Sunlight radiation is a main environmental factor which affects anthocyanin synthesis. To clarify the regulatory mechanism of sunlight on the synthesis of anthocyanin in apple peel, bagged apples ...were exposed to diverse intensities of sunlight through different shading treatments. Under an increased solar ultraviolet-B (UV-B) light intensity, the concentration of anthocyanin in apple peels was consistent with the Michaelis-Menten equation. Under lower sunlight intensities, diphenyleneiodonium chloride (DPI, an inhibitor of plasma membrane NAD(P)H oxidase) treatment increased both the concentration of cyanidin-3-glycoside and the activity of dihydroflavonol 4-reductase (DFR). However, under higher sunlight intensities, DPI treatment decreased the concentrations of cyanidin-3-glycoside and quercetin-3-glycoside, as well as the activities of DFR and UDP-glycose: flavonoid 3-O-glycosyltransferase (UFGT). These results indicate that, under low sunlight intensity, anthocyanin synthesis in apple peel was limited by the supply of the substrate cyanidin, which was regulated by the DFR activity. Nevertheless, after exposure to high sunlight intensity, the anthocyanin produced in the apple peel was dependent on UFGT activity.
Zoysiagrass (Zoysia japonica Steud.) is commonly found in temperate climate regions and widely used for lawns, in part, owing to its uniform green color. However, some zoysiagrass cultivars ...accumulate red to purple pigments in their spike and stolon tissues, thereby decreasing the aesthetic value. Here we analyzed the anthocyanin contents of two zoysiagrass cultivars 'Anyang-jungji' (AJ) and 'Greenzoa' (GZ) that produce spikes and stolons with purple and green colors, respectively, and revealed that cyanidin and petunidin were primarily accumulated in the pigmented tissues. In parallel, we performed a de novo transcriptome assembly and identified differentially expressed genes between the two cultivars. We found that two anthocyanin biosynthesis genes encoding anthocyanidin synthase (ANS) and dihydroflavonol 4-reductase (DFR) were preferentially upregulated in the purple AJ spike upon pigmentation. Both ANS and DFR genes were also highly expressed in other zoysiagrass cultivars with purple spikes and stolons, but their expression levels were significantly low in the cultivars with green tissues. We observed that recombinant ZjDFR1 and ZjANS1 proteins successfully catalyze the conversions of dihydroflavonols into leucoanthocyanidins and leucoanthocyanidins into anthocyanidins, respectively. These findings strongly suggest that upregulation of ANS and DFR is responsible for tissue-specific anthocyanin biosynthesis and differential pigmentation in zoysiagrass. The present study also demonstrates the feasibility of a de novo transcriptome analysis to identify the key genes associated with specific traits, even in the absence of reference genome information.
Using RNA-seq, this study analysed an apple (Malus×domestica) anthocyanin-deficient yellow-skin somatic mutant ‘Blondee’ (BLO) and its red-skin parent ‘Kidd’s D-8’ (KID), the original name of ‘Gala’, ...to understand the molecular mechanisms underlying the mutation. A total of 3299 differentially expressed genes (DEGs) were identified between BLO and KID at four developmental stages and/or between two adjacent stages within BLO and/or KID. A weighted gene co-expression network analysis (WGCNA) of the DEGs uncovered a network module of 34 genes highly correlated (r=0.95, P=9.0 × 10−13) with anthocyanin contents. Although 12 of the 34 genes in the WGCNA module were characterized and known of roles in anthocyanin, the remainder 22 appear to be novel. Examining the expression of ten representative genes in the module in 14 diverse apples revealed that at least eight were significantly correlated with anthocyanin variation. MdMYB10 (MDP0000259614) and MdGST (MDP0000252292) were among the most suppressed module member genes in BLO despite being undistinguishable in their corresponding sequences between BLO and KID. Methylation assay of MdMYB10 and MdGST in fruit skin revealed that two regions (MR3 and MR7) in the MdMYB10 promoter exhibited remarkable differences between BLO and KID. In particular, methylation was high and progressively increased alongside fruit development in BLO while was correspondingly low and constant in KID. The methylation levels in both MR3 and MR7 were negatively correlated with anthocyanin content as well as the expression of MdMYB10 and MdGST. Clearly, the collective repression of the 34 genes explains the loss-of-colour in BLO while the methylation in MdMYB10 promoter is likely causal for the mutation.
Blue light photoreceptor cryptochrome 1 (CRY1) in herbaceous plants plays crucial roles in various developmental processes, including cotyledon expansion, hypocotyl elongation and anthocyanin ...biosynthesis. However, the function of CRY1 in perennial trees is unclear. In this study, we identified two ortholog genes of CRY1 (PagCRY1a and PagCRY1b) from Populus, which displayed high sequence similarity to Arabidopsis CRY1. Overexpression of PagCRY1 substantially inhibited plant growth and promoted secondary xylem development in Populus, while CRISPR/Cas9‐mediated knockout of PagCRY1 enhanced plant growth and delayed secondary xylem development. Moreover, overexpression of PagCRY1 dramatically increased anthocyanin accumulation. The further analysis supported that PagCRY1 functions specifically in response to blue light. Taken together, our results demonstrated that modulating the expression of blue light photoreceptor CRY1 ortholog gene in Populus could significantly influence plant biomass production and the process of wood formation, laying a foundation for further investigating the light‐regulated tree growth.
Summary statement
Light is one of the most important environmental signals that govern plant growth and development. This study demonstrated that the blue light photoreceptor PagCRY1 substantially promotes wood formation and anthocyanin biosynthesis in Populus, and provides evidence showing that HY5 and BBX6 may act downstream of PagCRY1 to activate lignin and anthocyanin biosynthesis.
Anthocyanins are increasingly valued in the food industry for their functional properties and as food colorants. The broadness of their applications has, however, been limited by the lack of ...stability of these natural pigment extracts in a number of food systems. The potential application of pyranoanthocyanins, anthocyanin derivatives with better stability conferred by the added pyran ring, as a food ingredient was determined. Methylpyranoanthocyanin (MPA) was prepared from reaction of acetone and anthocyanin extracts from red grapes. Reaction products were sequentially purified with polyamide resin, TSK gel resin and semi-preparative HPLC to a purity level >98%. Cytoprotective influence tests of the purified MPA indicated its significant protective effect against H2O2 induced MRC-5 cell damage. Results of evaluations of possible acute toxicity effects on MPA-fed mice, including macro and microscopic assessments, support the conclusion of a non-toxic effect of MPA, and its potential safe use as a food additive.
•Methyl pyranoanthocyanin was synthesized from acetone and red grape skin extracts.•Methyl pyranoanthocyanin shows significant protective effect on MRC-5 cell.•Methyl pyranoanthocyanin is a non-toxic, potential food additive.
The metabolic fate of dietary anthocyanins (ACN) has not been fully clarified in humans. In all previous studies, the proportion of total ACN absorbed and excreted in urine was <1% intake. This study ...aimed to elucidate the human metabolism of cyanidin-glucosides (CyG) contained in blood orange juice (BOJ). One liter of BOJ, containing 71 mg CyG, was consumed by 6 healthy, fasting volunteers. Blood, urine, and fecal samples were collected at baseline and at different times up to 24 h after juice consumption. The content of native CyG, glucuronidated/methylated derivatives, and various phenolic acids was determined by HPLC/MS/MS. The serum maximal concentration of cyanidin-3-glucoside (Cy-3-glc) was 1.9 ± 0.6 nmol/L and that of protocatechuic acid (PCA) was 492 ± 62 nmol/L at 0.5 h and 2 h after juice consumption, respectively. The calculated total amounts in plasma corresponded for Cy-3-glc to 0.02% and for PCA to 44% of CyG ingested. CyG and glucuronidated/methylated metabolites, but not PCA, were detected in urine. ACN recovered in 24-h urine collections represented ~1.2% of the ingested dose. Both CyG (1.90 ± 0.04 nmol/g) and PCA (277 ± 0.2 nmol/g) were recovered in 24-h fecal samples. Data explained the metabolic fate of 74% of BOJ ACN. PCA was for the first time, to our knowledge, identified in humans as a CyG metabolite, accounting for almost 73% of ingested CyG. A high concentration of PCA may explain the short-term increased plasma antioxidant activity observed after intake of cyanidin-rich food and it can also contribute to the numerous health benefits attributed to dietary ACN consumption.
Grape skins produced during the grape juice production and processing contain abundant anthocyanins and other active compounds. Consequently, this study optimized the extraction conditions for ...ultrasound‐assisted enzymatic extraction (UAEE) of anthocyanins from grape skins via response surface methodology coupled with genetic algorithm. The optimum extraction parameters to achieve the highest anthocyanins yield (3.01 ± 0.04) mg/g from grape skins by UAEE were obtained under an extraction temperature of 50 °C, ultrasonic power of 400 W, pectinase dosage of 0.16%, and extraction time of 28 min. The AB‐8 macroporous resin combined Sephadex LH‐20 techniques were further employed to purify the anthocyanins extracts obtained under optimum extraction conditions (AEOEC), and the main anthocyanins were identified using high‐performance liquid chromatography tandem mass spectrometry. The purified anthocyanins contained two anthocyanins in terms of delphinidin‐3,5‐O‐diglucoside and cyanidin‐3‐O‐rutinoside with purity of 91.35% and 92.64%, respectively. Ultimately, we further evaluated the antitumor activity of AEOEC and two purified anthocyanins on breast cancer. The results indicated that the antitumor effect of AEOEC on breast cancer MCF‐7 cells was better than that of two purified anthocyanins. In addition, AEOEC could memorably increase intracellular reactive oxygen species levels and apoptosis of MCF‐7 cells, and arrest MCF‐7 cells in the G2/M phases. The findings provide an effective and feasible method for anthocyanins extraction and reduce the environmental burden of this waste.
Abstract
Context
Anthocyanins are phenolic compounds found in berries. They exhibit promising health benefits in humans, but no accurate biomarkers of berry intake have been identified thus far.
...Objective
The aim of this systematic review is to propose a biomarker of anthocyanin-rich berry intake in human plasma and urine.
Data Sources
PubMed and Cochrane databases were searched from January 2008 to January 2019.
Study Selection
Databases were searched for human intervention studies that assessed the presence of anthocyanins in human body fluids using high-throughput techniques. Non-English articles and studies publishing targeted analyses were excluded.
Data Extraction
Ten clinical trials, in which 203 phenolic compounds were identified, were included and assessed qualitatively. The following criteria were used to identify biomarkers of berry intake: frequency, plausibility, dose-response, time response, robustness, reliability, stability, analytical performance, and reproducibility. Sensitivity and specificity of potential biomarkers were determined by the receiver operating characteristic curve.
Results
Of the 203 phenolic compounds identified in human samples, the anthocyanin cyanidin-3-glucoside was the molecule found most frequently in urine (58.06%) and plasma (69.49%). Cyanidin-3-glucoside fulfills the essential criterion of plausibility as well as the dose-response, time response, stability, and analytical performance criteria. Its positive predictive value is 74% (P = 0.210) in plasma, which is acceptable, and 61.7% (P = 0.402) in urine.
Conclusions
Current evidence suggests that cyanidin-3-glucoside is a potential biomarker of anthocyanin-rich berry intake in plasma and urine of healthy humans.
PROSPERO registration number
CRD42018096796.
•Response surface-optimized preparation of anthocyanin-loaded chitosan nanoparticles.•Box-Behnken design for high encapsulation efficiency and small particle size.•First anthocyanin nanoparticles of ...carboxymethyl chitosan and chitosan hydrochloride.•Chitosan nanoparticles delayed anthocyanin degradation in simulated GI fluid.•Chitosan nanoparticles increased anthocyanin storage stability in a model beverage.
The optimal preparation parameters to create anthocyanin-loaded chitosan nanoparticles was predicted using response surface methodology (RSM). A Box-Behnken design was used to determine the preparation parameters that would achieve the preferred particle size and high encapsulation efficiency. The result suggested that the optimized conditions were 2.86mg/mL carboxymethyl chitosan (CMC), 0.98mg/mL chitosan hydrochloride (CHC) and 5.97mg anthocyanins. Using the predicted amounts, the experimentally prepared particles averaged 219.53nm with 63.15% encapsulation efficiency. The result was less than 5% different than the predicted result of 214.83nm particle size and 61.80% encapsulation efficiency. Compared with the free anthocyanin solution, the anthocyanin-loaded chitosan nanoparticles showed a slowed degradation in simulated gastrointestinal fluid. Compared with the free anthocyanin solutions in a model beverage system, the stability of the anthocyanins was increased in the anthocyanin-loaded chitosan nanoparticles.
The anthocyanin synthetic pathway is regulated centrally by an MYB-bHLH-WD40 (MBW) complex. Anthocyanin pigmentation is an important fruit quality trait in red-fleshed kiwifruit; however, the ...underlying regulatory mechanisms involving the MBW complex are not well understood. In this study, one R2R3MYB (
expressed in fruit characteristically), one bHLH (
), two upstream regulators of
(
and
), and one WDR (
) are characterized as being involved in the regulation of anthocyanin synthesis in kiwifruit.
plays an important role in the regulation of anthocyanin accumulation by specifically activating the promoters of several anthocyanin pathway genes including
,
'
,
,
,
, and
. Coexpression of
,
, or
together with
induces much greater anthocyanin accumulation in both tobacco leaves and in
fruit compared with
alone. Moreover, this activation is further enhanced by adding
. We found that both AcMYBF110 and AcWDR1 interact with all three AcbHLH factors, while AcMYBF110 also interacts with AcWDR1 to form three different MBW complexes that have different regulatory roles in anthocyanin accumulation of kiwifruit. The AcMYBF110-AcbHLH1-AcWDR1 complex directly targets the promoters of anthocyanin synthetic genes. Other features of the regulatory pathways identified include promotion of
,
and
activities by this MBW complex, providing for both reinforcement and feedback regulation, whereas the AcMYBF110-AcbHLH4/5-AcWDR1 complex is indirectly involved in the regulation of anthocyanin synthesis by activating the promoters of
and
to amplify the regulation signals of the first MBW complex.
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