Pelargonidin Glycosides Research Articles

Characterization of the varied output from the anthocyanin pathway in Phalaenopsis-type Dendrobium hybrids and its relationship with flower coloration

Floral color is an important Phalaenopsis-type Dendrobium hybrids (Den-Phals) trait in the flower markets. Anthocyanins are key pigments contributing to purple, pink, and violet floral color. However, the impact of anthocyanin composition on flower coloration has not yet been fully elucidated. In this study, the flower color characteristics of 62 Den-Phals were evaluated. Most flowers contained purple, while pure blue, orange, and red floral colors were scarce. In total 35 anthocyanins were identified and two acylated pelargonidin glycosides were tentatively characterized using ultra-performance liquid chromatography (UPLC)-mass spectrum (MS) analysis. Unfortunately, the major anthocyanin components remained unidentified. However, the hydrolysis anthocyanins to their anthocyanidins suggested that the cyanidin was the major component in most hybrids with a relative content over 85 %. Pelargonidin was almost the only pigment in reddish pink flowers. The slightly higher peonidin content was found in purple-violet flowers (up to 6.23 %). The trend indicated that with the increase of total anthocyanidin and cyanidin pigments, the floral color deepened and turned to purple. Flavones or flavonols as co-pigments contributed to brighter and yellower color. From the above results, the varied output from the anthocyanin biosynthetic pathway among Den-Phals was used to identify the rate-limiting steps involved and a strategy for the cultivation of pure red, blue, and violet flowers is proposed. The study provides a basis for screening excellent germplasm and improving floral color in Den-Phals.

Widely targeted metabolomics and HPLC analysis elaborated the quality formation of Yunnan pickled tea during the whole process at an industrial scale.

Yunnan pickled tea is produced from fresh tea-leaves through fixation, rolling, anaerobic fermentation and sun-drying. In this study, widely targeted metabolomics using UHPLC-QQQ-MS/MS and HPLC analysis were carried out to elaborate its quality formation during the whole process. Results confirmed the contribution of preliminary treatments and anaerobic fermentation to the quality formation. A total of 568 differential metabolites (VIP>1.0, P<0.05, FC>1.50 or<0.67) were screened through OPLS-DA. (-)-Epigallocatechin and (-)-epicatechin significantly (P<0.05) increased from the hydrolyzation of ester catechins, such as (-)-epigallocatechin gallate and (-)-epicatechin gallate in anaerobic fermentation. Additionally, the anaerobic fermentation promoted vast accumulations of seven essential amino acids, four phenolic acids, three flavones and flavone glycosides, pelargonidin and pelargonidin glycosides, flavonoids and flavonoid glycosides (i.e. kaempferol, quercetin, taxifolin, apigenin, myricetin, luteolin and their glycosides) through relevant N-methylation, O-methylation, hydrolyzation, glycosylation and oxidation.

Chemical Composition and Polyphenol Compounds of Vaccinium floribundum Kunth (Ericaceae) from the Volcano Chimborazo Paramo (Ecuador)

Mortiño (Vaccinium floribundum Kunth) is considered a “superfruit” due to its antioxidant capacity and possible health benefits. To date, there is no known study that addresses the biochemical characterization of mortiño berries from the paramo of the Chimborazo volcano (Ecuador). So, the aim of this research was to evaluate for the first time the effect of the stage of development of the mortiño berries (two stages) and environment of origin (three sampling areas) on fruit quality. Polyphenol compounds were identified by high-performance liquid chromatography (HPLC) coupled to electrospray ionization mass spectrometric (ESI-MSn) and quantified by high-performance liquid chromatography with a diode array detector (HPLC-DAD). Moreover, antioxidant properties (ABTS•+, and DPPH), sugar and organic acids, and minerals were examined. The main organic acids were quinic and citric acid, while glucose, fructose, sucrose, mannose, and sorbitol were the main sugars determined in the mortiño fruits. The main constituents of the mortiño berries included hydroxycinnamic acids (5-O-caffeoylquinic acid), flavonols (quercetin 3-hexoside, quercetin 5-hexoside, quercetin 3-pentoside, and quercetin-3-O-rhamnoside) and anthocyanins. Seven anthocyanins were identified: glycosides of cyanidin, delphinidin, petunidin, peonidin, and pelargonidin. The research confirms that the mortiño berries produced in the Ecuadorian paramo area are a valuable source of polyphenolics, rich in sugars and organic acids, and can be classified as a good source of microelements.

Polyacylated Anthocyanins Derived from Red Radishes Protect Vascular Endothelial Cells Against Palmitic Acid-Induced Apoptosis via the p38 MAPK Pathway

Palmitic acid (PA), a widely consumed saturated fat, is known to induce the apoptosis of vascular endothelial cells. This study examined the protective effect of anthocyanin from red radish (ARR), which has been shown to protect the cardiovascular system and is rich in polyacylated pelargonidin (P) glycosides, on PA-treated SV 40 transfected aortic rat endothelial cells (SVAREC). In all, 22 distinct anthocyanins were identified in the ARR via ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry, the most abundant of which were pelargonidin-3-(p-coumaroyl)diglucoside-5-glucoside (31.60%), pelargonidin-3-(feruloyl)diglucoside-5-(malonyl)glucoside (22.98%), pelargonidin-3-(p-coumaroyl)diglucoside-5-(malonyl)glucoside (8.02%), and pelargonidin-3-(feruloyl)diglucoside-5-glucoside (6.25%). P displayed the highest serum level (93.72%) in the ARR-treated mice, while polyacylated P glucosides were also absorbed intact. Furthermore, ARR treatment effectively increased cellular activity and reduced the ratio of Bcl-2-associated X protein : B cell lymphoma-2, while simultaneously alleviating the excessive production of reactive oxygen species in PA-treated SVAREC. Transcriptome and further verification analyses confirmed that the ARR-inhibiting PA-induced apoptosis of SVAREC was related to the p38 mitogen-activated protein kinase signaling pathway. Our results are the first to demonstrate that ARR may be a promising phytochemical in the prevention of PA-induced endothelial dysfunction.

Colorimetric selective quantification of anthocyanins with catechol/pyrogallol moiety in edible plants upon zinc complexation.

Here is examined the colour development from common anthocyanins (i.e., cyanidin, delphinidin, malvidin, and pelargonidin glycosides) and from anthocyanins-rich extracts (i.e., bilberries, strawberries, and raspberries), using zinc-anthocyanin complexes as molecular probe. We have observed the absorbance increase in the blue region in presence of large excess of zinc ion at acidic pH for cyanidin and delphinidin derivatives, likely due to quinoidal base stabilization from catechol and pyrogallol moiety. The assay condition were studied and applied to natural extracts containing these compounds. The same behaviour was observed for bilberry and, to a minor extent, for raspberry extracts, due to the larger cyanidin/delphinidin contents in the former than in the latter. Anthocyanin standard UV-Vis analysis in buffer has shown a very good linear correlation for cyanidin and delphinidin (R2=0.995 and 0.997, respectively), good precision (CV%=7.4% and 5.3% respectively), high sensitivity (Cyε600nm=8300M-1cm-1, LOD=0.264±0.005mgL-1, LOQ=0.478±0.007mgL-1, and Dpε600nm=15,900M-1cm-1, LOD=0.143±0.002mgL-1, LOQ=0.478±0.007mgL-1). The effectiveness of this colorimetric method for the selective quantification of catechol/pyrogallol-based anthocyanins has been demonstrated in the aforementioned complex real matrices and compared to LC-MS/MS analysis and pH-differential method, offering a valuable tool to characterize plant and food extracts particularly rich in zinc-coordinating anthocyanins.

Colored grains: Chemistry, health benefits and processing

Grains are important part of our diet and among them colored grains are getting more research interest among scientist due to their enhanced nutritional, antioxidant and health promoting properties. According to different studies anthocyanins like cyanidin, malvidin, delphinidin, petunidin, peonidin and pelargonidin glycosides were identified and quantified in different colored grains like rice, maize, barley and wheat mainly by chromatographic and spectroscopic methods. Antioxidant activity of these pigmented grains cereals are measured using DPPH, FRAP, ORAC and ABTS assays and it was found to be related to the total anthocyanin content. Currently researches are being conducted on baked and extruded products from colored cereals like bread, biscuit, muffins, pasta, noodles etc. Application of colored grains are limited in to food colorants and in small scale as functional food products due to the thermal stability related issue of the bioactive compounds in colored grains and this area should be taken more in to consideration to stabilize these compounds and to introduce these pigmented grain based products to consumers in large scale after proper market analysis.

Glycosides changed the stability and antioxidant activity of pelargonidin

Pelargonidin glucosides represent important pigments in the food industry. We compared the pH, metal-ionic, and thermal stability of pelargonidin (Pg), pelargonidin-3-O-glucoside (P3G), pelargonidin-3-O-rutinoside (P3R), and pelargonidin-3,5-O-diglucoside (P35DG) using visible spectrum analysis at 400–700 nm. The results showed that the pH stability of P3G and P3R exceeded Pg and P35DG. Ferrous ion (Fe2+) enhanced the stability of P3G and P3R, while thermal processing-induced degradation was evident in Pg and pelargonidin glycosides, according to the 1.5-order kinetic equation. Moreover, Pg and P35DG displayed higher temperature sensitivity than P3G and P3R. Then, 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity and ferric reducing antioxidant power (FRAP) analysis of the chemical models, and cell activity and reactive oxygen species assays of Caco2 and human umbilical vein endothelial cells (HUVECs) were used to identify the relationship between the pelargonidin structure and antioxidant activity. The DPPH-scavenging activity and FRAP values increased when the number and molecular weight of the pelargonidin glycosides were reduced, increasing the pro-oxidant properties in the Caco2 cells and the antioxidant activity in the HUVECs. Accordingly, this study suggested that glycosides might enhance the stability while decreasing the antioxidant activity of pelargonidin since glycosides increase the steric hindrance during reactions.

An Integrated-Omics/Chemistry Approach Unravels Enzymatic and Spontaneous Steps to Form Flavoalkaloidal Nudicaulin Pigments in Flowers of Papaver nudicaule L.

Flower colour is an important trait for plants to attract pollinators and ensure their reproductive success. Among yellow flower pigments, the nudicaulins in Papaver nudicaule L. (Iceland poppy) are unique due to their rarity and unparalleled flavoalkaloid structure. Nudicaulins are derived from pelargonidin glycoside and indole, products of the flavonoid and indole/tryptophan biosynthetic pathway, respectively. To gain insight into the molecular and chemical basis of nudicaulin biosynthesis, we combined transcriptome, differential gel electrophoresis (DIGE)-based proteome, and ultra-performance liquid chromatography–high resolution mass spectrometry (UPLC-HRMS)-based metabolome data of P. nudicaule petals with chemical investigations. We identified candidate genes and proteins for all biosynthetic steps as well as some key metabolites across five stages of petal development. Candidate genes of amino acid biosynthesis showed a relatively stable expression throughout petal development, whereas most candidate genes of flavonoid biosynthesis showed increasing expression during development followed by downregulation in the final stage. Notably, gene candidates of indole-3-glycerol-phosphate lyase (IGL), sharing characteristic sequence motifs with known plant IGL genes, were co-expressed with flavonoid biosynthesis genes, and are probably providing free indole. The fusion of indole with pelargonidin glycosides was retraced synthetically and promoted by high precursor concentrations, an excess of indole, and a specific glycosylation pattern of pelargonidin. Thus, nudicaulin biosynthesis combines the enzymatic steps of two different pathways with a spontaneous fusion of indole and pelargonidin glycoside under precisely tuned reaction conditions.

Phenolic Composition and Antioxidant Activity of Purple Sweet Potato (Ipomoea batatas (L.) Lam.): Varietal Comparisons and Physical Distribution.

The outer layer of purple sweet potato is removed during processing; however, this layer serves as a potential source of phenolics, especially anthocyanins. Herein, the phenolic composition and antioxidant activity were determined for the inner and outer layers of five purple sweet potato cultivars (‘Sinjami’, ‘Jami’, ‘Danjami’, ‘Yeonjami’, and ‘Borami’) harvested in Korea. Anthocyanins were identified using ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometer (UHPLC-(ESI)-qTOF-MS) and ultra-high-performance liquid chromatography-linear ion trap mass spectrometer (UHPLC-Ion trap-MS), and their composition was quantified using HPLC-coupled with diode array detector (DAD). Non-anthocyanin phenolic compounds (phenolic acids and flavonols) were quantified using UHPLC-(ESI)-triple quadrupole (QqQ). A total of 20 anthocyanins, including non-acylated or acylated peonidin, cyanidin, and pelargonidin glycosides, were identified. Peonidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside was the major anthocyanin, with the highest level in the ‘Sinjami’ cultivar (outer; 12,366 mg/kg DW, inner; 14,832 mg/kg DW). Additionally, 12 phenolic acids and 6 flavonols (quercetin derivatives) were identified, with the outer layers of all cultivars displaying higher total levels than the inner layers. ‘Sinjami’ and ‘Jami’ had higher phenolic acid and quercetin derivative content and antioxidant activities than the other three cultivars (p < 0.05). Thus, the outer layers of ‘Sinjami’ and ‘Jami’ cultivars could be potential sources of anthocyanins and other phenolics.

Effect of vacuum–grinding on the stability of anthocyanins, ascorbic acid, and oxidative enzyme activity of strawberry

In this study, strawberries were ground at vacuum levels of 2.67, 6.67, 13.33, 19.99, and 101.33 kPa (atmospheric pressure) using a specially designed vacuum grinding and continuous packaging device. The grinding at higher vacuum levels led to better maintenance of ascorbic acid and anthocyanins, resulting in a higher antioxidant activity and redness due to the low oxygen availability limiting oxidation. Vacuum-grinding below 2.67 kPa prevented the oxidation of pelargonidin glycosides to a greater degree than that of cyanidin and delphinidin glycoside, due to structural differences related to the number of hydroxyl groups in the B ring, revealing the faster oxidation rate of diphenolic anthocyanins. The model fits indicated a logarithmic rather than a linear degradation as the oxygen level increased, indicating that even small amount of oxygen may cause drastic quality deterioration during grinding. Overall, our results indicate that vacuum grinding at very low oxygen levels is an effective technology to prevent the oxidation of anthocyanins and ascorbic acid, resulting in higher redness and antioxidant activities in strawberries.

Effect of nitrate concentration on plant growth and anthocyanin accumulation in the ornamental bromeliad Alcantarea imperialis

Alcantarea imperialis (Carrière) Harms is a large bromeliad species with showy inflorescence widely used in landscape projects. When grown in vitro under different nitrogen (N) concentrations, its normally green leaves show red coloration. Thus, the aim of this study was to evaluate the in vitro growth of A. imperialis plants and identify the anthocyanins present on their leaves. Plants obtained from seeds were cultivated in vitro for six months in Murashige and Skoog (MS) medium with varying N concentrations (3.75, 7.5, and 15 mM NO3 −) and transferred to the greenhouse where they remained for 12 months. The number of leaves and roots, length of aerial parts and roots, mass of shoot and root parts, photosynthetic pigment contents (chlorophyll a, b, and carotenoids), and anthocyanin levels were determined. During in vitro cultivation, anthocyanin levels increased with increasing N concentrations. The presence of pelargonidin, cyanidin and delphinidin glycosides in A. imperialis leaves was identified by high-performance liquid chromatography (HPLC). Using NO3 − as N source enhanced plant growth and anthocyanin accumulation in A. imperialis.

Co-Microencapsulation of Anthocyanins from Cornelian Cherry Fruits and Lactic Acid Bacteria in Biopolymeric Matrices by Freeze-Drying: Evidences on Functional Properties and Applications in Food

Cornus mas was used in this study as a rich source of health-promoting bioactives. The cornelian cherries were used to extract the polyphenols and anthocyanins. The chromatographic profile of the Cornus mas fruit extract revealed the presence of several anthocyanins, mainly delphinidin, cyanidin and pelargonidin glycosides. The extract was co-microencapsulated with Lactobacillus casei ssp. paracasei in a unique combination of whey protein isolates, inulin and chitosan by freeze-drying, with an encapsulation efficiency of 89.16 ± 1.23% for anthocyanins and 80.33 ± 0.44% for lactic acid bacteria. The pink-red colored powder showed a total anthocyanins content of 19.86 ± 1.18 mg cyanidin-3-glucoside/g dry weight (DW), yielding an antioxidant activity of 54.43 ± 0.73 mMol Trolox/g DW. The viable cells were 9.39 × 109 colony forming units (CFU)/g DW. The confocal microscopy analysis revealed the microencapsulated powder as a complex one, with several large formations containing smaller aggregates, consisting of the lactic acid bacteria cells, the cornelian cherries’ bioactive compounds and the biopolymers. The powder was tested for stability over 90 days, showing a decrease of 50% in anthocyanins and 37% in flavonoids content, with no significant changes in antioxidant activity and CFU. The powder showed a significant inhibitory effect against the α-amylase of 89.72 ± 1.35% and of 24.13 ± 0.01% for α-glucosidase. In vitro digestibility studies showed a significant release of anthocyanins in gastric juice, followed by a decrease in intestinal simulated conditions. The functional properties of the powder were tested by addition into a yogurt, highlighting a higher and more stable antioxidant activity at storage when compared to the control.

Kinetic and Thermodynamic Characteristics of Thermal Degradation of Anthocyanins from Strawberry and Blueberry Commercial Juices

Thermal stabilities of anthocyanins in strawberry and blueberry commercial juices were studied over the temperatures 75, 85 and 95 oC. Results indicated that the thermal degradation of anthocyanins followed the first-order reaction kinetics. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. During heating, anthocyanins in the strawberry juice degraded faster than in blueberry juice, with the activation energies of 74.16 kJ/mol and 65.75 kJ/mol, respectively. Cyanidin-3-glucoside (cyd-3-glu) was more susceptible to the thermal treatment than pelargonidin glycosides in strawberry juice. Delphinidin glycosides were more susceptible to the thermal treatment than cyanidin glycosides in blueberry juice. However, cyd-3-glu in strawberry juice was more sensitive to the thermal treatment than in blueberry juice. Obtained results for activation enthalpies indicated that the degradation process was endothermic and Gibbs free energy of activation indicated that they were not spontaneous.

Differential accumulation of pelargonidin glycosides in petals at three different developmental stages of the orange-flowered gentian (Gentiana lutea L. var. aurantiaca).

Corolla color in Gentiana lutea L. exhibits a yellow/orange variation. We previously demonstrated that the orange petal color of G. lutea L. var. aurantiaca is predominantly caused by newly synthesized pelargonidin glycosides that confer a reddish hue to the yellow background color, derived from the carotenoids. However, the anthocyanin molecules of these pelargonidin glycosides are not yet fully identified and characterized. Here, we investigated the regulation, content and type of anthocyanins determining the petal coloration of the orange-flowered G. lutea L. var. aurantiaca. Anthocyanins from the petals of G. lutea L. var. aurantiaca were characterized and quantified by HPLC-ESI-MS/MS (High-performance liquid chromatography-electrospray ionization-tandem mass spectrometry) coupled with a diode array detector in flowers at three different stages of development (S1, S3 and S5). Eleven pelargonidin derivatives were identified in the petals of G. lutea L. var. aurantiaca for the first time, but quantitative and qualitative differences were observed at each developmental stage. The highest levels of these pelargonidin derivatives were reached at the fully open flower stage (S5) where all anthocyanins were detected. In contrast, not all the anthocyanins were detected at the budlet stage (S1) and mature bud stage (S3) and those corresponded to more complex pelargonidin derivatives. The major pelargonidin derivatives found at all the stages were pelargonidin 3-O-glucoside, pelargonidin 3,5-O-diglucoside and pelargonidin 3-O-rutinoside. Furthermore, the expression of DFR (dihydroflavonol 4-reductase), ANS (anthocyanidin synthase), 3GT (UDP-glucose:flavonoid 3-O-glucosyltransferase), 5GT (UDP-glucose:flavonoid 5-O-glucosyltransferase) and 5AT (anthocyanin 5-aromatic acyltransferase) genes was analyzed in the petals of three developmental stages, showing that the expression level of DFR, ANS and 3GT parallels the accumulation of the pelargonidin glucosides. Overall, this study enhances the knowledge of the biochemical basis of flower coloration in Gentiana species, and lays a foundation for breeding of flower color and genetic variation studies on Gentiana varieties.

Acylated pelargonidin glycosides from the red-purple flowers of Iberis umbellata L. and the red flowers of Erysimum × cheiri (L.) Crantz (Brassicaceae)

Five previously undescribed acylated pelargonidin 3-sophoroside-5-glucosides (pigments 2–6) were isolated from the red-purple flowers of Iberis umbellata L. ‘Candycane Rose’ and ‘Candycane Red’, in addition to a known one (pigment 1). The structures of five undescribed acylated anthocyanins were determined by chemical and spectroscopic methods to be pelargonidin 3-O-[2-O-(2-O-(“acyl-A”)-β-glucopyranosyl)-6-O-(“acyl-B”)-β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside], in which the “acyl-A” group was either trans-sinapic (2), trans-ferulic (3), trans-sinapic (4), trans-ferulic (5), or trans-ferulic acid (6), and “acyl-B” was either glucosyl-trans-p-coumaric acid (2), glucosyl-trans-p-coumaric acid (3), trans-feruloyl-glucosyl-trans-p-coumaric acid (4), trans-feruloyl-glucosyl-trans-p-coumaric acid (5), or glucosyl-trans-feruloyl-glucosyl-trans-p-coumaric acid (6). Moreover, three previously undescribed acylated pelargonidin 3-sambubioside-5-glucosides (pigments 7, 8, and 10) and one undescribed acylated pelargonidin 3-(3X-glucosylsambubioside)-5-glucoside (pigment 9) were isolated from the red flowers of Erysimum × cheiri (L.) Crantz ‘Aurora’ as major anthocyanins. The structures of the three undescribed acylated pelargonidin 3-sambubioside-5-glucosides were determined to be pelargonidin 3-O-[2-O-(2-O-(“acyl-C”)-β-xylopyranosyl)-6-O-(“acyl-D”)-β-glucopyranoside]-5-O-(β-glucopyranoside), in which the “acyl-C” group was either non (7), non (8), or trans-p-coumaric acid (10) and “acyl-D” was either trans-p-coumaric (7), trans-ferulic (8), or trans-p-coumaric acid (10). Moreover, a previously undescribed acylated pelargonidin 3-(3X-glucosylsambubioside)-5-glucoside was identified to be pelargonidin 3-O-[2-O-(2-O-(trans-p-coumaroyl)-3-O-(β-glucopyranosyl)-β-xylopyranosyl)-6-O-(trans-p-coumaroyl)-β-glucopyranoside]-5-O-(β-glucopyranoside) (9). In addition, the distribution of anthocyanidins structural elements in 24 Brassicaceous species is compared.

Chemical composition of the edible flowers, pansy (Viola wittrockiana) and snapdragon (Antirrhinum majus) as new sources of bioactive compounds

The nutritional composition - including total and individual phenolic compounds, carotenoids, and the antioxidant capacity – of two commercially available edible flowers, pansy and snapdragon, was studied. The edible flowers did not differ in their carbohydrates, fat, or ash contents, or in total energy, but pansy had higher values of moisture, protein, and total dietary fiber than snapdragon. Phenolic compounds were more abundant in pansy than in snapdragon, and flavonoids were the major compounds, followed by anthocyanins. The phenolic profile of pansy included flavonols, such as quercetin and isorhamnetin glycosides, flavones, such as apigenin glycosides, and anthocyanins, such as cyanidin and delphinidin glycosides; in snapdragon it included flavonol glycosides (e.g. quercetin and kaempferol glycosides) and anthocyanins, such as cyanidin and pelargonidin glycosides. The contents of total carotenoids were 146 and 29 µg/mg for pansy and snapdragon, respectively, and lutein was the dominant compound.

The effect of dietary factors on strawberry anthocyanins oral bioavailability.

Strawberries are a dietary source of anthocyanins, particularly pelargonidin glycosides. Dietary anthocyanins have received increasing attention among researchers and consumers due to their health benefits. The oral bioavailability of anthocyanins is reported to be low and various dietary factors may influence their oral bioavailability further. Milk is suggested to reduce (poly)phenols' oral bioavailability. However, the effect of milk on anthocyanin oral bioavailability remains uncertain. Likewise, mixed nutrient meals may influence the oral bioavailability of anthocyanins. Therefore, the purpose of this study was to assess the effect of milk on the oral bioavailability and other pharmacokinetic (PK) variables of strawberry anthocyanins consumed with and without a meal. Nine healthy participants consumed a strawberry beverage prepared in milk or water with a standard meal on two occasions. On two additional occasions, the beverages were given to a subset (n = 4) of participants to determine the impact of the meal on anthocyanin PK variables, including oral bioavailability. Independent of the meal, beverages prepared in milk significantly reduced the peak plasma concentrations (Cmax) of pelargonidin-3-O-glucoside (P-3-G), pelargonidin-glucuronide (PG) and pelargonidin-3-O-rutinoside (P-3-R), as well as the PG and P-3-R area under the curve (AUC) (p < 0.05) compared to beverages prepared in water. Milk did not influence the oral relative bioavailability of pelargonidin anthocyanins under meal conditions; however, the oral relative bioavailability of pelargonidin anthocyanins was reduced by ∼50% by milk under without meal conditions (p < 0.05). Consuming strawberry beverages made with milk and consuming those made with water with and without a meal influenced different aspects of strawberry anthocyanin PKs. The significance of this effect on clinical efficacy requires additional research.

Effect of cultivar and storage temperature on identification and stability of polyphenols in strawberry cloudy juices

The effect of strawberry (Fragaria x ananassa Duchesne) cultivars (cvs) and storage temperature on the stability of polyphenols in cloudy juices was determined. Identification of phenolic compounds by ultra performance liquid chromatography-electrospray ionization/mass spectrometry (UPLC–ESI/MS), as well as quantitative analysis by ultra-performance liquid chromatography–photodiode array–fluorescence (UPLC–PDA–FL), were carried out on fresh and stored products (6 months, 4°C and 20°C) from 7 different strawberry cvs. A total of 32 polyphenolic compounds were identified: flavan-3-ols (6), anthocyanins (8), flavonols (4) and flavones (3), hydroxycinnamic acids (4), and ellagic acid derivatives (7). Total polyphenol content ranged from 642.08mg/L in fresh ‘Florence’ cv. juice to 296.72mg/L in ‘Honeoye’ cv. juice after 6 months of storage at 20°C. Anthocyanins (max. 161.40mg/L in ‘Honeoye’ juice) demonstrated the greatest degree of degradation (31–100%, depending on the molecular structure and temperature). Cyanidin-3-malonylglucoside was less labile than 3-glucoside. In the case of pelargonidin glycosides, 3-glucoside was more stable. The degradation process was the least advanced in ‘Kimberly’ cv. juice (58.53% at 4°C). Storage conditions also influenced the decrease in p-coumaroyl-hexose, and quercetin-glucuronide content. However, low temperatures limited this process. This was especially noticeable in ‘Florence’ and ‘Honeoye’ cvs. In turn, proanthocyanidins showed the most stability and were the main polyphenols identified in juices (212–434mg/L). Generally, it was observed that the total content of polyphenols and their stability in juices was dependent on the cultivar, and the duration of storage conditions.

Red Anthocyanins and Yellow Carotenoids Form the Color of Orange-Flower Gentian (Gentiana lutea L. var. aurantiaca).

Flower color is an important characteristic that determines the commercial value of ornamental plants. Gentian flowers occur in a limited range of colors because this species is not widely cultivated as a cut flower. Gentiana lutea L. var. aurantiaca (abbr, aurantiaca) is characterized by its orange flowers, but the specific pigments responsible for this coloration are unknown. We therefore investigated the carotenoid and flavonoid composition of petals during flower development in the orange-flowered gentian variety of aurantiaca and the yellow-flowered variety of G. lutea L. var. lutea (abbr, lutea). We observed minor varietal differences in the concentration of carotenoids at the early and final stages, but only aurantiaca petals accumulated pelargonidin glycosides, whereas these compounds were not found in lutea petals. We cloned and sequenced the anthocyanin biosynthetic gene fragments from petals, and analyzed the expression of these genes in the petals of both varieties to determine the molecular mechanisms responsible for the differences in petal color. Comparisons of deduced amino acid sequences encoded by the isolated anthocyanin cDNA fragments indicated that chalcone synthase (CHS), chalcone isomerase (CHI), anthocyanidin synthase 1 (ANS1) and ANS2 are identical in both aurantiaca and lutea varieties whereas minor amino acid differences of the deduced flavonone 3-hydroxylase (F3H) and dihydroflavonol 4-reductase (DFR) between both varieties were observed. The aurantiaca petals expressed substantially higher levels of transcripts representing CHS, F3H, DFR, ANS and UDP-glucose:flavonoid-3-O-glucosyltransferase genes, compared to lutea petals. Pelargonidin glycoside synthesis in aurantiaca petals therefore appears to reflect the higher steady-state levels of pelargonidin synthesis transcripts. Moreover, possible changes in the substrate specificity of DFR enzymes may represent additional mechanisms for producing red pelargonidin glycosides in petals of aurantiaca. Our report describing the exclusive accumulation of pelargonidin glycosides in aurantiaca petals may facilitate the modification of gentian flower color by the production of red anthocyanins.

Unprecedented Utilization of Pelargonidin and Indole for the Biosynthesis of Plant Indole Alkaloids.

Nudicaulins are a group of indole alkaloid glycosides responsible for the color of yellow petals of Papaver nudicaule (Iceland poppy). The unique aglycone scaffold of these alkaloids attracted our interest as one of the most unusual flavonoid‐indole hybrid structures that occur in nature. Stable isotope labeling experiments with sliced petals identified free indole, but not tryptamine or l‐tryptophan, as one of the two key biosynthetic precursors of the nudicaulin aglycone. Pelargonidin was identified as the second key precursor, contributing the polyphenolic unit to the nudicaulin molecule. This finding was inferred from the temporary accumulation of pelargonidin glycosides in the petals during flower bud development and a drop at the point in time when nudicaulin levels start to increase. The precursor‐directed incorporation of cyanidin into a new 3′‐hydroxynudicaulin strongly supports the hypothesis that anthocyanins are involved in the biosynthesis of nudicaulins.