the most important quality traits influencing consumer preference. Postharvest changes in fruit surface color and phenolic compounds, including anthocyanins, have been reported in blueberries; however, the relationships between these changes had not yet been investigated. A total of 25 anthocyanins and 14 flavonols were quantified across 20 blueberry genotypes at harvest and during four weeks of postharvest storage in 2019 and 2020. Total anthocyanin concentration ranged from 585.4 to 2556.4 mg kg‐1 across genotypes and was higher than total flavonol concentration that ranged from 129.3 to 331.0 mg kg‐1. Malvidin glycosides were the major anthocyanins in all genotypes; however, distinct anthocyanin profiles were observed among genotypes based on differences in the type of glycosylation. Quercetin 3-O-galactoside was the most abundant flavonol in all genotypes. Changes in total anthocyanin and total flavonol concentrations showed various trends during storage, depending on the genotype and the season. In contrast, anthocyanin and flavonol profiles for each genotype remained constant during storage and between seasons. Surface color parameters (lightness, chroma, and hue angle) showed weak correlations (r < 0.4) with anthocyanin concentrations measured at harvest and during postharvest storage. However, the color changes (Δ color) over four weeks of storage showed a strong correlation (r > 0.7) with changes in anthocyanin concentrations. This study provides novel understanding of the relationship between changes in anthocyanins and fruit surface color during postharvest storage in blueberries.

Adapting wine grape production to climate change through canopy architecture manipulation and irrigation in warm climates.

Grape growing regions are facing constant warming of the growing season temperature as well as limitations on ground water pumping used for irrigating to overcome water deficits. Trellis systems are utilized to optimize grapevine production, physiology, and berry chemistry. This study aimed to compare 6 trellis systems with 3 levels of applied water amounts based on different replacements of crop evapotranspiration (ETc) in two consecutive seasons. The treatments included a vertical shoot position (VSP), two modified VSPs (VSP60 and VSP80), a single high wire (SH), a high quadrilateral (HQ), and a Guyot pruned VSP (GY) combined with 25%, 50%, and 100% ETc water replacement. The SH had greater yields, whereas HQ was slower to reach full production potential. At harvest in both years, the accumulation of anthocyanin derivatives was enhanced in SH, whereas VSPs decreased them. As crown porosity increased (mostly VSPs), berry flavonol concentration and likewise molar % of quercetin in berries increased. Conversely, as leaf area increased, total flavonol concentration and molar % of quercetin decreased, indicating a preferential arrangement of leaf area along the canopy for overexposure of grape berry with VSP types. The irrigation treatments revealed linear trends for components of yield, where greater applied water resulted in larger berry size and likewise greater yield. 25% ETc was able to increase berry anthocyanin and flavonol concentrations. Overall, this study evidenced the efficiency of trellis systems for optimizing production and berry composition in Californian climate, also, the feasibility of using flavonols as the indicator of canopy architecture.

In Vitro Antioxidant Activities of Methanol Extracts of Three Achillea Species from Turkey

In this study, total phenolics and flavonoid compounds of methanol extract concentrations of three medicinal plant, Asteraceae (Compositae) L. genus that are grown in Turkey and belong to the genus Achillea, were determined with the goal of measuring their antioxidant activities. Antioxidant capacity was measured by widely used iron reducing power, DPPH radical scavenging activity and metal chelating capacity. The antioxidant activities of the achillea extracts used in the study were compared with the standard antioxidants (BHA, BHT and α-tocopherol), which were frequently used as antioxidant food additives. According to the free radical scavenging activity antioxidant results, all the extracts exhibited higher DPPH radical scavenging activity than the standards used. The extract from A.boissieri showed remarkable 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (68.51% at 37.5 μg/mL) comparable with synthetic antioxidants. The ferric reducing antioxidant power was found to be moderate in methanolic extract of Achillea species, whereas the chelating capacity of the extracts were found to be lower as compared to the standards. In addition, total phenolic, flavonoid and flavonol content of all extracts were measured spectrophotometrically and the results were expressed as "gallic acid equivalent" or "quercetin equivalent". The total phenolic content was expressed as equivalents of gallic acid and the results were observed to range from 11.86 to 23.63 mg/g dry extract weight. The total flavonoid concentrations of Achillea extracts were expressed as quercetin equivalent. Flavonoid content ranged from 15.05 to 29.70 mg/g. Total flavonol concentrations of the extracts were determined to be between 5.92 and 7.20 mg/g in terms of quercetin equivalent. This study showed that Achillea L. species, which has been used for treatment in Anatolia for years, can be used as a potential natural antioxidant source.

Influence of cluster positions in the canopy and row orientation on the flavonoid and volatile compound profiles in Vitis vinifera L. Cabernet franc and Chardonnay berries

Sunlight conditions around grape clusters vary with their positions, and can have a significant effect on grape berry compounds. This study investigated the influence of cluster positions in the canopy (interior and two exterior canopy sides) and vineyard row orientation (north–south and east–west) on flavonoid and volatile compound profiles of Vitis vinifera L. cvs ‘Cabernet franc’ (CF) and ‘Chardonnay’ (CH) berries in two consecutive years. The experimental vineyard was located in Jiaodong Peninsula of China, which is characterized by a temperate monsoon-type climate and relatively short sunlight duration. Clusters located in the interior of the canopy received less sunlight irradiation than the exterior positions, and the average temperature around clusters located in different positions differed slightly. The results showed that over two years, the positions of clusters in the canopy had no consistent impact on cluster weight, berry weight, juice total soluble solids or titratable acidity for either cultivar. For both cultivars, the interior clusters had lower total flavonol concentrations than the exterior clusters, while the position of clusters in the canopy had no major impacts on the composition of anthocyanins and flavan-3-ols. The volatile compounds were somewhat influenced by the positions of clusters in the canopy, while some bound norisoprenoids and terpenoids had lower levels in interior clusters than in exterior clusters. These results will help winegrowers make decisions regarding harvest strategies.

Responses of Lotus corniculatus to environmental change 3: The sensitivity of phenolic accumulation to growth temperature and light intensity and effects on tissue digestibility

Growth temperature and light intensity are major drivers of phenolic accumulation in Lotus corniculatus resulting in major changes in carbon partitioning which significantly affects tissue digestibility and forage quality. The response of plant growth, phenolic accumulation and tissue digestibility to light and temperature was determined in clonal plants of three genotypes of Lotus corniculatus (birdsfoot trefoil) cv Leo, with low, intermediate or high levels of proanthocyanidins (condensed tannins). Plants were grown from 10 °C to 30 °C, or at light intensities from 20 to 500 µm m-2 s-1. Plants grown at 25 °C had the highest growth rate and highest digestibility, whereas the maximum tannin concentration was found in plants grown at 15 °C. Approximately linear increases in leaf flavonol glycoside levels were found with increasing growth temperature in the low tannin genotype. Tannin hydroxylation increased with increasing growth temperature but decreased with increasing light intensity. The major leaf flavonols were kaempferol glycosides of which kaempferol-3-glucoside and kaempferol-3,7-dirhamnoside were the major components. Increases in both tannin and total flavonol concentrations in leaves were linearly related to light intensity and were preceded by a specific increase in the transcript level of a non-legume type chalcone isomerase. Changes in growth temperature and light intensity, therefore, result in major changes in the partitioning of carbon into phenolics, which significantly affects tissue digestibility and nutritional quality with a high correlation between tannin concentration and leaf digestibility.

Influence of Profiles and Concentrations of Phenolic Compounds in the Coloration and Antioxidant Properties of Gaultheria poeppigii Fruits from Southern Chile.

Chaura (Gaultheria poeppigii) is a plant species native from Southern Chile, which produces a berry fruit with potential beneficial health effects due to its content of phenolic compounds. The qualitative and quantitative determination of the phenolic compounds from fruits of different colored genotypes (white-, pink- and red-colored) collected from the Osorno volcano and the Conguillío National Park (CNP) in southern Chile were analyzed by mass spectrometry (HPLC-DAD-ESI-MS/MS) and HPLC-DAD, respectively. The total content of phenolic compounds was evaluated by the Folin-Ciocalteu method, and its antioxidant activity by the CUPRAC, TEAC and DPPH methods. Four anthocyanins were detected, with glycosylated derivatives of delphinidin and cyanidin being the most abundant. Fruits with more coloration had higher anthocyanin concentrations. Six flavonols were detected, with quercetin derivatives being the most abundant. The highest concentration of total flavonols reached 0.41mgg-1 in red colored fruits. The profiles of phenolic compounds showed differences between fruits depending on both the color and the area of collection. Finally, it would be interesting to evaluate the genetic profiles of chaura to determine whether this variation in phenolics and colorations is dependent on the geographical location or dependent on the genotype of the plant.

Correlations between urinary concentrations and dietary intakes of flavonols in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

In this study, we aimed to study the correlation between acute and habitual intakes of flavonols, their main food sources and their 24-h urinary concentrations in an European population. A 24-h dietary recall (24-HDR) and 24-h urine samples were collected on the same day from a convenience subsample of 475 men and women from four countries (France, Italy, Greece and Germany) of the European Prospective Investigation into Cancer and Nutrition (EPIC) study. A standardized 24-HDR software and a country/centre-specific validated dietary questionnaire (DQ) were used to collect acute and habitual dietary data, respectively. The intake of dietary flavonols was estimated using the Phenol-Explorer database. Urinary flavonols (quercetin, isorhamnetin, and kaempferol) were analysed using tandem mass spectrometry with a previous enzymatic hydrolysis. Weak partial Spearman correlations between both dietary acute and habitual intake and urinary concentrations of quercetin (both Rpartial ~ 0.3) and total flavonols (both Rpartial ~ 0.2) were observed. No significant correlations were found for kaempferol and isorhamentin. Regarding flavonol-rich foods, weak correlations were found between urinary concentrations of quercetin and total flavonols and the acute intake of onions and garlics, fruits, tea, and herbal tea (all Rpartial ~ 0.2). For habitual intake, statistically significant correlations were only found between urinary quercetin concentration and herbal tea (Rpartial = 0.345) and between urinary total flavonol concentration and tea, and herbal tea consumption (Rpartial ~ 0.2). Our results suggest that urinary quercetin level can be used as potential concentration biomarkers of both acute and habitual quercetin intake, while urinary concentrations of flavonols are unlikely to be useful biomarkers of individual flavonol-rich foods.

Determination of Flavonoids and Carotenoids and Their Contributions to Various Colors of Rose Cultivars (Rosa spp.).

Rose is one of the most valuable ornamental crops worldwide. In this study, the composition of hydrophilic and lipophilic pigments in petals of six rose cultivars at seven developing stages was investigated using high performance liquid chromatography and mass spectrometry. Four anthocyanins, 20 flavonols, and 10 carotenoids were detected in petals of tested cultivars. Major individual anthocyanin, flavonol, and carotenoid were cyanidin/pelargonidin 3,5-diglucoside, kaempferol 3-O-rhamnoside, and (9Z)-violaxanthin, respectively. Significant differences were observed in pigments content in petals of different rose cultivars. The yellow petals of YI and GC exhibited no to very small amounts of anthocyanins, moderate amount of total flavonols, and highest content of total carotenoids. Similarly, pink petals of PF, WQ, and YX showed average concentration of total anthocyanins, highest concentration of total flavonols, and small amount of carotenoids. Further, orange petals of CH showed highest content of total anthocyanins, lowest content of total flavonols, and average content of total carotenoids. Correlation analysis demonstrated that there were many pigments influencing petal colors. Moreover, multiple linear regression indicated that pelargonidin 3,5-diglucoside, total anthocyanins and (9Z)-violaxanthin were the major factors. In addition, this study showed that orange cultivar CH, pink cultivar PF and yellow cultivar YI can have great potential as a natural source for the extraction of pelargonidin 3-O-glucoside, kaempferol 3-O-rhamnoside, and (9Z)-violaxanthin, respectively. These investigations would contribute toward understanding the mechanism on the development of flower colors and provide a theoretical basis for the breeding of rose with specific color.

FTIR PHYTOCHEMICAL FINGERPRINTING AND ANTIOXIDANT ANLYSES OF SELECTED INDOOR NON-FLOWERING INDOOR PLANTS AND THEIR INDUSTRIAL IMPORTANCE

Objective: phytochemical screening and antioxidant activity analyses of selected indoor plants and to evaluate commercial applications.Methods: Qualitative and quantitative phytochemical analyses of alcoholic and aquatic crude extracts of leaves of selected non-flowering indoor plants were assessed using standard protocols and later compared with FTIR analyses. Antioxidant and antibacterial activities of the extracts were studiedResults: Phytochemical analysis of polar solvent extractions of the four selected plants Pedilanthus tithymaloides, Cordyline terminalis, Tradescantia zebrine and Rhoeo discolou. Indicated the presence of tannins in all four varieties terpenoids in 3, flavonols, phytosterols and phenols in two plants, followed by alkaloids. The phytochemical analyses were supported by FTIR reports. Quantitative studies indicated variations in flavonol, tannin and phenols concentrations among the four species. High concentrations of Total flavonols (P. tithymaloides) and Tannins (C. terminalis) were observed. C. terminalis extract showed comparatively highest reducing power followed by R. discolour and P. tithymaloides extracts. Antibiotic Sensitivity Testing indicated P. tithymaloides showed a maximum zone of inhibition compared to R. discolor. C. terminalis plant leaf extract showed a faint zone of inhibition against E. fecalis while others couldnot. Intense colors of C. terminalis and T. zebrine plants could be used as a natural dye as well as pH indicator. Conclusion: The rich concentrations of the tannins from non-flowering indoor plants could be the future option of dyes and dyeing industry as natural colorants as well as pH indicators. These plants were rich sources of phytochemicals (phenols, flavonols, tannins, and phytosterols), with antioxidant and antibacterial activity.

Nested effects of berry half, berry and bunch microclimate on biochemical composition in grape

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Aim&lt;/strong&gt;: Polyphenol composition, an important component of grape quality, is strongly influenced by fruit microclimate. However, information relies exclusively on whole berry data and the underlying response functions to microenvironment variables remain essentially unknown. The aim of this study was therefore to analyze the biochemical composition of grapes at both bunch and berry scales, in relation with microclimate.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Methods and results&lt;/strong&gt;: Whole berries and berry halves were sampled in mature defoliated bunches from two neighboring Bordeaux vineyards with contrasting row orientations (&lt;em&gt;Vitis vinifera&lt;/em&gt; cv. Merlot). Flavonoid and amino-acid contents were analyzed by HPLC methods. The main sources of variation were bunch azimuth, berry exposure and, only in South-exposed bunches, berry side. Models were used to estimate radiation at the berry surface and temperature. Intense effects of bunch side and berry side on total flavonol and anthocyanin concentrations were observed. These results were all consistent at both bunch and berry scales. However, the most intense effects were observed at berry scale and mitigated by scaling up from berry to bunch.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;: Total flavonol concentrations in the berry skin exhibited a clear positive linear relationship with solar radiation. The large heterogeneity of composition at berry scale is consistent with the better known heterogeneity at bunch scale.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Significance and impact of the study&lt;/strong&gt;: Models and original response functions to microclimate could help optimize vineyard management and grape ripening.&lt;/p&gt;

Isoflavone Content in Subterranean Clover Germplasm from Sardinia.

Subterranean clover (Trifoliumsubterraneum) is an important pasture legume, and Sardinia is known as a major centre of diversification of this species. As other legumes, this clover produces biologically active flavonoids including the subclass of isoflavones that are natural phytoestrogens with positive health effects. Present sources of isoflavones for medical/nutraceutical treatments are red clover (Trifoliumpratense) and soybean (Glycinemax). This study assessed the content and composition of flavonoids in 14 subterranean clover genotypes from Sardinia, grown ex-situ in comparison with two red clover ecotypes, to acquire information on the potential of the species as an alternative source of isoflavones for possible exploitation. Twenty compounds were tentatively identified across the two clovers after HPLC and LC/ESI-MS analyses, including clovamide, four flavonols, and 15 isoflavones. Most compounds were present as glucosides or glucosyl malonates. Subterranean clover extracts mainly comprised of derivatives of the isoflavones genistein, biochanin A, and formononetin. Compared to red clover, subterranean clover had higher content of total isoflavones and lower concentration of total flavonols. The isoflavone concentration in subterranean clover was higher than literature data for soybean or red clover. The existing genotypic variation warrants the possibility of selecting varieties with high isoflavone concentration for nutraceutical or pharmaceutical purposes.

Bioavailability of quercetin in humans and the influence of food matrix comparing quercetin capsules and different apple sources

The objective of the four-way cross-over pilot study was the investigation of quercetin bioavailability after ingestion of apple quercetin incorporated in different matrices and quercetin dihydrate capsule. Six healthy volunteers were given a standard diet supplemented with 71μmol quercetin equivalents from vacuum impregnated apple chips, apple peel extract capsules and apple peel. Quercetin dihydrate capsules were used as control. The vacuum impregnated apple chips were enriched with a quercetin rich apple peel extract. The ingestion of vacuum impregnated apple chips, apple peel extract capsules and apple peel resulted in similar plasma quercetin and plasma total flavonol concentrations compared to the quercetin dihydrate capsule. With regard to the bioavailabilities of all quercetin treatments, a reduced release from vacuum impregnated apple chips can be excluded. The apple peel matrix which is rich in indigestible dietary fibers impacted the profile of the plasma flavonol time curve similar to poor soluble quercetin dihydrate. Finally, the quercetin bioavailability of vacuum impregnated apple chips (AUC0–1440min: 104±24μmol·min∙L−1) as functional food was similar to the supplementation with apple peel extract capsules (AUC0–1440min: 87±27μmol∙min∙L−1).

Bioavailability of the flavonol quercetin in neonatal calves after oral administration of quercetin aglycone or rutin

Polyphenols, such as flavonoids, are secondary plant metabolites with potentially health-promoting properties. In newborn calves flavonoids may improve health status, but little is known about the systemically availability of flavonoids in calves to exert biological effects. The aim of this study was to investigate the oral bioavailability of the flavonol quercetin, applied either as quercetin aglycone (QA) or as its glucorhamnoside rutin (RU), in newborn dairy calves. Twenty-one male newborn German Holstein calves were fed equal amounts of colostrum and milk replacer according to body weight. On d 2 and 29 of life, 9mg of quercetin equivalents/kg of body weight, either fed as QA or as RU, or no quercetin (control group) were fed together with the morning meal. Blood samples were taken before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 12, 24, and 48h after feed intake. Quercetin and quercetin metabolites with an intact flavonol structure (isorhamnetin, tamarixetin, and kaempferol) were analyzed in blood plasma after treatment with glucuronidase or sulfatase by HPLC with fluorescence detection. Maximum individual plasma concentration was depicted from the concentration-time-curve on d 2 and 29, respectively. Additional blood samples were taken to measure basal plasma concentrations of total protein, albumin, urea, and lactate as well as pre- and postprandial plasma concentrations of glucose, nonesterified fatty acids, insulin, and cortisol. Plasma concentrations of quercetin and its metabolites were significantly higher on d 2 than on d 29 of life, and administration of QA resulted in higher plasma concentrations of quercetin and its metabolites than RU. The relative bioavailability of total flavonols (sum of quercetin and its metabolites isorhamnetin, tamarixetin, and kaempferol) from RU was 72.5% on d 2 and 49.6% on d 29 when compared with QA (100%). Calves fed QA reached maximum plasma concentrations of total flavonols much earlier than did RU-fed calves. Plasma metabolites and hormones were barely affected by QA and RU feeding in this experiment. Taken together, orally administrated QA resulted in a greater bioavailability of quercetin than RU on d 2 and 29, respectively, and quercetin bioavailability of quercetin and its metabolites differed markedly between calves aged 2 and 29 d.

Flavonols, alkaloids, and antioxidant capacity of edible wild berberis species from patagonia.

There are 20 species of the Berberidaceae family described in Chile, whose fruits are edible and show high anthocyanin and hydroxycinnamic acid levels. Berberis microphylla G. Forst, commonly known as calafate, is the most extensively distributed. Flavonols and alkaloids in seed, pulp, skin, and whole calafate berry extracts and other Berberis were studied using HPLC-DAD-ESI-MS/MS and HPLC with fluorescence detector. Berry samples from different locations in Chilean Patagonia, including different phenological stages, were systematically addressed. Results were compared with other organs of the plant and with other Berberis species. Total flavonol concentration in calafate (n = 65) was 1.33 ± 0.54 μmol/g. Glycosyl metabolites of quercetin and isorhamnetin were the most abundant. Similar profiles were observed in calafate from distinct locations, but important differences were observed for the other edible Berberis species. Calafate pulp and skin have higher flavonol concentrations than seeds, and the maturation process reduced its levels. TEACCUPRAC and TEACABTS of whole calafate extracts and fractions are also explored. Finally, only berberine was detected in the fruit (0.001%), mainly in seeds. Results contribute to the promotion of this berry as a superfruit from Patagonia.

Influence of cultivar and origin on the flavonol profile of fruits and cladodes from cactus Opuntia ficus-indica

Flavonols are hypothesized to be the most important polyphenolic antioxidants. This present study aimed at investigating flavonols in cactus Opuntia ficus-indica fruits from two Egyptian cultivars in comparison to three common Sicilian cultivars, and two further cultivars from South Africa. Besides, cactus O. ficus-indica cladodes from Egyptian cultivars have been investigated as well. HPLC–DAD analyses showed that cactus O. ficus-indica fruits and cladodes are mainly characterized by isorhamnetin glycosides. These flavonols were found only in the fruit's peel and the cladodes, but not in the pulp. However, all analyzed cultivars exhibited the same flavonol profile which might therefore serve as a chemical fingerprint with regard to genuineness of cactus O. ficus-indica fruits and cladodes or even food products containing whole cactus fruits as ingredients. The findings obtained have been confirmed both by enzymatic hydrolysis of flavonol glycosides following analysis of the aglycons and by HPLC–ESI-MSn. The concentration of total flavonols ranged from 2.2 to 4.1 and 6.3 to 7.6mg/g (dw) in the fruit peels and the cladodes, respectively. Further, fruit peels and cladodes exhibited high total phenolic contents and antioxidant activities compared to those of the fruit pulps. These investigations valorize cactus fruit's peel and cladode in comparison to fruit's pulp, and may further provide additional data for using flavonols in chemotaxonomic studies of cactus Opuntia spp. and authenticity of cactus O. ficus-indica products.

Bioavailability of quercetin from its aglycone and its glucorhamnoside rutin in lactating dairy cows after intraduodenal administration

Because of their health-promoting properties, flavonoids are used in feed supplements for ruminants, although scientific evidence for their efficacy in vivo is limited. It has been shown recently that bioavailability of quercetin is low after ruminal administration in cows because of degradation by the ruminal microbiota. It is unknown whether quercetin could be absorbed from the small intestine in ruminants if degradation is prevented; therefore, we investigated the bioavailability of quercetin after duodenal administration in 6 German Holstein cows. On 88±3d in milk, each cow received equivalent doses of quercetin [9, 18, or 27mg of quercetin equivalents (QE)/kg of body weight] either as quercetin aglycone (QA) or as its glucorhamnoside rutin (RU). In addition, 2 control studies with duodenal administration of NaCl solution (0.9%) were conducted per cow to examine concentrations of flavonoids in plasma during regular feeding. Blood samples were collected at defined time intervals over a period of 24h before and after administration of the test compounds. A washout period of 2d was applied between the runs to avoid possible carryover effects. Concentrations of plasma quercetin aglycone and its metabolites isorhamnetin, tamarixetin, and kaempferol were measured after treatment with glucuronidase/sulfatase by HPLC with fluorescence detection. After administration of RU, levels of plasma quercetin did not increase above baseline, irrespective of dose administered. After duodenal administration of QA, the plasma concentration of QA and its methylated metabolites clearly increased above baseline. The maximal plasma concentrations of total flavonols (about 2h after application) increased in a dose-dependent manner but showed high interindividual variability (range 368.8 to 983.3nmol/L at 27mg of QE/kg of body weight) but peak time did not differ. Preadministration baseline values of total flavonols were reached again 3 to 4h after QA administration. The bioavailability of quercetin and its metabolites, as measured by the area under the concentration–time curve, was affected by the quercetin source applied, whereby quercetin from RU was unavailable. Taken together, duodenal administration enhanced bioavailability of QA almost to values previously reported in pigs after oral administration of QA. In contrast to findings in monogastrics or after oral administration in cows, quercetin from RU seems to be unavailable when administered duodenally.

Effect of thermal treatment on physicochemical composition and sensory qualities, including ‘foxy’ methyl anthranilate of interspecific variety Golden Muscat (Vitis vinifera × Vitis labrusca) fortified wine made in Taiwan

AbstractBACKGROUND: The major defect of the interspecific variety Golden Muscat (Vitis vinifera × Vitis labrusca) is the inheritance of the specific foxy off‐flavours from the parent species Vitis labrusca. Thermal treatment is a traditional method of producing fortified wine that originated from the subtropical Portuguese island of Madeira. This technique was used to treat Golden Muscat fortified wine in order to investigate the effects of thermal treatment on the physicochemical composition and sensory qualities of the wine.RESULTS: The control wine had the lowest total phenol concentration, total flavonol concentration and total acidity. Increased colour intensity in all thermal‐treated samples was detected. The amount of foxy methyl anthranilate in the wine decreased significantly (P &lt; 0.05) after thermal treatment. Panellists indicated that, compared to the control wine, the thermal‐treated wines had higher flavour complexity, flavour intensity, persistence and balance. The control wine exhibited an unpleasant foxy flavour.CONCLUSION: These results suggest that the thermal treatment technique can be used for the production of Golden Muscat fortified wines with desirable flavour. This technique could assist local winemakers to produce an interspecific variety Golden Muscat fortified wine of acceptable quality. Copyright © 2009 Society of Chemical Industry

Effects of fish farming on flavonoids in Posidonia oceanica

This work is a first approach to flavonoid responses (total proanthocyanidins and total and simple flavonols) in Posidonia oceanica in function of nutrient enrichment (aquaculture activities — fish farming), in the western Mediterranean Sea (Calvi–Corsica–France). The first result is the presence of total and simple flavonoids in P. oceanica. The second result shows an increase in total proanthocyanidin and total flavonol concentrations near cages, which would be linked to the high grazing pressure induced by meadow enrichment. Concerning simple flavonols, only quercetin shows a response to fish farming, which could be due to its strong antioxidant capacity. The presence of fish farming, which causes variations in environmental parameters, could affect the functioning of P. oceanica meadows. Flavonoid concentrations in P. oceanica seem to be a possible bioindicator of nutrient enrichment for the management of the littoral environment.

The Effect of Partial Defoliation on Vine Carbohydrate Concentration and Flavonoid Production in Cranberries

The effect of partial defoliation (rate and timing) on vine carbohydrate concentration and the development of phenolic compounds in field-grown `Stevens' cranberry fruit was investigated in two experiments. In Expt. 1, partial defoliation rates of 0%, 18%, 39%, and 53% of total leaf area were applied before new growth, at fruit set, at midfruit development, and preharvest. In Expt. 2, treatments of 0% and 34% removal of new leaves were applied at postfruit set, and at midfruit development. In both experiments, upright samples were harvested for carbohydrate analysis 10d after defoliation, and fruit were removed for analysis before commercial harvest of the site. While total berry phenolic concentration was unaffected by partial defoliation in both studies, the separate pools of flavonoid compounds were affected differently by treatment. In Expt. 1, total flavonol concentration at harvest was improved by the highest rate of partial defoliation (53% of total leaf area) at both fruit set and midfruit development. Total anthocyanin concentration was improved by partial defoliation rates of 39% and 53% of total leaf area compared to the 18% defoliation treatment, but was not affected by timing of defoliation. Pearson correlation coefficients indicated that total flavonol concentration was positively correlated with vine total nonstructural carbohydrate concentration at preharvest, while total anthocyanin concentration was negatively correlated with vine soluble carbohydrates, starch, and total nonstructural carbohydrate concentration at midfruit development. In Expt. 2, total phenolics, flavonols, and anthocyanins were unaffected by partial defoliation; however there was a negative correlation between total anthocyanin concentration in the fruit and soluble carbohydrate concentration in the vine at midfruit development. In these experiments, partial defoliation early in the growing season improved total flavonols and total anthocyanins. Production of flavonols and anthocyanins appeared to be regulated independently of each other.