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Green extraction primarily emphasizes developing new extraction techniques that consume less energy. It involves using safe, non‐toxic alternative solvents and sustainable natural resources to ensure the production of safe and high‐quality extracts. Red onion skin is an important source of anthocyanins, a subgroup of phenolic compounds. Anthocyanins are an important group of natural pigments that have attracted a lot of attention due to their health benefits. However, the instability and high sensitivity of these pigments have limited their use in food and cosmetics. Therefore, in this study, various modern green extraction methods were used, including solvent extraction, ultrasound‐assisted extraction, subcritical water extraction, microwave‐assisted extraction (MAE), pulsed electric field extraction, supercritical fluid extraction (SFE), and high hydrostatic pressure‐assisted (HHPAE) extraction, to specifically extract and purify anthocyanins. The extraction efficiency, specifically targeting anthocyanins, showed the highest efficiency with HHPAE (81.84%) and the lowest with MAE (40.01%). Measurement of total anthocyanin content revealed that HHPAE and SFE methods yielded the highest anthocyanin concentrations, with 248.49 and 244.98 mg/L, respectively. Identification of anthocyanin by LC–MS revealed that the main anthocyanidins in red onion peel are pelargonidin, cyanidin, delphinidin, and petunidin. These results indicate that innovative green extraction methods, particularly HHPAE and SFE, can effectively replace conventional techniques due to their superior efficiency and enhanced preservation of anthocyanin compounds. [ABSTRACT FROM AUTHOR]

Cyanidin‐3‐O‐glucoside (C3G), as a typical anthocyanin, exhibits excellent antioxidant effects. This study aimed to demonstrate the role and mechanism of C3G in regulating 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase (HMGCR)‐mediated cholesterol anabolism on H2O2‐induced oxidative stress in HEK‐293T cells. Firstly, the inhibitory effect of C3G on oxidative stress was confirmed by CCK‐8, ROS, and mitochondrial membrane potential (MMP) experiments. Then, proteomics was used to investigate and screen differentially expressed proteins in inhibiting cellular oxidative stress by C3G. HMGCR was screened as a key differentially expressed protein by proteomic analysis. The results verified that C3G could reduce cholesterol levels by inhibiting sterol regulatory element‐binding protein (SREBP2)/HMGCR pathway, increasing ATP, and reducing acetyl‐CoA. Finally, HMGCR had been shown to positively increase ROS accumulation and decrease MMP, which were reversed by intervention of C3G through a series of knockdown and overexpression experiments. In conclusion, the results demonstrated that C3G could inhibit the disorder of cholesterol synthesis in oxidative stress cells by regulating the ROS/SREBP2/HMGCR pathway. [ABSTRACT FROM AUTHOR]

Proanthocyanidins (PA) are polyphenol compounds that are widely distributed in the bark, fruit core, skin, or seeds of various plants. Anthocyanidins are water‐soluble natural pigments widely found in plants. They are all flavonoids, a major coloring substance in plants and fruits. In recent years, research into PA and anthocyanins has become increasingly popular because of their excellent anti‐oxidation, scavenging of reactive oxygen free radicals and other physical and chemical activities, and their anti‐cancer, vision protection, aging prevention, skin beauty pharmacological, and nutraceutical effects. Especially, recent systematic reviews and meta‐analyses indicate their value, safety, and efficacy in the prevention, adjuvant therapy, and management of cardiometabolic disease. Here, we summarize their research progress from the aspects of chemical structure, biosynthetic pathways, distribution, extraction and separation, coloration, efficacy, and potential. The comparison between them might provide a reference for their development and efficient utilization. However, more large‐sample‐size randomized controlled trials and high‐quality studies are needed to firmly establish their clinical efficacy. [ABSTRACT FROM AUTHOR]

Summary: Naturally coloured cotton (NCC) fibres need little or no dyeing process in textile industry to low‐carbon emission and are environment‐friendly. Proanthocyanidins (PAs) and their derivatives were considered as the main components causing fibre coloration and made NCCs very popular and healthy, but the monotonous fibre colours greatly limit the wide application of NCCs. Here a G. hirsutum empurpled mutant (HS2) caused by T‐DNA insertion is found to enhance the anthocyanidins biosynthesis and accumulate anthocyanidins in the whole plant. HPLC and LC/MS‐ESI analysis confirmed the anthocyanidins methylation and peonidin, petunidin and malvidin formation are blocked. The deficiency of GhOMT1 in HS2 was associated with the activation of the anthocyanidin biosynthesis and the altered components of anthocyanidins. The transcripts of key genes in anthocyanidin biosynthesis pathway are significantly up‐regulated in HS2, while transcripts of the genes for transport and decoration were at similar levels as in WT. To investigate the potential mechanism of GhOMT1 deficiency in cotton fibre coloration, HS2 mutant was crossed with NCCs. Surprisingly, offsprings of HS2 and NCCs enhanced PAs biosynthesis and increased PAs levels in their fibres from the accumulated anthocyanidins through up‐regulated GhANR and GhLAR. As expected, multiple novel lines with improved fibre colours including orange red and navy blue were produced in their generations. Based on this work, a new strategy for breeding diversified NCCs was brought out by promoting PA biosynthesis. This work will help shed light on mechanisms of PA biosynthesis and bring out potential molecular breeding strategy to increase PA levels in NCCs. [ABSTRACT FROM AUTHOR]

In order to facilitate the development of cotton (Gossypium hirsutum L.) strains with colored fiber, the genetic and developmental control of flavonoids in fibers must be understood. The major goal of this study was to determine whether anthocyanidins accumulate in three different natural colored cotton fibers during their development, and to document the expression levels of flavonoid genes necessary for the production of anthocyanidins to determine if differences in expression levels reflect differences in anthocyanidin production. Most flavonoid structural genes were more highly expressed during fiber elongation than before the beginning of secondary cell wall formation. High performance liquid chromatography (HPLC) analyses showed that the abundance of anthocyanidins was higher in brown fibers than in green or white fibers. Anthocyanidins were present at high levels in fibers, starting at 20 d post‐anthesis of fiber development, which is almost at the end of the fiber elongation stage. Brown cotton contains higher delphinidin levels than of green and white cotton. This pattern is consistent with greater expression of anthocyanin pathway genes in brown fibers. In naturally colored cotton, the enzyme Lar (leucoanthocyanidin reductase) converted leucoanthocyanidins to catechin, which are proanthocyanins (PAs) precursor subunits. It is suggested that failure to produce anthocyanins is likely due to a combination of insufficient expression of Ufgt (UDP‐glucose: flavonoid 3‐O‐glucosyltransferase) and high expression of Lar and Anr (anthocyanidin reductase). [ABSTRACT FROM AUTHOR]

Accumulation of certain phenolics is a well‐known response of plants to enhanced UVB radiation (280–315 nm), but few experiments have compared the relative importance of different phenolic groups for UVB resilience. To study how an altered phenolic profile affects the responses and resilience of silver birch (Betula pendula) to enhanced UVB, we used RNA interference (RNAi) targeting dihydroflavonol reductase (DFR), anthocyanidin synthase (ANS), or anthocyanidin reductase (ANR) to change the accumulation of phenolics. The unmodified control line and RNAi‐modified plants were grown for 51 days under ambient or +32% enhanced UVB dose in a greenhouse. RNAi greatly affected phenolic profile and plant growth. There were no interactive effects of RNAi and UVB on growth or photosynthesis, which indicates that the RNAi and unmodified control plants were equally resilient. UVB enhancement led to an accumulation of foliar flavonoids and condensed tannins, and an increase in the density of stem glands and glandular trichomes on upper leaf surfaces in both the control and RNAi‐modified plants. Our results do not indicate a photoprotective role for condensed tannins. However, decreased growth of high‐flavonoid low‐tannin DFRi and ANRi plants implies that the balance of flavonoids and condensed tannins might be important for normal plant growth. [ABSTRACT FROM AUTHOR]

Summary: The colour‐fleshed potatoes represent a good raw material for the extraction of juices with a high content of biologically active compounds and a high antioxidant activity. The blue‐fleshed potatoes turned out to be a rich source of total polyphenols, as they had approximately 3.5 times higher content of identified anthocyanidins. Regardless of anthocyanin composition, all juices made of colour‐fleshed potatoes were highly stable. Both, high temperature, exposure time to these temperatures, and medium pH had no significant effect on changes in total polyphenols content of potato juices. The juices examined, especially these made of blue‐fleshed potatoes, demonstrated a higher ABTS+ stability during their heating than during pH changes. In addition, a higher antioxidant activity of juices was determined at neutral and alkaline than at acidic pH value of the medium. [ABSTRACT FROM AUTHOR]

The ultrasonic extraction (UE) technology, possessed the advantages of effective, energy‐saving, and environmental‐friendly, was applied to extract the anthocyanin from Lycium ruthenicum (LR). The extraction parameters of UE were optimized by response surface methodology (RSM) with Box–Behnken design (BBD). Anthocyanin composition in LR fruits grown in China was systematically identified and quantified by HPLC‐ESI‐MS. The result showed that PRG was the major anthocyanin, and delphinidin, petunidin, and malvidin were the major anthocyanidins in LR fruits. There was the same anthocyanin composition of LR and great variation in anthocyanins content of LR from different areas in China. However, there was no significant difference between wild and cultivated LR in the same region. A clear separation of LR according to geographical origins was revealed by hierarchical cluster analysis (HCA) and principal component analysis (PCA), and the discrimination model for the anthocyanin concentrations were developed using these two analysis methods. Furthermore, on‐line HPLC‐DPPH assay and scavenging activity of three kinds of radicals (DPPH·, ·OH, and O2-·) in vitro were well applied to evaluate the antioxidant activity of the LR anthocyanin extract (LRAE). And its results indicated the LRAE could be a credible antioxidant agent for applications in cosmetics, food, and medicine. [ABSTRACT FROM AUTHOR]

Summary: Red rice contains high levels of proanthocyanidins and anthocyanins, which have been recognized as health‐promoting nutrients. The red coloration of rice grains is controlled by two complementary genes, Rc and Rd. The RcRd genotype produces red pericarp in wild species Oryza rufipogon, whereas most cultivated rice varieties produce white grains resulted from a 14‐bp frame‐shift deletion in the seventh exon of the Rc gene. In the present study, we developed a CRISPR/Cas9‐mediated method to functionally restore the recessive rc allele through reverting the 14‐bp frame‐shift deletion to in‐frame mutations in which the deletions were in multiples of three bases, and successfully converted three elite white pericarp rice varieties into red ones. Rice seeds from T1 in‐frame Rc lines were measured for proanthocyanidins and anthocyanidins, and high accumulation levels of proanthocyanidins and anthocyanidins were observed in red grains from the mutants. Moreover, there was no significant difference between wild‐type and in‐frame Rc mutants in major agronomic traits, indicating that restoration of Rc function had no negative effect on important agronomic traits in rice. Given that most white pericarp rice varieties are resulted from the 14‐bp deletion in Rc, it is conceivable that our method could be applied to most white pericarp rice varieties and would greatly accelerate the breeding of new red rice varieties with elite agronomic traits. In addition, our study demonstrates an effective approach to restore recessive frame‐shift alleles for crop improvement. [ABSTRACT FROM AUTHOR]

We report herein a detailed structural study by collision-induced dissociation (CID) of nonglycosylated anthocyanins (anthocyanidins) using electrospray ionization triple quadrupole mass spectrometry (ESI-QqQ) and isotope labeling experiments to understand the fragmentation process often used in mass spectrometry analysis of this class of compounds. Tandem mass spectrometric product ion spectra for three anthocyanidins (cyanidin, delphynidin, and pelargonin) were evaluated to propose fragmentation mechanisms to this natural colorant class of organic compounds. The proposed rearrangements, retro Diels-Alder reaction, water loss, CO losses, and stable acylium ion formation, were evaluated based on tandem mass spectrometric experiments of normal and labeled precursor ions together to computational thermochemistry. B3LYP/6-311 + G** ab initio calculations studies were carried out to obtain energy diagrams to show the viability of the proposed mechanisms. The CO losses fragmentation channels have lower energies when compared with water losses and the other proposed fragmentations. The isotope labeling experiments indicate the H/D exchange of the hydroxyl protons and corroborate the proposed general fragmentation mechanism for anthocyanidins. [ABSTRACT FROM AUTHOR]

Abstract: Delphinidin is major anthocyanidin that is extracted from many pigmented fruits and vegetables. This substance has anti‐oxidant, anti‐inflammatory, anti‐angiogenic, and anti‐cancer properties. In addition, delphinidin strongly suppresses the migration and invasion of various cancer cells during tumorigenesis. Although delphinidin has anti‐cancer effects, little is known about its functional roles in osteosarcoma (OS). For these reasons, we have demonstrated the effects of delphinidin on OS cell lines. The effects of delphinidin on cell viability and growth of OS cells were assessed using the MTT assay and colony formation assays. Hoechst staining indicated that the delphinidin‐treated OS cells were undergoing apoptosis. Flow cytometry, confocal microscopy, and a western blot analysis also indicated evidence of apoptosis. Inhibition of cell migration and invasion was found to be associated with epithelial‐to‐mesenchymal transition (EMT), observed by using a wound healing assay, an invasion assay, and a western blot analysis. Furthermore, delphinidin treatment resulted in a profound reduction of phosphorylated forms of ERK and p38. These findings demonstrate that delphinidin treatment suppressed EMT through the mitogen‐activated protein kinase (MAPK) signaling pathway in OS cell lines. Taken together, our results suggest that delphinidin strongly inhibits cell proliferation and induces apoptosis. Delphinidin treatment also suppresses cell migration and prevents EMT via the MAPK‐signaling pathway in OS cell lines. For these reasons, delphinidin has anti‐cancer effects and can suppress metastasis in OS cell lines, and it might be worth using as an OS therapeutic agent. [ABSTRACT FROM AUTHOR]

B Front cover image: b A flavonoid O-methyltransferase (GhOMT1) in I Gossypium hirsutum i is found to play a critical role in anthocyanidin methylation. The multi-colored cotton fibers were selectively bred from the progeny of the empurpled mutant of I GhOMT1 i deficiency crossed with NCCs. Deficiency of I GhOMT i blocks the anthocyanidins methylation, increases anthocyanidins accumulation and enhances PAs biosynthesis in fibers of NCCs. [Extracted from the article]

Wine colour is one of the main organoleptic characteristics influencing its quality. It is of special interest in red vinifications due to the economic resources that wineries have to invest for the extraction of the phenolic compounds responsible for wine colour, compounds that are mainly located inside the skin cell vacuoles, where the volatile compounds are also found. The transfer of phenolic compounds from grapes to must during vinification is closely related to the type of grapes and the winemaking technique. During traditional winemaking, grapes are crushed and skin macerated for several days, with pumps overs to facilitate the colour extraction. To increase this extraction, some chemical (maceration enzymes) or physical technologies (thermovinification, cryomaceration, flash-expansion) can be applied. In this work, a new methodology has been tested. This methodology consists in the application of high-power ultrasounds to crushed grapes to increase the extraction of phenolic compounds. Crushed grapes were treated with this non-thermal technology and vinified, with 3, 6 and 8 days of skin maceration time, and the results were compared with a control vinification, where crushed grapes were not subjected to any treatment and were skin macerated during 8 days. The wine chromatic characteristics (determined spectrophotometrically) and the individual phenolic compounds (anthocyanins and tannins, determined by HPLC) were followed during the maceration period, at the end of alcoholic fermentation and after two months in bottle. Also, the wine volatile compounds were determined by GC- MS. The wines made with ultrasound-treated grapes showed differences with the control wine, especially regarding total phenol content and tannin content. The wines elaborated with sonicated grapes and with only three days of skin maceration time presented similar concentration of anthocyanins and twice the concentration of tannins than control wines elaborated with 8 days of skin maceration. [ABSTRACT FROM AUTHOR]

There are large differences between flavonoids to protect against apoptosis, a process in which cytochrome c (Cyt c) plays a key role. In this work, we show that 7 of 13 flavonoids studied have a capacity to reduce Cyt c similar or higher than ascorbate, the flavonols quercetin, kaempferol and myricetin, flavanol epigallocatechin-gallate, anthocyanidins cyanidin and malvidin, and the flavone luteolin. In contrast, the kaempferol 3( O)- and 3,4′( O)-methylated forms, the flavanone naringenin, and also apigenin and chrysin, had a negligible reducing capacity. Equilibrium dialysis and quenching of 1,6-diphenyl-1,3,5-hexatriene fluorescence experiments showed that flavonoids did not interfere with Cyt c binding to cardiolipin (CL)/phosphatidylcholine (PC) vesicles. However, the CL-induced loss of Cyt c Soret band intensity was largely attenuated by flavonoids, pointing out a stabilizing action against Cyt c unfolding in the complex. Moreover, flavonoids that behave as Cyt c reductants also inhibited the pro-apoptotic CL-induced peroxidase activity of Cyt c, indicating that modulation of Cyt c signaling are probable mechanisms behind the protective biological activities of flavonoids. © 2016 BioFactors, 43(3):451-468, 2017 [ABSTRACT FROM AUTHOR]

BACKGROUND Blueberry products have various health benefits due to their high content of dietary anthocyanins. The aim of this study was to investigate the impact of fermentation and sterilization on total anthocyanin content, composition and some quality attributes of blueberry puree. The blueberry puree used here was fermented for 40 h at 37 °C by Lactobacillus after sterilization. The method of ultra-performance liquid chromatography-mass spectrometry was optimized for the rapid analysis of anthocyanins. Quality attributes including pH, color, total soluble solids and viscosity were measured. RESULTS A total of 21 anthocyanins and five anthocyanidins were quantified by ultra-performance liquid chromatography. Fermented blueberry had reduced total anthocyanin content (29%) and levels of individual anthocyanins compared with fresh blueberry. Total anthocyanin content was decreased 46% by sterilization, and different degradation behavior of individual anthocyanin was appeared between fermented and sterilized-fermented blueberry puree. Fermentation and sterilization decreased the total soluble solids and pH and changed color parameters, while minimally influencing viscosity. CONCLUSIONS The loss of total anthocyanin content by fermentation was related to the unstable structure of blueberry anthocyanins. Anthocyanins are sensitive to temperature (>80 °C), and degradation of anthocyanins by sterilization in blueberry should be considered in the fermentation procedure. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND High antioxidant content and keen marketing have increased blueberry demand and increased local production which in turn mandates new uses for abundant harvests. Pilot scale processes were employed to investigate the anthocyanidin profiles, qualitative volatile compositions, and sensorial attributes in not-from-concentrate ( NFC) 'Tifblue' rabbiteye blueberry juices. RESULTS Processing prior to pasteurization generally resulted in increased L* and hue angle color, while a*, b*, and C* decreased. After 4 months pasteurized storage, non-clarified juice ( NCP) lost 73.8% of total volatiles compared with 70.9% in clarified juice ( CJP). There was a total anthocyanidin decrease of 84.5% and 85.5% after 4 months storage in NCP and CJP, respectively. Storage itself resulted in only 14.2% and 7.2% anthocyanidin loss after pasteurization in NCP and CJP. Storage significantly affected nine flavor properties in juices; however, there were no significant differences in the blueberry, strawberry, purple grape, floral, sweet aroma, or sweet tastes between processed and stored juices. CONCLUSIONS NFC pasteurized blueberry juices maintained desirable flavors even though highly significant volatile and anthocyanidin losses occurred through processing. Maintenance of color and flavor indicate that NFC juices could have an advantage over more abusive methods often used in commercial juice operations. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the association between total flavonoids/flavonoid subclasses intake and prostate cancer risk. Several databases were searched to select eligible studies with predefined criteria. Risk ratios ( RRs) with 95% confidence intervals ( CIs) were used as the effect size. Publication bias and sensitivity analysis were performed. A total of five studies including four prospective cohort studies and one case-control study were included in the meta-analysis. The pooled result demonstrated a significantly increased risk of prostate cancer with higher intake of total flavonoids ( RR = 1.12, 95% CI: 1.02-1.23, P = 0.013). However, sensitivity analysis indicated that there lacked a significant association after removing the study of Wang et al. ( RR = 1.17, 95% CI: 0.94-1.46). Subgroup analysis stratified by flavonoids subclasses found that higher intake of anthocyanidins and flavan-3-ols were significantly associated with increased prostate cancer risk ( RR = 1.12, 95% CI: 1.03-1.21, P = 0.011; RR = 1.21, 95% CI: 1.10-1.32, P < 0.001). Sensitivity analysis also indicated that after removing Wang's study, no significant association between anthocyanidins intake and prostate cancer risk was detected ( RR = 1.22, 95% CI: 0.97-1.54). In conclusion, higher intake of flavonoids may not be associated with prostate cancer risk. [ABSTRACT FROM AUTHOR]

Anthocyanins are water-soluble pigments that are liable for colors ranging from red to blue of most fruits, vegetables, and flowers. A novel and fast method was developed for the determination of five anthocyanins and free pelargonidin by high-performance liquid chromatography coupled to photodiode array detection. A 10% formic acid and acetonitrile mixture was employed as mobile phase in the gradient elution mode. Mobile phase composition, column temperature, flow rate, injection volume, and column conditioning time were optimized by employing a stepwise strategy. Using a C18 core-shell column (100 × 4.6 mm, 2.7 μm), the separation of six analytes was accomplished in less than 9.5 min with a run-to-run analysis time of 19 min. The developed method was validated with respect to linearity ( r > 0.9999), limit of detection, limit of quantification, intra-/interday precision (<2%), accuracy (98.6-104.4%), and specificity. Afterwards, the method was applied to the determination of anthocyanins present in 15 different samples including fruits, fruit juices, and fruit wines. [ABSTRACT FROM AUTHOR]

The effect of methyl, hydroxyl, and chloride substituents in position 3 of the 3′,4′,7-trihydroxyflavylium core structure was studied. The stability, relative energy of each of chemical species (thermodynamics), and their rates of interconversion (kinetics) are very dependent on these substituents. By comparing the mole fraction distribution at equilibrium of the three multistate systems with the parent 3′,4′,7-trihydroxyflavylium, introduction of a methyl substituent in position 3 increases the mole fraction of hemiketal at the expense of the trans-chalcone and increases the hydration rate very significantly; a hydroxyl substituent in position 3 gives rise to a degradation process, as observed in anthocyanidins. In the case of 3-chloro-3′,4′,7-trihydroxyflavylium, a dramatic increase of the flavylium cation acidity was observed and a photochromic system can be operated upon irradiation of the respective trans-chalcone in 1 m HCl. According to the photochromic response of 3,3′,4′,7-tetrahydroxyflavylium and 3′,4′,7-trihydroxyflavylium, some requirements for a good photochromic performance are discussed. [ABSTRACT FROM AUTHOR]

Mt PAR is a proanthocyanidin ( PA) biosynthesis regulator; the mechanism underlying its promotion of PA biosynthesis is not fully understood. Here, we showed that Mt PAR promotes PA production by a direct repression of biosynthesis of isoflavones, the major flavonoids in legume, and by redirecting immediate precursors, such as anthocyanidins, flux into PA pathway. Ectopic expression of Mt PAR repressed isoflavonoid production by directly binding and suppressing isoflavone biosynthetic genes such as isoflavone synthase ( IFS). Meanwhile, Mt PAR up-regulated PA-specific genes and decreased the anthocyanin levels without altering the expression of anthocyanin biosynthetic genes. Mt PAR may shift the anthocyanidin precursor flux from anthocyanin pathway to PA biosynthesis. Mt PAR complemented PA-deficient phenotype of Arabidopsis tt2 mutant seeds, demonstrating their similar action on PA production. We showed the direct interactions between Mt PAR, Mt TT8 and Mt WD40-1 proteins from Medicago truncatula and Glycine max, to form a ternary complex to trans-activate PA-specific ANR gene. Finally, Mt PAR expression in alfalfa ( Medicago sativa) hairy roots and whole plants only promoted the production of small amount of PAs, which was significantly enhanced by co-expression of Mt PAR and Mt LAP1. Transcriptomic and metabolite profiling showed an additive effect between Mt PAR and Mt LAP1 on the production of PAs, supporting that efficient PA production requires more anthocyanidin precursors. This study provides new insights into the role and mechanism of Mt PAR in partitioning precursors from isoflavone and anthocyanin pathways into PA pathways for a specific promotion of PA production. Based on this, a strategy by combining Mt PAR and Mt LAP1 co-expression to effectively improve metabolic engineering performance of PA production in legume forage was developed. [ABSTRACT FROM AUTHOR]

P-glycoprotein (P-gp) inhibition represents a promising therapeutic strategy for oncologic patients. The inhibition by naturally occurring anthocyans would bring certain benefits. Unfortunately, due to the low bioavailability and consequently low blood level, they cannot be used for cancer therapy. However, due to the food supplementation, significant concentration can raise up in the intestine, where P-gp is abundantly expressed. As many drugs are orally taken, simultaneous administration might affect the concentration of these drugs in the blood. Here, we found that anthocyanidins (aglycons) but not anthocyanins (glycosides) can significantly inhibit P-gp up to 60% of positive control, verapamil. This inhibitory activity was observed for 500 μ m concentrations of malvidin and pelargonidin. We conclude that these compounds may be the source of food-drug interactions either for orally taken drugs or for intravenously administered drugs eliminated via biliary excretion which are the substrates of P-gp. [ABSTRACT FROM AUTHOR]

Delphinidin (Del) is a major anthocyanin that is widely found in pigmented fruits and vegetables. Herein, we investigated the antiadipogenic effect and the molecular mechanism by which Del affects 3T3-L1 preadipocyte differentiation. We found that Del effectively reduced intracellular lipid accumulation and promoted lipolysis while regulating the expression of adipogenic transcription factors and their target genes. This lipid lowering effect of Del was largely limited to the early phase of adipogenesis, which is governed by the delayed cell cycle progression due to G1 cell cycle arrest. Subsequently, Del suppressed the expression of early adipogenic transcription factors, such as C/EBPβ and C/EBPδ, as well as that of intermediate markers, C/EBPα, PPARγ, and the PPARγ-target adipocyte markers adiponectin and aP2 (FABP4). Furthermore, Del treatment activated Wnt1, Wnt10b, the Wnt receptor Fzd2, and the coreceptors Lrp5/6, while it inactivated Gsk3β, a member of the β-catenin destruction complex. Moreover, Del treatment stabilized cytoplasmic β-catenin levels and promoted its nuclear translocation, with subsequent activation of the expression of its downstream target genes, c-Myc and cyclin D1. Our findings therefore suggest that Del can effectively inhibit adipogenesis followed by the stabilization of β-catenin during early 3T3-L1 differentiation via inhibition of its destructive complexes and activation of Wnt signaling, and may thus be a promising candidate for the prevention of metabolic diseases, including obesity. © 2016 BioFactors, 42(1):49-59, 2016 [ABSTRACT FROM AUTHOR]

Phenolics, formed via a complex phenylpropanoid pathway, are important defensive agents in plants and are strongly affected by nitrogen (N) fertilization. Proanthocyanidins (PAs) are one possible endpoint of the phenylpropanoid pathway, and anthocyanidin reductase (ANR) represents a key enzyme in PA biosynthesis. In this study, the expression of silver birch (Betula pendula) anthocyanidin reductase BpANR was inhibited using the RNA interference (RNAi) method, in three consequent BpANR RNAi (ANRi birches) lines. The growth, the metabolites of the phenylpropanoid pathway, and the number of resin glands of the ANRi birches were studied when grown at two N levels. ANRi birches showed decreased growth and reduction in PA content, while the accumulation of total phenolics in both stems and leaves increased. Moreover, ANRi birches produced more resin glands than did wild-type (WT) birches. The response of ANRi birches to N depletion varied compared with that of WT birches, and in particular, the concentrations of some phenolics in stems increased in WT birches and decreased in ANRi birches. Because the inhibition of PAs biosynthesis via ANR seriously affected birch growth and resulted in accumulation of the precursors, the native level of PAs in plant tissues is assumed to be the prerequisite for normal plant growth. This draws attention to the real plant developmental importance of PAs in plant tissues. [ABSTRACT FROM AUTHOR]

This study aimed to optimise aqueous extraction conditions for total phenolic compounds ( TPC) from Davidson's plum ( Davidsonia pruriens F. Muell) and to assess the physicochemical and antioxidant properties of the phenolic-enriched extract. The results showed that temperature, time and ratio significantly affected the extraction of TPC. Optimization of extraction conditions was performed using response surface methodology ( RSM) utilising a Box-Behnken design. Optimal extraction conditions were determined to be temperature: 90 °C, extraction time: 30 min and solvent to mass ratio: 20:1 mL g−1. The extracted solid obtained under these conditions had low-moisture content, high water solubility and contained 45 mg GAE g−1 of TPC, 22 mg RUE g−1 of flavonoids, 3.2 mg CAE g−1 of proanthocyanidins, 2 mg CGE g−1 of anthocyanidins and 56 mg ACE g−1 vitamin C. The extract possessed potent antioxidant capacity, but was comparatively lower than those of vitamin E and BHT. Thus, Davidson's plum should be further investigated for its potential health promoting benefits and utilisation in the nutraceutical and food industries. [ABSTRACT FROM AUTHOR]

Radiation-induced lung injury ( RILI) is a potentially fatal and dose-limiting complication of thoracic radiotherapy. This study was to investigate the protective effects of grape seed pro-anthocyanidins ( GSPs), an efficient antioxidant and anti-carcinogenic agent, on RILI. In our study, it was demonstrated that acute and late RILI was ameliorated after GSPs treatment possibly through suppressing TGF-β1/Smad3/Snail signalling pathway and modulating the levels of cytokines (interferon-γ, IL-4 and IL-13) derived from Th1/Th2 cells. In addition, a sustained high level of PGE2 was also maintained by GSPs treatment to limited fibroblast functions. As shown by electron spin resonance spectrometry, GSPs could scavenge hydroxyl radical (• OH) in a dose-dependent manner, which might account for the mitigation of lipid peroxidation and consequent apoptosis of lung cells. In vitro, GSPs radiosensitized lung cancer cell A549 while mitigating radiation injury on normal alveolar epithelial cell RLE-6 TN. In conclusion, the results showed that GSPs protects mice from RILI through scavenging free radicals and modulating RILI-associated cytokines, suggesting GSPs as a novel protective agent in RILI. [ABSTRACT FROM AUTHOR]

Flavonoids are secondary metabolites with multiple functions. In grape ( Vitis vinifera), the most abundant flavonoids are proanthocyanidins ( PAs), major quality determinants for fruit and wine. However, knowledge about the regulation of PA composition is sparse. Thus, we aimed to identify novel genomic regions involved in this mechanism., Expression quantitative trait locus (e QTL) mapping was performed on the transcript abundance of five downstream PA synthesis genes (dihydroflavonol reductase ( Vv DFR), leucoanthocyanidin dioxygenase ( Vv LDOX), leucoanthocyanidin reductase ( Vv LAR1), Vv LAR2 and anthocyanidin reductase ( Vv ANR)) measured by real-time quantitative PCR on a pseudo F1 population in two growing seasons., Twenty-one e QTLs were identified; 17 of them did not overlap with known candidate transcription factors or cis-regulatory sequences. These novel loci and the presence of digenic epistasis support the previous hypothesis of a polygenic regulatory mechanism for PA biosynthesis., In a genomic region co-locating e QTLs for Vv DFR, Vv LDOX and Vv LAR1, gene annotation and a transcriptomic survey suggested that Vv MYBC2- L1, a gene coding for an R2 R3- MYB protein, is involved in regulating PA synthesis. Phylogenetic analysis showed its high similarity to characterized negative MYB factors. Its spatiotemporal expression profile in grape coincided with PA synthesis. Its functional characterization via overexpression in grapevine hairy roots demonstrated its ability to reduce the amount of PA and to down-regulate expression of PA genes. [ABSTRACT FROM AUTHOR]

Flowers of the butterfly pea ( Clitoria ternatea) accumulate a group of polyacylated anthocyanins, named ternatins, in their petals. The first step in ternatin biosynthesis is the transfer of glucose from UDP-glucose to anthocyanidins such as delphinidin, a reaction catalyzed in C. ternatea by UDP-glucose:anthocyanidin 3- O-glucosyltransferase ( Ct3GT-A; AB185904). To elucidate the structure-function relationship of Ct3GT-A, recombinant Ct3GT-A was expressed in Escherichia coli and its tertiary structure was determined to 1.85 Å resolution by using X-ray crystallography. The structure of Ct3GT-A shows a common folding topology, the GT-B fold, comprised of two Rossmann-like β/α/β domains and a cleft located between the N- and C-domains containing two cavities that are used as binding sites for the donor (UDP-Glc) and acceptor substrates. By comparing the structure of Ct3GT-A with that of the flavonoid glycosyltransferase VvGT1 from red grape ( Vitis vinifera) in complex with UDP-2-deoxy-2-fluoro glucose and kaempferol, locations of the catalytic His-Asp dyad and the residues involved in recognizing UDP-2-deoxy-2-fluoro glucose were essentially identical in Ct3GT-A, but certain residues of VvGT1 involved in binding kaempferol were found to be substituted in Ct3GT-A. These findings are important for understanding the differentiation of acceptor-substrate recognition in these two enzymes. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction (SFE) coupled with high-speed counter-current chromatography (HSCCC) was successfully used for the extraction and on-line isolation of the anthocyanidins from the petals of Chaenomeles sinensi s in two stages. The SFE parameters were optimized by an orthogonal test, and the solvent systems of SFE and HSCCC were calculated and optimized with the help of a multiexponential function model. In the first stage, the lower phase of the solvent system of n-butanol/ tert-butyl methyl ether/acetonitrile/0.1% aqueous TFA (0.715:1.0:0.134:1.592, v/v/v/v) was used as both the SFE modifier and the HSCCC stationary phase, after extraction, the extractants were pumped into HSCCC column, and then eluted with the corresponding upper phase to isolate the moderately hydrophobic compounds. In the second stage, the upper phase of the solvent system of n-butanol/ethyl acetate/acetonitrile/0.1% aqueous TFA (1.348:1.0:0.605:2.156, v/v/v/v) was used as both the SFE modifier and the HSCCC stationary phase, followed by elution with the corresponding lower phase to separate the hydrophobic compounds. With the help of two-stage SFE/HSCCC, six compounds including delphinidin-3- O-glucoside (Dp3G), cyanidin-3- O-glucoside (Cy3G), peonidin-3- O-glucoside (Pn3G), delphinidin (Dp), peonidin (Pn), and malvidin (Mv) were successfully separated within 300 min. The targeted compounds were identified by UV spectrophotometry, MS, and NMR spectroscopy. This research has opened up great prospects for the industrial application of SFE-HSCCC for the automatic extraction and separation of unstable compounds. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: At present, sorghum, fonio and millet are not placed as important commodities in the North American and European food basket, but their importance as ingredients in multigrain and gluten‐free cereal products is highlighted. Therefore in this study the phenolic profile (evaluated by liquid chromatography/tandem mass spectrometry), total phenolic content (assessed by Folin–Ciocalteu assay) and total antioxidant capacity were measured in three African whole grains, i.e. sorghum (Sorghum bicolor ssp. bicolor), fonio (Digitaria exilis) and pearl millet (Pennisetum glaucum L.), before and after a cooking procedure. RESULTS: After the cooking process, soluble phenolic acids increased significantly in sorghum, whereas bound ones and anthocyanins decreased significantly. In millet the cooking process significantly enhanced soluble phenolic acids without affecting those bound, whereas in fonio a slight but significant decrease in almost all soluble phenolic acids was observed along with a significant increase in bound ones. Finally, the cooking process negatively affected both total phenolic content and total antioxidant capacity. CONCLUSION: This is one of the few reports dealing with the antioxidant compounds of these three African whole grains in which the effect of cooking was also evaluated. The data suggested that, to improve their antioxidant properties, specific cultivars should be selected and the cooking procedures carefully considered. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Foam stability related to pasture bloat from alfalfa pastures might be reduced by introducing a gene that stimulates the accumulation of mono-/polymeric-anthocyanidin. The objective of this study was to determine the foam formation (at 0 min) and stability (at 150 min) from aqueous leaf extracts of three transgenic Lc-alfalfa progeny (Beav Lc1, Ramb Lc3 and Rang Lc4), parental non-transgenic (NT) alfalfa and AC Grazeland (bloat-reduced cultivar) harvested at 07:00 or 18:00 h. Initial and final foam volumes at 07:00 h were lower for AC Grazeland compared with all other treatments and lower for Rang Lc4 compared with the other two Lc-progeny at 0 min and NT-alfalfa at 150 min. At 18:00 h, initial foam volume was larger for NT-alfalfa and final foam volume was larger for Ramb Lc3 compared with AC Grazeland, Beav Lc1 and Rang Lc4. Spectroscopic vibration associated with carbohydrates increased initial foam volume and stability. More amide I relative to amide II, fewer α-helices relative to β-sheets and leaf extract ethanol-film and protein content increased initial foam volume but did not stabilize it. Spectroscopic vibration associated with all carbohydrates other than structural carbohydrates was more important than vibration from protein structures for foam formation and stabilization. In conclusion, Lc-alfalfa accumulated anthocyanidin and had reduced foaming properties compared with parental NT alfalfa but AC Grazeland and Rang Lc4 had the lowest foaming properties. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]

Abstract: We have used Förster resonance energy transfer detected by fluorescence lifetime imaging microscopy (FLIM-FRET) to provide the first evidence from living plants cells for the existence of a flavonoid metabolon. The distribution of flux within this system may be regulated by the direct competition of enzymes that catalyze key branch-point reactions, flavonol synthase 1 and dihydroflavonol 4-reductase, for association with the entry-point enzyme, chalcone synthase. Because the flavonoid enzymes were likely recruited from pathways of primary metabolism, our findings suggest a new general working model for the regulation of dynamic pathways in their native cellular context. Structured summary of protein interactions: CHS and FLS1 physically interact by fluorescence resonance energy transfer (View interaction) CHS and DFR physically interact by fluorescence resonance energy transfer (View Interaction 1, 2) FLS1 physically interacts with CHS and DFR by competition binding (View interaction) [Copyright &y& Elsevier]

The Arabidopsis transparent testa ( tt) mutant tt19-4 shows reduced seed coat colour, but stains darkly with DMACA and accumulates anthocyanins in aerial tissues. Positional cloning showed that tt19-4 was allelic to tt19-1 and has a G-to-T mutation in a conserved 3′-domain in the TT19-4 gene. Soluble and unextractable seed proanthocyanidins and hydrolysis of unextractable proanthocyanidin differ between wild-type Col-4 and both mutants. However, seed quercetins, unextractable proanthocyanidin hydrolysis, and seedling anthocyanin content, and flavonoid gene expression differ between tt19-1 and tt19-4. Transformation of tt19-1 with a TT19-4 cDNA results in vegetative anthocyanins, whereas TT19-4 cDNA cannot complement the proanthocyanidin and pale seed coat phenotype of tt19-1. Both recombinant TT19 and TT19-4 enzymes are functional GSTs and are localized in the cytosol, but TT19 did not function with wide range of flavonoids and natural products to produce conjugation products. We suggest that the dark seed coat of Arabidopsis is related to soluble proanthocyanidin content and that quercetin holds the key to the function of TT19. In addition, TT19 appears to have a 5′ GSH-binding domain influencing both anthocyanin and proanthocyanidin accumulation and a 3′ domain affecting proanthocyanidin accumulation by a single amino acid substitution. [ABSTRACT FROM AUTHOR]

Proanthocyanidins (PAs) are a class of flavonoids with numerous functions in plant ecology and development, including protection against microbial infection, animal foraging and damage by UV light. PAs are also beneficial in the human diet and livestock farming, preventing diseases of the cardiovascular system and lowering the risk of cancer, asthma and diabetes. Apples ( Malus x domestica Borkh.) are naturally rich in flavonoids, but the flavonoid content and composition varies significantly between cultivars. In this work, we applied knowledge from the model plant Arabidopsis thaliana, for which the main features of flavonoid biosynthesis have been elucidated, to investigate PA accumulation in apple. We identified functional homologues of the Multidrug And Toxic compound Extrusion (MATE) gene TRANSPARENT TESTA12 from A. thaliana using a comparative genomics approach. MdMATE1 and MdMATE2 were differentially expressed, and the function of the encoded proteins was verified by complementation of the respective A. thaliana mutant. In addition, MdMATE genes have a different gene structure in comparison to homologues from other species. Based on our findings, we propose that MdMATE1 and MdMATE2 are vacuolar flavonoid/H-antiporters, active in PA accumulating cells of apple fruit. The identification of these flavonoid transporter genes expands our understanding of secondary metabolite biosynthesis and transport in apple, and is a prerequisite to improve the nutritional value of apples and apple-derived beverages. [ABSTRACT FROM AUTHOR]

1. Isoliquiritigenin (ISL) is a simple chalcone-type flavonoid derived from liquorice compounds. It has been reported to have anti-oxidative and antitumour activities. The aim of the present study was to investigate the antitumour effect of ISL on prostate cancer cells and to explore the possible signalling mechanisms involved. 2. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The fluorescent probe 2′,7′-dichlorofluorescein diacetate (H2DCF-DA) was used to measure intracellular levels of reactive oxygen species (ROS). Mitochondrial membrane potential (Ψm) was measured using the mitochondrial probe 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-benzimidazolylcarbocyanine iodide (JC-1). 3. Isoliquiritigenin treatment (10–100 μmol/L for 24 h) markedly inhibited the proliferation of both C4-2 and LNCaP prostate cancer cells in a dose-dependent manner. Intriguingly, ISL treatment (10–100 μmol/L for 24 h) had no effect on the viability of IEC-6 normal epithelial cells. Treatment of C4-2 and IEC-6 cells with 87.0 μmol/L ISL significantly decreased ROS levels and the Ψm of C4-2 cells, but had no effect on either parameter in IEC-6 cells. Furthermore, AMP-activated protein kinase (AMPK) and extracellular-signal regulated kinase (ERK) levels were three to fourfold higher in IEC-6 cells than in C4-2 cells ( P < 0.05). 4. The results of the present study suggest that ISL, a natural anti-oxidant, selectively inhibits the proliferation of prostate cancer C4-2 cells, which may be attributed, in part, to defective AMPK and ERK signalling pathways in C4-2 compared with IEC-6 cells. [ABSTRACT FROM AUTHOR]

Background and Purpose: Dietary anthocyanins hold great promise in the prevention of chronic disease but factors affecting their bioavailability remain poorly defined. Specifically, the role played by transport mechanisms at the intestinal and blood-brain barriers (BBB) is currently unknown.Experimental Approach: In the present study, 16 anthocyanins and anthocyanidins were exposed to the human efflux transporters multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP), using dye efflux, ATPase and, for BCRP, vesicular transport assays.Key Results: All test compounds interacted with the BCRP transporter in vitro. Of these, seven emerged as potential BCRP substrates (malvidin, petunidin, malvidin-3-galactoside, malvidin-3,5-diglucoside, cyanidin-3-galactoside, peonidin-3-glucoside, cyanidin-3-glucoside) and 12 as potential inhibitors of BCRP (cyanidin, peonidin, cyanidin-3,5-diglucoside, malvidin, pelargonidin, delphinidin, petunidin, delphinidin-3-glucoside, cyanidin-3-rutinoside, malvidin-3-glucoside, pelargonidin-3,5-diglucoside, malvidin-3-galactoside). Malvidin, malvidin-3-galactoside and petunidin exhibited bimodal activities serving as BCRP substrates at low concentrations and, at higher concentrations, as BCRP inhibitors. Effects on MDR1, in contrast, were weak. Only aglycones exerted mild inhibitory activity.Conclusions and Implications: Although the anthocyanidins under study may alter pharmacokinetics of drugs that are BCRP substrates, they are less likely to interfere with activities of MDR1 substrates. The present data suggest that several anthocyanins and anthocyanidins may be actively transported out of intestinal tissues and endothelia, limiting their bioavailability in plasma and brain. [ABSTRACT FROM AUTHOR]

We quantified the metabolic cost to the Antarctic leafy liverwort Cephaloziella varians of responding to an abrupt increase in ultraviolet B (UVB) radiation exposure in the natural environment at Rothera Point on the western Antarctic Peninsula (67 °34′S, 68 °07′W). The liverwort was protected from exposure to UVB radiation for 44 days with screens containing Mylar polyester, after which time its thalli, which are normally black in colour, had become green owing to reduced concentrations of an anthocyanidin, identified here as riccionidin A, in thallus tips. Thalli were then exposed to an abrupt increase in UVB radiation by removing the screens. The thalli became visibly darker within 48 h of the screens being removed, resynthesizing riccionidin A to the same concentration as that present in thalli outside screens during this period. Chlorophyll fluorescence measurements indicated that nonphotochemical quenching was higher in the thalli formerly under the screens than in those not previously covered with screens, but that Fv/ Fm and photochemical quenching were the same in the two groups of thalli. We used data from aqueous phase oxygen electrode measurements to calculate an estimate for carbon fixation by C. varians during the 48 h after the screens were removed. Assuming a photosynthetic quotient for Antarctic bryophytes of 1, these analyses indicated that the minimum weight of carbon used to synthesize riccionidin A was equivalent to 1.85% of the carbon fixed by thalli during the 48 h after the abrupt increase in UVB radiation exposure. [ABSTRACT FROM AUTHOR]

Together with leucoanthocyanidin reductase, anthocyanidin reductase (ANR) is one of the two enzymes of the flavonoid-biosynthesis pathway that produces the flavan-3-ol monomers required for the formation of proanthocyanidins or condensed tannins. It has been shown to catalyse the double reduction of anthocyanidins to form 2R,3R-flavan-3-ols, which can further transformed to the 2S,3R isomers by non-enzymatic epimerization. ANR from grape (Vitis vinifera) was expressed in Escherichia coli and purified. Unexpectedly, RP-HPLC, LC-MS and NMR experiments clearly established that the enzyme produces a 50:50 mixture of 2,3-cis and 2,3-trans flavan-3-ols which have been identified by chiral chromatography to be 2S,3S- and 2S,3R-flavan-3-ols, i.e. the naturally rare (+)-epicatechin and (-)-catechin, when cyanidin is used as the substrate of the reaction. The first three-dimensional structure of ANR is described at a resolution of 2.2 &Aring' and explains the inactivity of the enzyme in the presence of high salt concentrations. [ABSTRACT FROM AUTHOR]

MYB transcription factors help to control anthocyanin biosynthesis in plants, and ectopic expression of the Arabidopsis Production of Anthocyanin Pigment 1 (PAP1) transcription factor activates the anthocyanin pathway in tobacco, suggesting the general utility of such factors for metabolic engineering of anthocyanins and anthocyanin-derived compounds such as proanthocyanidins (condensed tannins). However, PAP1 does not activate anthocyanin biosynthesis in the model legume Medicago truncatula or in alfalfa ( Medicago sativa). A related Legume Anthocyanin Production 1 ( LAP1) gene was identified from the genome of M. truncatula. When constitutively expressed in transgenic alfalfa, M. truncatula or white clover, LAP1 induced massive accumulation of anthocyanin pigments comprising multiple glycosidic conjugates of cyanidin. Oligomeric/polymeric compounds with some diagnostic characteristics of proanthocyanidins also accumulated in LAP1-expressing plants, but these compounds were not composed of (epi)catechin units. Over 260 and 70 genes were up-regulated in leaves of alfalfa or M. truncatula, respectively , in response to constitutive expression of LAP1, many of which are involved in anthocyanin biosynthesis. In particular, the glucosyltransferase UGT78G1, previously identified as showing preference for isoflavonoid substrates in vitro, was strongly up-regulated by LAP1, and appears to function as an anthocyanin glycosyltransferase in vivo. Over-expression of UGT78G1 in transgenic alfalfa resulted in increased anthocyanin accumulation when plants were exposed to abiotic stress. [ABSTRACT FROM AUTHOR]

Luteolin (3′,4′,5,7-tetrahydroxyflavone), a flavonoid, has been known to possess antimutagenic, antitumorigenic, antioxidant, and anti-inflammatory properties. In this study, we investigated the role of luteolin in the regulation of adipogenic differentiation in 3T3-L1 preadipocytes. Luteolin inhibited intracellular triglyceride accumulation in a dose-dependent manner without cytotoxicity. Western blot and reverse transcription-polymerase chain reaction analyses showed that this inhibition was accompanied by attenuated expression of the adipogenic transcription factors: peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α. Luteolin inhibited the PPARγ transactivation stimulated by rosiglitazone, a synthetic agonist, in COS-7 cells and inhibited rosiglitazone-induced adipogenic differentiation in 3T3-L1 cells. These data suggest that luteolin exerts antiadipogenic effects by suppressing adipogenic transcription factors and by inhibiting the transactivation of PPARγ. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Flavonoids exhibit a variety of beneficial effects in cardiovascular diseases. Although their therapeutic properties have been attributed mainly to their antioxidant action, they have additional protective mechanisms such as inhibition of signal transducer and activator of transcription 1 (STAT1) activation. Here, we have investigated the cardioprotective mechanisms of strong antioxidant flavonoids such as quercetin, myricetin and delphinidin. Although all of them protect the heart from ischemia/reperfusion-injury, myricetin and delphinidin exert a more pronounced protective action than quercetin by their capacity to inhibit STAT1 activation. Biochemical and computer modeling analysis indicated the direct interaction between STAT1 and flavonoids with anti-STAT1 activity. [Copyright &y& Elsevier]

Antidesma thwaitesianum Müll. Arg. or mao is widely used as commercial products of juice and wine in Thailand. As a result, waste products from the mao plant, such as mao seeds (MS) and mao marcs (MM), are plentiful. We aimed to purify and analyze polyphenolic content in both MS and MM and to investigate the radical scavenging activities of these polyphenolics against 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2′-Azinobis (3-ethylbenzothiazoline 6-sulphonate) (ABTS) radicals and thiobarbituric acid reactive products (TBARP). The results showed MS and MM to be an abundant source of polyphenols (97.32 to 130 mg gallic acid equivalents [GAE]/g) and proanthocyanidins. The radical scavenging activities of MS/MM against DPPH and ABTS radicals (IC50 of 0.85 to 1.21 μg/mL) were significantly higher ( P < 0.05) than that of standard trolox (IC50 of 5.05 μg/mL). Activity of MS/MM extracts were 3.74 and 3.80 μg/mL trolox eq/g f.w. for the DPPH and ABTS assays, respectively. The oxidation of erythrocyte membranes using 2-thiobarbituric acid demonstrated that the protective effect of MS/MM on lipid peroxidation is as strong as grape seed proanthocyanidin extract. These findings suggest that polyphenolic compounds and proanthocyanidins isolated from these mao extracts had much higher antioxidant activities than those of standard trolox and exhibited similar antioxidant potential to grape seed proanthocyanidin extract. These findings may also increase value of mao waste products and allow development of commercial health products. [ABSTRACT FROM AUTHOR]

Fruit and vegetable intake is typically low for type 2 diabetics, possibly due to a perceived adverse effect on glycemic control. Cranberry juice (CBJ) may represent an attractive means for increasing fruit intake and simultaneously affording positive health benefits. This single cross-over design compared metabolic responses of type 2 diabetics ( n= 12) to unsweetened low-calorie CBJ (LCCBJ; 19 Cal/240 mL), carbohydrate sweetened normal calorie CBJ (NCCBJ; 120 Cal/240 mL), isocaloric low-calorie sugar water control (LCC), and isocaloric normal calorie sugar water control (NCC) interventions. CBJ flavonols and anthocyanins, and proanthocyanidins were quantified with HPLC, LC-MS, and MALDI-TOF that includes an original characterization of several large oligomeric proanthocyanidins. Blood glucose peaked 30 min postingestion after NCCBJ and NCC at 13.3 ± 0.5 and 12.8 ± 0.9 (mmol/L), and these responses were significantly greater than the LCCBJ and LCC peaks of 8.1 ± 0.5 and 8.7 ± 0.5, respectively. Differences in glycemic response remained significant 60 min, but not 120 min postingestion. Plasma insulin values 60 min postingestion for NCCBJ and NCC interventions were 140 ± 19 and 151 ± 18 (pmol/L), respectively, and significantly greater than the LCCBJ and LCC values of 56 ± 10 and 54 ± 10; differences were not significant 120 min postingestion. Metabolic responses within the 2 high and 2 low-calorie beverages were virtually identical; however, exposure to potentially beneficial nutrients was greater with CBJ. Relative to conventionally sweetened preparation, LCCBJ provides a favorable metabolic response and should be useful for promoting increased fruit consumption among type 2 diabetics or others wishing to limit carbohydrate intake. [ABSTRACT FROM AUTHOR]

The flip regression procedure that we used earlier for handling xanthones (J Enzyme Inhib Med Chem;22:277, 2006) has been applied to flavonoid analogues. It is demonstrated that the electrostatic and quantum chemical descriptors for the interaction of flavonoids with the specific enzymatic active site plays an important role. In particular, the maximal total interaction for a C–O bond is the most important factor in the regression. In this contribution it is shown that the orientation of nodes in their occupied π orbitals, and also the energies of these orbitals explain a further large portion of the variance in their inhibitory activity. [ABSTRACT FROM AUTHOR]

Abstract: The major anthocyanin in A. thaliana is a cyanidin derivative modified by glycosylation as well as by the addition of three acyl moieties: malonyl, p-coumaroyl, and sinapoyl. We have isolated a member of the BAHD acyltransferase family which catalyzes this malonylation reaction by combining a reverse genetics approach with biochemical genomics. A mutant line containing a T-DNA insertion in At3g29590, the gene encoding the malonylating enzyme, is incapable of producing malonylated anthocyanins. Transgenic plants harboring an RNAi silencing cassette for At3g29590 demonstrate a positive correlation between reduction in the At3g29590 gene transcript and the decrease of malonylated anthocyanins. Transcript levels for both At3g29590 and the epistatic gene At4g14090, encoding 5-O-anthocyanin glucosyltransferase, increase in several plant lines as they accumulate anthocyanin pigments. Investigation of the heterologously expressed and purified malonylating enzyme showed that the activity is specific for malonyl-CoA and for anthocyanins with 5-O-glucosylation. The malonyl transfer itself occurs only to the 5-O-glucoside function, and not to any of the other sugar moieties present in A. thaliana anthocyanins. Hence, both in vivo and in vitro results define the activity of the At3g29590-encoded enzyme as an anthocyanin 5-O-glucoside-6″-O-malonyltransferase (At5MAT). [Copyright &y& Elsevier]

Different colors, such as purple, brown, red and white, occur in the pericarp of rice. Here, two genes affecting proanthocyanidin synthesis in red- and brown-colored rice were elucidated. Genetic segregation analysis suggested that the Rd and A loci are identical, and both encode dihydroflavonol-4-reductase (DFR). The introduction of the DFR gene into an Rcrd mutant resulted in red-colored rice, which was brown in the original mutant, demonstrating that the Rd locus encodes the DFR protein. Accumulation of proanthocyanidins was observed in the transformants by the introduction of the Rd gene into the rice Rcrd line. Protein blot analysis showed that the DFR gene was translated in seeds with alternative translation initiation. A search for the Rc gene, which encodes a transacting regulatory factor, was conducted using available DNA markers and the Rice Genome Automated Annotation System program. Three candidate genes were identified and cloned from a rice RcRd line and subsequently introduced into a rice rcrd line. Brown-colored seeds were obtained from transgenic plants by the introduction of a gene containing the basic helix–loop–helix (bHLH) motif, demonstrating that the Rc gene encodes a bHLH protein. Comparison of the Rc locus among rice accessions showed that a 14-bp deletion occurred only in the rc locus. [ABSTRACT FROM AUTHOR]

The control of TT8 expression was investigated in this study, and it was demonstrated that it constitutes a major regulatory step in the specific activation of the expression of flavonoid structural genes. First, the GUS activity generated in planta from a TT8::uidA construct revealed cell-specific activation of the TT8 promoter consistent with the known involvement of the TT8 bHLH factor in proanthocyanidin, anthocyanin and mucilage biosynthesis. Moreover, the activity of this reporter construct was strongly affected in ttg1, TT2 overexpressers (OE), and PAP1-OE, suggesting interplay between TT2, PAP1, TTG1 and the activation of the TT8 promoter in planta. To further investigate the mechanisms involved, we used 35S::TT2-GR and 35S::TTG1-GR transgenic plants (expressing fusion proteins with the glucocorticoid receptor), as well as one-hybrid experiments, to determine the direct effect of these factors on TT8 expression. Interestingly, in vivo binding of TT2 and PAP1 to the TT8 promoter was dependent on the simultaneous expression of TT8 or the homologous bHLH factors GL3 and EGL3. Consistent with these results, the activity of the TT8::uidA reporter was strongly affected in the seed endothelium of a tt8 mutant. Similarly, a strong decrease in the level of TT8 mRNA was detected in the siliques of a gl3 × egl3 mutant and in plants that express a dominant negative form of the PAP1 protein, suggesting that TT8 expression is controlled by different combinations of MYB and bHLH factors in planta. The importance of this positive feedback mechanism in the strong and specific induction of proanthocyanidin biosynthesis in the seed coat of Arabidopsis thaliana is discussed. [ABSTRACT FROM AUTHOR]

Interdisciplinary research endeavors are directed at understanding the molecular mechanisms of neurodegenerative and chronic diseases that affect human lifestyle. Hence the potential for developing medicinal herb-derived and food plant-derived prophylactic agents directed at neurological, metabolic, cardiovascular and psychiatric disorders abounds. Oligonol is a novel technology product emanating from the oligomerization of polyphenols, typically proanthocyanidin from a variety of fruits (grapes, apples, persimmons etc.) that has optimized bioavailability. It is an optimized phenolic product containing catechin-type monomers and oligomeric proanthocyanidins, the easily absorbed forms. Typically the constituents of Oligonol are 15–20% monomers, 8–12% dimers and 5–10% trimers. Supplementation of mice with Oligonol prior to the administration of ferric-nitrilotriacetic complex (a Fenton chemistry model) significantly reduced the extent of lipid peroxidation in the kidney, brain and liver. Oligonol triggers apoptosis in the MCF-7 and MDA-MB-231 breast cancer cells through modulation of the pro-apoptotic Bcl-2 family of proteins and the MEK/ERK signaling pathway, an observation suggesting its important chemopreventive effects. The senescence-accelerated strain of mice (SAM) are models of senescence acceleration and geriatric disorders which exhibit learning and memory deficits and enhanced production or defective control of oxidative stress leading. [ABSTRACT FROM AUTHOR]

Proanthocyanidins (PAs) and their monomeric building blocks, the (epi)-flavan-3-ols, are plant antioxidants that confer multiple human health benefits. The presence of PAs in forage crops is an important agronomic trait, preventing pasture bloat in ruminant animals. However, many consumed plant materials lack PAs, and there has been little success to date in introducing monomeric or polymeric flavan-3-ols de novo into plant tissues for disease prevention by dietary means or development of ‘bloat-safe’ forages. We report the introduction of PAs into plants by combined expression of a MYB family transcription factor and anthocyanidin reductase for conversion of anthocyanidin into (epi)-flavan-3-ol. Tobacco leaves expressing both transgenes accumulated epicatechin and gallocatechin monomers, and a series of dimers and oligomers consisting primarily of epicatechin units. The levels of PAs reached values that would confer bloat reduction in forage species. Expression of anthocyanidin reductase in anthocyanin-containing leaves of the forage legume Medicago truncatula resulted in production of a specific subset of PA oligomers. [ABSTRACT FROM AUTHOR]

Abstract: Anthocyanidins were proposed to derive from (+)-naringenin via (2R,3R)-dihydroflavonol(s) and (2R,3S,4S)-leucocyanidin(s) which are eventually oxidized by anthocyanidin synthase (ANS). Recently, the role of ANS has been put into question, because the recombinant enzyme from Arabidopsis exhibited primarily flavonol synthase (FLS) activity with negligible ANS activity. This and other studies led to the proposal that ANS as well as FLS may select for dihydroflavonoid substrates carrying a “β-face” C-3 hydroxyl group and initially form the 3-geminal diol by “α-face” hydroxylation. Assays with recombinant ANS from Gerbera hybrida fully supported the proposal and were extended to catechin and epicatechin isomers as potential substrates to delineate the enzyme specificity. Gerbera ANS converted (+)-catechin to two major and one minor product, whereas ent(−)-catechin (2S,3R-trans-catechin), (−)-epicatechin, ent(+)-epicatechin (2S,3S-cis-epicatechin) and (−)-gallocatechin were not accepted. The K m value for (+)-catechin was determined at 175μM, and the products were identified by LC–MSn and NMR as the 4,4-dimer of oxidized (+)-catechin (93%), cyanidin (7%) and quercetin (trace). When these incubations were repeated in the presence of UDP-glucose:flavonoid 3-O-glucosyltransferase from Fragaria × ananassa (FaGT1), the product ratio shifted to cyanidin 3-O-glucoside (60%), cyanidin (14%) and dimeric oxidized (+)-catechin (26%) at an overall equivalent rate of conversion. The data appear to identify (+)-catechin as another substrate of ANS in vivo and shed new light on the mechanism of its catalysis. Moreover, the enzymatic dimerization of catechin monomers is reported for the first time suggesting a role for ANS beyond the oxidation of leucocyanidins. [Copyright &y& Elsevier]