Health-promoting Anthocyanins Research Articles

Anthocyanin biosynthesis in goji berry is inactivated by deletion in a bHLH transcription factor LrLAN1b promoter.

Black goji berry (Lycium ruthenicum Murray) contains a rich source of health-promoting anthocyanins which are used in herbal medicine and nutraceutical foods in China. A natural variant producing white berries allowed us to identify two key genes involved in the regulation of anthocyanin biosynthesis in goji berries: one encoding a MYB transcription factor (LrAN2-like) and one encoding a basic helix-loop-helix (bHLH) transcription factor (LrAN1b). We previously found that LrAN1b expression was lost in the white berry variant, but the molecular basis for this phenotype was unknown. Here, we identified the molecular mechanism for loss of anthocyanins in white goji berries. In white goji, the LrAN1b promoter region has a 229 bp deletion that removes three MYB-binding elements and one bHLH-binding element, which are key to its expression. Complementation of the white goji berry LrAN1b allele with the LrAN1b promoter restored pigmentation. Virus-induced gene silencing of LrAN1b in black goji berry reduced fruit anthocyanin biosynthesis. Molecular analyses showed that LrAN2-like and another bHLH transcription factor LrJAF13 can activate LrAN1b by binding directly to the MYB-recognizing element and bHLH-recognizing element of its promoter-deletion region. LrAN1b expression is enhanced by the interaction of LrAN2-like with LrJAF13 and the WD40 protein LrAN11. LrAN2-like and LrAN11 interact with either LrJAF13 or LrAN1b to form two MYB-bHLH-WD40 complexes, which hierarchically regulate anthocyanin biosynthesis in black goji berry. This study on a natural variant builds a comprehensive anthocyanin regulatory network that may be manipulated to tailor goji berry traits.

THE EFFECT OF STORAGE TIME ON SELECTED QUALITY CHARACTERISTICS OF MIXED JUICES MADE FROM BLACK CHOKEBERRY AND HONEYSUCKLE BERRY

Background. Consumer awareness of a healthy lifestyle is gradually growing. Fruits are a rich source of health-promoting anthocyanins or polyphenols. The aim of the research was to determine the effect of the storage time of mixed juices made from black chokeberry and honeysuckle berry on selected quality characteristics. In this study, it was hypothesized that the storage time of mixed juices would be a factor affecting the content of polyphenols, anthocyanins and color. The test material included black chokeberry and honeysuckle berry juices and mixed juices with a share of juices in the range of 10 ÷ 90 %. Results and conclusions. The honeysuckle berry juice proved to be a more valuable source of poly phenols and anthocyanins (308.3 and 234.5 mg/100 cm3 ) than the chokeberry juice (229.9 mg and 122.2 mg/100 cm3 ). Similarly, the mixed juices with a higher share of honeysuckle berry juice were char acterized by a higher content of these compounds, and consequently, a potentially higher health-promoting value. The highest value of L*, a* and b* was found in the 100 % black chokeberry sample. For storage, it was demonstrated that the most intense degradation changes in the bioactive components took place in the first month, whereas in the later period, the rate of changes in these compounds was lower. The one-month storage resulted in a decrease in the content of polyphenols by 12.1 ÷ 14.2 % and anthocyanins by 19.7 ÷ 33.5 %, depending on the juice variant. In the case of color, it was observed that extending the storage time had a significant effect on the brightening of the tested products, as well as on changes in the values of the a* and b*.

Effects of ethephon and low-temperature treatments on blood oranges (Citrus sinensis L. Osbeck): Anthocyanin accumulation and volatile profile changes during storage

Health-promoting anthocyanins in blood oranges can be enriched via appropriate postharvest storage conditions. Here, we explored the changes of anthocyanin accumulation and volatile profiles of Tarocco blood oranges (Citrus sinensis L. Osbeck) treated by the low temperature alone and combined with ethephon (2 mg/mL) during 50 days of storage. The combination treatment of ethephon and low temperature (8 oC) significantly enhanced the levels of total anthocyanins (10.91 ± 0.25 mg/100 g) and individual cyanidin derivatives relative to low-temperature treatment alone. The increases of six cyanidin derivatives and three delphinidin derivatives identified by LC-MS/Q-TOF were consistent with the variation in total anthocyanins. Ethyl butanoate, ethyl 2-methylbutyrate, ethyl hexanoate, ethyl undecanoate, linalool, and d-limonene were identified as main contributors to overall aroma of fresh blood oranges. Volatile compositions and concentrations were decreased under different treatments of ethephon and temperatures, while ethephon could alleviate the loss of activity volatiles during cold storage.

Acylated anthocyanins: A review on their bioavailability and effects on postprandial carbohydrate metabolism and inflammation.

Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.

Development of Molecular Markers for Predicting Radish (Raphanus sativus) Flesh Color Based on Polymorphisms in the RsTT8 Gene.

Red radish (Raphanus sativus L.) cultivars are a rich source of health-promoting anthocyanins and are considered a potential source of natural colorants used in the cosmetic industry. However, the development of red radish cultivars via conventional breeding is very difficult, given the unusual inheritance of the anthocyanin accumulation trait in radishes. Therefore, molecular markers linked with radish color are needed to facilitate radish breeding. Here, we characterized the RsTT8 gene isolated from four radish genotypes with different skin and flesh colors. Sequence analysis of RsTT8 revealed a large number of polymorphisms, including insertion/deletions (InDels), single nucleotide polymorphisms (SNPs), and simple sequence repeats (SSRs), between the red-fleshed and white-fleshed radish cultivars. To develop molecular markers on the basis of these polymorphisms for discriminating between radish genotypes with different colored flesh tissues, we designed four primer sets specific to the RsTT8 promoter, InDel, SSR, and WD40/acidic domain (WD/AD), and tested these primers on a diverse collection of radish lines. Except for the SSR-specific primer set, all primer sets successfully discriminated between red-fleshed and white-fleshed radish lines. Thus, we developed three molecular markers that can be efficiently used for breeding red-fleshed radish cultivars.

A Transcriptional Network Makes Normal Tomato Fruit Not Purple

A Transcriptional Network Makes Normal Tomato Fruit Not Purple

Optimization of total anthocyanin content and antioxidant activity of a Hibiscus sabdariffa infusion using response surface methodology

Hibiscus sabdariffa L. calyces are underutilized sources of health-promoting anthocyanins. Infusions are the most common way to consume them, but because anthocyanins are thermosensitive, prolonged extraction times at high temperatures may reduce their bioactivities, suggesting the need to identify optimal preparation conditions. Response surface methodology was used to establish calyces-to-water ratio (X1: 1–20 g/100 mL), temperature (X2: 70–100 °C), and time (X3: 1–30 min) that would produce an infusion with optimized total anthocyanin content (TAC) and antioxidant activity. Under optimum conditions (X1=10 g/100 mL, X2=88.7 °C, and X3=15.5 min) TAC was 132.7±7.8 mg cyanidin-3-glucoside equivalents (C3G)/100 mL, and antioxidant activity was 800.6±69.9 (DPPH assay), and 1792.0±153.5 (ABTS assay) μmol Trolox equivalents (TE)/100 mL. Predicted and experimental results were statistically similar. Identifying ideal processing conditions can promote consumption of an H. sabdariffa-based functional beverage with high anthocyanin content and antioxidant activity that exert health-promoting bioactivities on the consumer.

Anthocyanin Management in Fruits by Fertilization.

Anthocyanins are water-soluble vacuolar plant pigments that are mainly synthesized in epidermal layers and the flesh of fruits such as apples, cherries, grapes, and other berries. Because of their attractive red to purple coloration and their health-promoting potential, anthocyanins are significant determinants for the quality and market value of fruits and fruit-derived products. In crops, anthocyanin accumulation in leaves can be caused by nutrient deficiency which is usually ascribed to insufficient nitrogen or phosphorus fertilization. However, it is a little-known fact that the plant's nutrient status also impacts anthocyanin synthesis in fruits. Hence, strategic nutrient supply can be a powerful tool to modify the anthocyanin content and consequently the quality and market value of important agricultural commodities. Here we summarize the current knowledge of the influence of plant nutrients on anthocyanin synthesis in fruits of major global market value and discuss the underlying cellular processes that integrate nutrient signaling with fruit anthocyanin formation. It is highlighted that fertilization that is finely tuned in amount and timing has the potential to positively influence the fruit quality by regulating anthocyanin levels. We outline new approaches to enrich plant based foods with health-promoting anthocyanins.

Varietal differences in phenolic compounds metabolism of type 2 red-fleshed apples

Apples are rich source of phenolic compounds exhibiting a strong antioxidant activity. Although type 2 red-fleshed apples highly accumulate health-promoting anthocyanins, accumulation profiles of other phenolic compounds had not been investigated. The objective of this study was to characterize the accumulation profiles of eight phenolic compounds in five type 2 red-fleshed apple varieties with different color intensities in their cortex. Quantification of the phenolic compounds revealed that not only cyanidin-3-galactoside but also chlorogenic acid and epicatechin are the dominant phenolic compounds in type 2 red-fleshed cultivars except for a red flesh lineage showing a white cortex. Bioinformatic analysis further revealed that cultivars with a deep red flesh accumulated caffeic acid and procyanidin B2, but cultivars with a pale-red flesh accumulated catechin and epicatechin. In pale-red flesh cultivars, the correlation between the expression of MdMYB110a gene responsible for the type 2 red flesh phenotype and the two phenylpropanoid pathway genes MdC3H and MdLAR were also observed during the fruit development. Taken together, these results indicate that there is a significant variation in the contents of phenolic compounds between type 2 red-fleshed cultivars and suggest the possibility that biosynthesis of some phenolic compounds other than anthocyanins is also regulated through MdMYB110a. In addition, for selecting type 2 red-fleshed cultivars efficiently, we also reported the development of a dCAPS marker which can detect functional MdMYB110a allele accurately.

Improved stability of blueberry juice anthocyanins by acidification and refrigeration

BACKGROUND: Blueberry anthocyanins are susceptible to degradation during juice processing and storage of juice at ambient temperature. Methods are needed to stabilize the health-promoting anthocyanins in blueberry and other anthocyaninrich berry juices. OBJECTIVE: In this study we determined the effect of acidification (pH 2.1, 2.5 and 2.9) of blueberry juice on changes in anthocyanins and percent polymeric color in response to juice processing and during eight months of storage at ambient and refrigerated temperatures. METHODS: Three subsamples of non-pasteurized blueberry juice were adjusted to three pH levels: 2.9 (control, no pH adjustment), 2.5, and 2.1. After pH adjustment, juices were pasteurized and placed in storage at 4 and 25◦C. Samples were analyzed before (non-pasteurized) and after pasteurization, and after 2, 4, 6, and 8 months of storage at each temperature (4 and 25◦C) for anthocyanin composition by HPLC and percent polymeric color. RESULTS: Blueberry juice acidified to pH 2.1 retained higher levels of total anthocyanins and had lower percent polymeric color values than juice acidified to pH 2.5 and control juice (pH 2.9) following pasteurization. Anthocyanin arabinosides were more susceptible to thermal degradation than glucosides, galactosides and acetylated derivatives. Levels of total anthocyanins declined markedly over 8 months of storage, but juices stored at 4◦C had on average 56% higher levels of total anthocyanins than juices stored at 25◦C. Juice acidified to pH 2.1 had on average 12% and 26% higher levels of total anthocyanins than pH 2.5 and control juices, respectively. After 8 months of storage, juice acidified to pH 2.1 had 11 and 22% higher levels of total anthocyanins than pH 2.5 and control juices stored at 4◦C, and 26% and 59% higher levels of total anthocyanins than pH 2.5 and control juices stored at 25◦C. Acetylated derivatives were more prone to losses during storage than glycosides, especially in acidified juices. CONCLUSIONS: Acidification of blueberry juice coupled with refrigerated storage are effective treatments to retain healthpromoting anthocyanins.

UV-B-induced anthocyanin accumulation in hypocotyls of radish sprouts continues in the dark after irradiation.

Raphanus sativus L. cv. Yanghua sprouts are rich in health-promoting anthocyanins; thus hypocotyls show a red color under light. In this study, effects of UV-B irradiation at 5 W m(-2) on anthocyanin biosynthesis in the hypocotyls of radish sprouts were investigated. Anthocyanins began to accumulate rapidly from 24 h irradiation and increased continuously until 48 h, showing a similar pattern to phenylalanine ammonia lyase (PAL) activity, with a correlation coefficient of 0.804. The expression of DFR and ANS paralleled the upward trend in anthocyanin accumulation, while CHS, CHI and F3H were upregulated before accumulation. When sprouts were moved into the dark from UV-B, the anthocyanin accumulation did not stop immediately. By contrast, anthocyanin accumulated continuously for more than 12 h in the dark, which was further supported by the significantly higher PAL activity monitored at 24 h after irradiation. Similarly, the transcript levels of anthocyanin biosynthesis-related genes were much higher over 6 h after 12 h UV-B irradiation. UV-B-induced anthocyanin accumulation continues in the dark after irradiation, which was supported by unfading PAL activity and high levels of biosynthesis-related genes. This will provide evidence to produce high-quality sprouts with more anthocyanins but less energy wastage in practice.

Anthocyanin accumulation and transcriptional regulation of anthocyanin biosynthesis in purple bok choy (Brassica rapa var. chinensis).

Bok choy (Brassica rapa var. chinensis) is an important dietary vegetable cultivated and consumed worldwide for its edible leaves. The purple cultivars rich in health-promoting anthocyanins are usually more eye-catching and valuable. Fifteen kinds of anthocyanins were separated and identified from a purple bok choy cultivar (Zi He) by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. To investigate the molecular mechanisms underlying anthocyanin accumulation in bok choy, the expression profiles of anthocyanin biosynthetic and regulatory genes were analyzed in seedlings and leaves of the purple cultivar and the green cultivar (Su Zhouqing). Compared with the other tissues, BrTT8 and most of the anthocyanin biosynthetic genes were significantly up-regulated in the leaves and light-grown seedlings of Zi He. The results that heterologous expression of BrTT8 promotes the transcription of partial anthocyanin biosynthetic genes in regeneration shoots of tomato indicate that BrTT8 plays an important role in the regulation of anthocyanin biosynthesis.

팬 프라잉(Pan-frying)이 찰흑미 첨가 화전의 안토시아닌 함량에 미치는 영향

Hwajeon, pan-fried rice cake, containing glutinous black rice flour at different proportions (0, 5, 10, 20, 30, or 50% of glutinous rice flour) was cooked to investigate the cooking effect on anthocyanins, color, and texture. Two anthocyanins, cyanidin-3-glucoside and peonidin-3-glucoside, were detected in both hwajeon dough and pan-fried hwajeon. The hwajeon retained up to 60% of anthocyanins in the dough after pan-frying. The lightness (L) of dough and hwajeon decreased with an increase in the amount of black rice flour rice flour. Interestingly, the lightness (L) of hwajeon was significantly lower than the counterpart dough, indicating that the color of hwajeon resulted not only from anthocyanins, but also from the browning reaction occurring during pan-frying. The redness (a) of hwajeon initially increased by adding glutinous black rice flour, and decreased at higher than 10% of black rice flour. In comparison with the control hwajeon (0% black rice flour), the black rice-added hwajeon showed lower hardness, whereas it had higher springiness and cohesiveness, resulting in no significant differences in gumminess and chewiness among the hwajeon. These results indicate that hwajeon enriched with glutinous black rice flour can be developed as a functional food containing health-promoting anthocyanins.

Anthocyanin Accumulation and Molecular Analysis of Anthocyanin Biosynthesis-Associated Genes in Eggplant (Solanum melongena L.)

Eggplant (Solanum melongena L.) is an edible fruit vegetable cultivated and consumed worldwide. The purple eggplant is more eye-catching and popular for the health-promoting anthocyanins contained in the fruit skin. Two kinds of anthocyanin were separated and identified from purple cultivar (Zi Chang) by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. To investigate the molecular mechanisms of anthocyanin accumulation in eggplant, the transcripts of anthocyanin biosynthetic and regulatory genes were analyzed in the fruit skin and the flesh of the purple cultivar and the white cultivar (Bai Xue). Compared with the other tissues, SmMYB1 and all anthocyanin biosynthetic genes except PAL were dramatically upregulated in the fruit skin of the purple cultivar. Overexpression of SmMYB1 activated abundant anthocyanin accumulation in the regenerating shoots of eggplant. These results prove that transcriptional activation of SmMYB1 accounts for constitutive upregulation of most anthocyanin biosynthetic genes and the onset of anthocyanin biosynthesis in the purple cultivar.

Neutralizing antibodies against rotavirus produced in transgenically labelled purple tomatoes

Edible fruits are inexpensive biofactories for human health-promoting molecules that can be ingested as crude extracts or partially purified formulations. We show here the production of a model human antibody for passive protection against the enteric pathogen rotavirus in transgenically labelled tomato fruits. Transgenic tomato plants expressing a recombinant human immunoglobulin A (hIgA_2A1) selected against the VP8* peptide of rotavirus SA11 strain were obtained. The amount of hIgA_2A1 protein reached 3.6 ± 0.8% of the total soluble protein in the fruit of the transformed plants. Minimally processed fruit-derived products suitable for oral intake showed anti-VP8* binding activity and strongly inhibited virus infection in an in vitro virus neutralization assay. In order to make tomatoes expressing hIgA_2A1 easily distinguishable from wild-type tomatoes, lines expressing hIgA_2A1 transgenes were sexually crossed with a transgenic tomato line expressing the genes encoding Antirrhinum majus Rosea1 and Delila transcription factors, which confer purple colour to the fruit. Consequently, transgenically labelled purple tomato fruits expressing hIgA_2A1 have been developed. The resulting purple-coloured extracts from these fruits contain high levels of recombinant anti-rotavirus neutralizing human IgA in combination with increased amounts of health-promoting anthocyanins.

Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors

Dietary consumption of anthocyanins, a class of pigments produced by higher plants, has been associated with protection against a broad range of human diseases. However, anthocyanin levels in the most commonly eaten fruits and vegetables may be inadequate to confer optimal benefits. When we expressed two transcription factors from snapdragon in tomato, the fruit of the plants accumulated anthocyanins at levels substantially higher than previously reported for efforts to engineer anthocyanin accumulation in tomato and at concentrations comparable to the anthocyanin levels found in blackberries and blueberries. Expression of the two transgenes enhanced the hydrophilic antioxidant capacity of tomato fruit threefold and resulted in fruit with intense purple coloration in both peel and flesh. In a pilot test, cancer-susceptible Trp53(-/-) mice fed a diet supplemented with the high-anthocyanin tomatoes showed a significant extension of life span.