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The accumulation and composition of anthocyanins in leaves of Kalanchoë blossfeldiana, detached and kept for five days under natural light conditions, were investigated. The presence of fifteen derivatives of cyanidin, petunidin, and delphinidin was found. Changes in the content of each anthocyanin in the leaves before and after exposure to light on the abaxial (naturally upper) and adaxial (naturally lower) sides of the leaves were compared. When the adaxial side was exposed to light, the anthocyanin contents of the leaves did not change. In contrast, when the abaxial side of detached leaves was exposed to light, there was enhanced accumulation of delphinidin-rhamnoside-glucoside, cyanidin-rhamnoside-glucoside, cyanidin-glucoside-glucoside, and two unknown derivatives of petunidin and delphinidin. Application of methyl jasmonate (JA-Me) on the abaxial side exposed to light inhibited the accumulation of these anthocyanins. This effect could probably be due to the presence of these anthocyanins in the epidermal cells of K. blossfeldiana leaves and was visible in the microscopic view of its cross-section. These anthocyanins were directly exposed to JA-Me, leading to inhibition of their formation and/or accumulation. The lack of significant effects of JA-Me on anthocyanin mono- and tri-glycosides may indicate that they are mainly present in the mesophyll tissue of the leaf.

Anthocyanins are polyphenol compounds that render various hues of pink, red, purple, and blue in flowers, vegetables, and fruits. Anthocyanins also play significant roles in plant propagation, ecophysiology, and plant defense mechanisms. Structurally, anthocyanins are anthocyanidins modified by sugars and acyl acids. Anthocyanin colors are susceptible to pH, light, temperatures, and metal ions. The stability of anthocyanins is controlled by various factors, including inter and intramolecular complexations. Chromatographic and spectrometric methods have been extensively used for the extraction, isolation, and identification of anthocyanins. Anthocyanins play a major role in the pharmaceutical; nutraceutical; and food coloring, flavoring, and preserving industries. Research in these areas has not satisfied the urge for natural and sustainable colors and supplemental products. The lability of anthocyanins under various formulated conditions is the primary reason for this delay. New gene editing technologies to modify anthocyanin structures in vivo and the structural modification of anthocyanin via semi-synthetic methods offer new opportunities in this area. This review focusses on the biogenetics of anthocyanins; their colors, structural modifications, and stability; their various applications in human health and welfare; and advances in the field.

This study aimed to optimize the ultrasound-assisted extraction (UAE) of total anthocyanins from two stages of ripening purple tomatoes (low and high) and to compare the optimized extraction with the conventional one. In the optimization of UAE, the studied variables were time (5 to 75 min), temperature (30 to 70 [degrees]C), and solid: liquid ratio (1:5 to 1:15 m/v). The optimal condition of the UAE process, for low-ripened purple tomatoes, occurs at a time of 75 min, temperature of 40 [degrees]C, and solid: liquid ratio of 1:15 m/v, predicting the content of 12.487 mg/100g. For high-ripened purple tomatoes, the optimal condition occurs at a time of 40 min, temperature of 50 [degrees]C, and solid: liquid ratio of 1:15 m/v, predicting the content of 8.802 mg/100 g. On validation of these optimized conditions, less than a 3% difference was reported between the predicted and experimental values (12.267 mg/100 g for low-ripened, and 8.894 mg/100 g for high-ripened purple tomatoes). When comparing the optimized UAE with the conventional extraction, it was observed that UAE increased (P < 0.05) the extraction of total anthocyanins content by 73% for low-ripened and by 54% for high-ripened purple tomatoes. Thus, the study indicated that the UAE is an efficient technology for recovering bioactive compounds from purple tomatoes. Key words: ultrasonic extraction * optimization * anthocyanins * purple tomatoes. Este estudo teve como objetivo otimizar a extração assistida por ultrassom (EAU) de antocianinas totais de dois estágios de maturação de tomates roxos (baixo e alto) e comparar a extração otimizada com a convencional. Na otimização da EAU, as variáveis estudadas foram tempo (5 a 75 min), temperatura (30 a 70 [degrees]C) e razão sólido:líquido (1:5 a 1:15 m/v). A condição otimizada da EAU, para tomates roxos em baixa maturação, ocorreu no tempo de 75 min, temperatura de 40 [degrees]C e razão sólido:líquido de 1:15 m/v, prevendo o teor de 12,487 mg/100 g. Para tomates roxos em alta maturação, a condição ideal ocorreu no tempo de 40 min, temperatura de 50 [degrees]C e razão sólido:líquido de 1:15 m/v, prevendo o teor de 8,802 mg/100 g. Na validação das condições otimizadas, foi encontrada uma diferença inferior a 3% entre os valores previstos e experimentais (12,267 mg/100g para baixa-maturação e 8,894 mg/100 g para alta-maturação). Ao comparar a EAU otimizada com a convencional, observou-se que a EAU aumentou (P < 0,05) a extração de antocianinas totais em 73% para tomates em baixa-maturação e 54% para tomates roxos em alta-maturação. Assim, o estudo indica que os EAU é uma tecnologia eficiente para a recuperação de antocianinas de tomates roxos. Palavras-chave: extração ultrassônica, otimização, antocianinas, tomates roxos.

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To explore the composition of anthocyanins and expand their biological activities, anthocyanins were systematically isolated and purified from tubers of Solanum tuberosum L., and their tyrosinase inhibitory activity was investigated. In this study, two new anthocyanin degradation compounds, norpetanin (9) and 4-O-(p-coumaryl) rhamnose (10), along with 17 known anthocyanins and their derivatives, were isolated and purified from an acid-ethanolic extract of fresh purple potato tubers. Their structures were elucidated via 1D and 2D NMR and HR-ESI-MS and compared with those reported in the literature. The extracts were evaluated for anthocyanins and their derivatives using a tyrosinase inhibitor screening kit and molecular docking technology, and the results showed that petanin, norpetanin, 4-O-(p-coumaryl) rhamnose, and lyciruthephenylpropanoid D/E possessed tyrosinase inhibitory activity, with 50% inhibiting concentration (IC[sub.50]) values of 122.37 ± 8.03, 115.53 ± 7.51, 335.03 ± 12.99, and 156.27 ± 11.22 μM (Mean ± SEM, n = 3), respectively. Furthermore, petanin was validated against melanogenesis in zebrafish; it was found that it could significantly inhibit melanin pigmentation (p < 0.001), and the inhibition rate of melanin was 17% compared with the normal group. This finding may provide potential treatments for diseases with abnormal melanin production, and high-quality raw materials for whitening cosmetics.

Anthocyanins are considered as the largest group of water-soluble pigments found in the vacuole of plant cells, displaying range of colors from pink, orange, red, purple and blue. They belong to flavonoids, a polyphenolic subgroup. Application of anthocyanins in food systems as natural food colourants is limited due to the lack of stability under different environmental conditions such as light, pH, heat etc. Anthocyanins esterified with one or more acid groups are referred as acylated anthocyanins. Based on the presence or absence of acyl group, anthocyanins are categorized as acylated and nonacylated anthocyanins. Acylated anthocyanins are further classified as mono, di, tri, tetra acylated anthocyanins according to the number of acyl groups present in the anthocyanin. This review classifies common anthocyanin sources into non-acylated, mono-, di-, tri- and tetra-acylated anthocyanins based on the major anthocyanins present in these sources. The relative stabilities of these anthocyanins with respect to thermal, pH and photo stress in beverage systems are specifically discussed. Common anthocyanin sources such as elderberry, blackberry, and blackcurrant mainly contain nonacylated anthocyanins. Red radish, purple corn, black carrot also mainly contain mono acylated anthocyanins. Red cabbage and purple sweet potato have both mono and diacylated anthocyanins. Poly acylated anthocyanins show relatively higher stability compared with nonacylated and monoacylated anthocyanins. Several techniques such as addition of sweeteners, co-pigmentation and acylation techniques could enhance the stability of nonacylated anthocyanins. Flowers are main sources of polyacylated anthocyanins having higher stability, yet they have not been commercially exploited for their anthocyanins.

Most broccoli cultivars or accessions exhibit green buds under appropriate growth conditions, which turn purple at cold temperatures. However, certain cultivars consistently maintain green buds both during normal growth and at cold temperatures. In this study, we used BSA-seq (bulked segregation analysis-sequencing), along with fine mapping and transcriptome analysis to identify a candidate gene (flavonoid 3′-hydroxylase, F3′H) responsible for reducing anthocyanin accumulation in the mutant GS and HX-16 broccoli (Brassica oleracea L. var. italica), which could retain green buds even at low temperatures. A 43-bp deletion was detected in the coding sequence (CDS) of the F3′H gene in HX-16 and the mutant GS, which significantly decreased F3′H expression and the accumulation of cyanidin and delphinidin in the mutant GS. Furthermore, the expression of F3′H was upregulated at low temperatures in the wild line PS. Our results demonstrated the efficacy of utilizing the 43-bp InDel (Insertion–Deletion) in predicting whether buds in B. oleracea L. will turn purple or remain green at cold temperatures across forty-two germplasm materials. This study provides critical genetic and molecular insights for the molecular breeding of B. oleracea and sheds light on the molecular mechanisms underlying the effect of low temperatures on bud color in broccoli.

The peel color of pomegranates is an important exterior quality that determines market value. Anthocyanins are biosynthesized in the cytosol and then transported to the vacuole for storage. However, the molecular mechanism that determines the color variation between red and white pomegranates remains unclear. In this study, we identified an R2R3-MYB protein (PgMYB1) that interacts with the PgGSTF6 promoter and regulates its transcriptional expression, thus promoting the accumulation of anthocyanins in pomegranate. The expression of PgMYB1 and PgGSTF6 was positively correlated with the anthocyanin content in red and white pomegranates. Further investigation showed that the knockdown of PgMYB1 in red pomegranate 'Taishanhong' (TSH), by the virus-induced gene-silencing system, inhibited anthocyanin accumulation. Together, our results indicate that PgMYB1 controls the transport of anthocyanin via PgGSTF6 and thus promotes anthocyanin accumulation in red pomegranates. Our results have a certain reference value for further clarifying the regulation of anthocyanin synthesis and transport in pomegranate fruits.

Purpose Dietary flavonoids, including anthocyanins, may positively influence cognition and may be beneficial for the prevention and treatment of dementia. We aimed to assess whether daily consumption of anthocyanin-rich cherry juice changed cognitive function in older adults with dementia. Blood pressure and anti-inflammatory effects were examined as secondary outcomes. Methods A 12-week randomised controlled trial assessed cognitive outcomes in older adults (+70 year) with mild-to-moderate dementia ( n  = 49) after consumption of 200 ml/day of either a cherry juice or a control juice with negligible anthocyanin content. Blood pressure and inflammatory markers (CRP and IL-6) were measured at 6 and 12 weeks. ANCOVA controlling for baseline and RMANOVA assessed change in cognition and blood pressure. Results Improvements in verbal fluency ( p  = 0.014), short-term memory ( p  = 0.014) and long-term memory ( p  ≤ 0.001) were found in the cherry juice group. A significant reduction in systolic ( p  = 0.038) blood pressure and a trend for diastolic ( p  = 0.160) blood pressure reduction was evident in the intervention group. Markers of inflammation (CRP and IL-6) were not altered. Conclusion Inclusion of an anthocyanin-rich beverage may be a practical and feasible way to improve total anthocyanin consumption in older adults with mild-to-moderate dementia, with potential to improve specific cognitive outcomes.

Summary The red coloration of pear (Pyrus pyrifolia) results from anthocyanin accumulation in the fruit peel. Light is required for anthocyanin biosynthesis in pear. A pear homolog of Arabidopsis thaliana BBX22, PpBBX16, was differentially expressed after fruits were removed from bags and may be involved in anthocyanin biosynthesis. Here, the expression and function of PpBBX16 were analysed. PpBBX16's expression was highly induced by white‐light irradiation, as was anthocyanin accumulation. PpBBX16's ectopic expression in Arabidopsis increased anthocyanin biosynthesis in the hypocotyls and tops of flower stalks. PpBBX16 was localized in the nucleus and showed trans‐activity in yeast cells. Although PpBBX16 could not directly bind to the promoter of PpMYB10 or PpCHS in yeast one‐hybrid assays, the complex of PpBBX16/PpHY5 strongly trans‐activated anthocyanin pathway genes in tobacco. PpBBX16's overexpression in pear calli enhanced the red coloration during light treatments. Additionally, PpBBX16's transient overexpression in pear peel increased anthocyanin accumulation, while virus‐induced gene silencing of PpBBX16 decreased anthocyanin accumulation. The expression patterns of pear BBX family members were analysed, and six additional BBX genes, which were differentially expressed during light‐induced anthocyanin biosynthesis, were identified. Thus, PpBBX16 is a positive regulator of light‐induced anthocyanin accumulation, but it could not directly induce the expression of the anthocyanin biosynthesis‐related genes by itself but needed PpHY5 to gain full function. Our work uncovered regulatory modes for PpBBX16 and suggested the potential functions of other pear BBX genes in the regulation of anthocyanin accumulation, thereby providing target genes for further studies on anthocyanin biosynthesis.