scholarly journals Elucidating the role of shikimate dehydrogenase in controlling the production of anthocyanins and hydrolysable tannins in the outer peels of pomegranate

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Rida Habashi ◽  
Yael Hacham ◽  
Rohit Dhakarey ◽  
Ifat Matityahu ◽  
Doron Holland ◽  
...  

Abstract Background The outer peels of pomegranate (Punica granatum L.) possess two groups of polyphenols that have health beneficial properties: anthocyanins (ATs, which also affect peel color); and hydrolysable tannins (HTs). Their biosynthesis intersects at 3-dehydroshikimate (3-DHS) in the shikimate pathway by the activity of shikimate dehydrogenase (SDH), which converts 3-DHS to shikimate (providing the precursor for AT biosynthesis) or to gallic acid (the precursor for HTs biosynthesis) using NADPH or NADP+ as a cofactor. The aim of this study is to gain more knowledge about the factors that regulate the levels of HTs and ATs, and the role of SDH. Results The results have shown that the levels of ATs and HTs are negatively correlated in the outer fruit peels of 33 pomegranate accessions, in the outer peels of two fruits exposed to sunlight, and in those covered by paper bags. When calli obtained from the outer fruit peel were subjected to light/dark treatment and osmotic stresses (imposed by different sucrose concentrations), it was shown that light with high sucrose promotes the synthesis of ATs, while dark at the same sucrose concentration promotes the synthesis of HTs. To verify the role of SDH, six PgSDHs (PgSDH1, PgSDH3–1,2, PgSDH3a-1,2 and PgSDH4) were identified in pomegranate. The expression of PgSDH1, which presumably contributes to shikimate biosynthesis, was relatively constant at different sucrose concentrations. However, the transcript levels of PgSDH3s and PgSDH4 increased with the accumulation of gallic acid and HTs under osmotic stress, which apparently accumulates to protect the cells from the stress. Conclusions The results strongly suggest that the biosynthesis of HTs and ATs competes for the same substrate, 3-DHS, and that SDH activity is regulated not only by the NADPH/NADP+ ratio, but also by the expression of the PgSDHs. Since the outer peel affects the customer’s decision regarding fruit consumption, such knowledge could be utilized for the development of new genetic markers for breeding pomegranates having higher levels of both ATs and HTs.

2019 ◽  
pp. 7-14
Author(s):  
Hai Trieu Ly ◽  
Tuan Anh Vo ◽  
Viet Hong Phong Nguyen ◽  
Thi My Sa Pham ◽  
Bich Thao Lam ◽  
...  

Background: The natural antioxidants have an important role in the prevention of many diseases. The aim of study is to investigate phytochemical components, antioxidant activity and acute oral toxicity of Pomegranate (Punica granatum L.) fruit peel (PFP) extract. Materials and methods: Phytochemicals of PFP were determined by qualitative chemical tests, thin layer chromatography, total polyphenol and flavonoid contents. The PFP extract was evaluated for antioxidant activity by DPPH assay and MDA assay. In vivo acute oral toxicity test was conducted using Karber-Behrens method to determine LD50. Results: Results illustrated that PFP mainly contains flavonoids, alkaloids, tannins, triterpenes, saponins, and coumarins. PFP extract exhibited the total polyphenol and flavonoid contents with 189.97 mg gallic acid equivalent/g dry weight and 9.42 mg quercetin equivalent/g dry weight, respectively. The DPPH free radical scavenging and anti-lipid peroxidation activities of PFP extract were expressed with IC50 value of 4.80 μg/mL and 0.38 μg/ mL, sequentially. Simultaneously, the Dmax (the maximum dose administered to mice that no toxicity was observed) of PFP extract was determined to be 21.28 g/kg, equivalent to 35.64 g dried herb. Conclusion: The PFP extract is relatively safe and revealed high antioxidant activity. Key words: Punica granatum L.; polyphenols; flavonoids; gallic acid; quercetin; antioxidant activity; acute oral toxicity


2007 ◽  
Vol 17 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Huating Dou ◽  
Fred G. Gmitter

A new mandarin cultivar currently designated as selection LB8-9 [‘Clementine’ mandarin (Citrus reticulata) × ‘Minneola’ tangelo, Duncan grapefruit (Citrus paradisi) × Dancy tangerine (C. reticulata)], soon to be released by the University of Florida, Citrus Research and Education Center, Lake Alfred, has been evaluated for postharvest fruit quality and consumer acceptance. Comparisons were made with ‘Sunburst’ and ‘Minneola’ mandarins, which overlap the early and late LB8-9 maturity season, respectively. LB8-9 and ‘Sunburst’ fruit stored 2 weeks at 70 °F developed similar decay percentages (35% to 37%), while ‘Minneola’ showed only 16% decay. Postharvest pitting incidence was zero in LB8-9 and ‘Minneola’ and 3% in ‘Sunburst’ stored at 70 °F and 92% to 96% relative humidity (RH). At the same storage conditions, LB8-9 and ‘Sunburst’ developed better fruit peel color (hue = 60) in comparison with the ‘Minneola’ (hue = 65) mandarin. No differences were found in fruit external peel color (hue angle), chilling injury, or decay among three cultivars stored at 40 °F after 6 weeks. However, juice color was the best in ‘Sunburst’ as indicated by the highest color numbers (44), followed by LB8-9 (40) and ‘Minneola’ (38). Wax-formulation studies indicated that carnauba wax was the best formulation for coating LB8-9 because of low decay incidence, weight loss, and good color. No difference was found in fruit taste panels at day 6 after packing, while a better score of acceptance in the fruit taste panel was recorded for LB8-9 than ‘Minneola’ after 50 d of storage at 40 °F and 92% to 96% RH. LB8-9 fruit had a higher soluble solids concentration [SSC (14.0)] and acid (1.12) than ‘Minneola’ or ‘Sunburst’ mandarins, both having a SSC and acid lower than 11.5 and 0.86, respectively. Sucrose concentration was noticeably higher in the new cultivar (7.14 g/100 mL) than in ‘Minneola’ (5.27 g/100 mL) or ‘Sunburst’ (6.10 g/100 mL). Vitamin C concentration was 42.43 mg/100 mL for the new cultivar, which was considerably higher than ‘Minneola’ (23.27 mg/100 mL) or ‘Sunburst’ (26.25 mg/100 mL). Overall, LB8-9 has good potential as a new fresh fruit for the consumer, and no serious problems were noted with typical postharvest handling.


2021 ◽  
Vol 12 ◽  
Author(s):  
Taly Trainin ◽  
Rotem Harel-Beja ◽  
Irit Bar-Ya’akov ◽  
Zohar Ben-Simhon ◽  
Rami Yahalomi ◽  
...  

Anthocyanins are important dietary and health-promoting substances present in high quantities in the peel and arils of the pomegranate (Punica granatum L.) fruit. Yet, there is a high variation in the content of anthocyanin among different pomegranate varieties. The ‘Black’ pomegranate variety (P.G.127-28) found in Israel contains exceptionally high levels of anthocyanins in its fruit peel which can reach up to two orders of magnitude higher content as compared to that of other pomegranate varieties’ peel anthocyanins. Biochemical analysis reveals that delphinidin is highly abundant in the peel of ‘Black’ variety. The pattern of anthocyanin accumulation in the fruit peel during fruit development of ‘Black’ variety differs from that of other pomegranates. High anthocyanin levels are maintained during all developmental stages. Moreover, the accumulation of anthocyanin in the fruit peel of ‘Black’ variety is not dependent on light. Genetic analysis of an F2 population segregating for the “black” phenotype reveals that it is determined by a single recessive gene. Genetic mapping of the F2 population using single nucleotide polymorphism (SNP) markers identified few markers tightly linked to the “black” phenotype. Recombination analysis of the F2 population and F3 populations narrowed the “black” trait to an area of 178.5 kb on the draft genome sequence of pomegranate cv. ‘Dabenzi.’ A putative anthocyanidin reductase (ANR) gene is located in this area. Only pomegranate varieties displaying the “black” trait carry a base pair deletion toward the end of the gene, causing a frame shift resulting in a shorter protein. We propose that this mutation in the ANR gene is responsible for the different anthocyanin composition and high anthocyanin levels of the “black” trait in pomegranate.


2003 ◽  
Vol 31 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Vladimir Ossipov ◽  
Juha-Pekka Salminen ◽  
Svetlana Ossipova ◽  
Erkki Haukioja ◽  
Kalevi Pihlaja

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2830
Author(s):  
Aiai Zhang ◽  
Jing Zheng ◽  
Xuemiao Chen ◽  
Xueyin Shi ◽  
Huaisong Wang ◽  
...  

The peel color is an important external quality of melon fruit. To explore the mechanisms of melon peel color formation, we performed an integrated analysis of transcriptome and metabolome with three different fruit peel samples (grey-green ‘W’, dark-green ‘B’, and yellow ‘H’). A total of 40 differentially expressed flavonoids were identified. Integrated transcriptomic and metabolomic analyses revealed that flavonoid biosynthesis was associated with the fruit peel coloration of melon. Twelve differentially expressed genes regulated flavonoids synthesis. Among them, nine (two 4CL, F3H, three F3′H, IFS, FNS, and FLS) up-regulated genes were involved in the accumulation of flavones, flavanones, flavonols, and isoflavones, and three (2 ANS and UFGT) down-regulated genes were involved in the accumulation of anthocyanins. This study laid a foundation to understand the molecular mechanisms of melon peel coloration by exploring valuable genes and metabolites.


Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1187
Author(s):  
Manyou Yu ◽  
Irene Gouvinhas ◽  
Ana Barros

In recent decades, an intensive search for natural and novel types of antioxidant polyphenolics has been carried out on numerous plant materials. However, the current literature has very little information on their storage stability in the form of freshly prepared infusions. This study aims to characterize the polyphenolic composition and the antioxidant capacity of pomegranate (Punica granatum L.) leaf infusions over one-day storage (analyzed at 0, 2, 4, 6, 8, and 24 h). Spectrophotometric evaluation demonstrated that the infusion presented no significant changes in the content of total phenols (131.40–133.47 mg gallic acid g−1) and ortho-diphenols (239.91–244.25 mg gallic acid g−1). The infusion also maintained high stability (over 98% and 82%, respectively) for flavonoids (53.30–55.84 mg rutin g−1) and condensed tannins (102.15–124.20 mg epicatechin g−1), with stable (>90%) potent antioxidant capacity (1.5–2.2 mmol Trolox g−1) throughout 0–24 h storage. The main decrease was observed during 0–2 h storage of flavonoids, 8–24 h storage of tannins, and 0–4 h storage of antioxidant capacity. Chromatographic analysis further revealed that 7 decreased and 11 increased compounds were found within 0–24 h storage. The good stability of the total polyphenolics and antioxidant properties might be related to the complex conversion and activity compensation among these compounds. The findings suggest that pomegranate leaf infusion could be of great interest in the valorization of high added-value by-products and in the application of green and functional alternatives in the food-pharma and nutraceutical industries.


HortScience ◽  
2018 ◽  
Vol 53 (11) ◽  
pp. 1677-1682
Author(s):  
Olga Dichala ◽  
Ioannis Therios ◽  
Magdalene Koukourikou-Petridou ◽  
Aristotelis Papadopoulos

A field experiment was conducted in a pomegranate (Punica granatum L.) orchard of the well-known cultivars Wonderful and Acco, located in the farm of Aristotle University. The trees were sprayed, every 15 days from flowering (April) to fruit maturation (September), with solutions containing 0, 25, 50, 100 μm Ni, and 100 μm Ni + 100 μm B prepared with Ni(NO3)2·6H2O and boric acid. Leaves and fully ripe fruits were initially sorted into cracked and uncracked ones, then further separated into peel and seeds, sampled, and analyzed. Nickel sprays were effective in controlling fruit splitting as well as Ca and Mg concentration of fruit peels. The correlation between cracking level and Ni concentration in solution was linear and negative. Cracking percentage with 50 μm Ni was lower in ‘Wonderful’, whereas no difference was recorded between the cultivars in the remaining treatments. Leaves had the smallest Ni concentration compared with fruit peel and seeds. Calcium concentration of pomegranate peels was higher than that of control peel at 50 μm Ni in ‘Wonderful’. Concerning ‘Acco’, the treatments 25 μm Ni, 50 μm Ni, and 100 μm Ni + 100 μm B reduced Ca concentration, compared with control. ‘Wonderful’ fruit peel contained more phenolics than ‘Acco’. The treatments 25, 50, and 100 μm Ni increased significantly the flavonoid concentration of fruit peels. The antioxidant capacity ferric-reducing antioxidant potential (FRAP) was linearly increased with Ni concentration in solution in ‘Wonderful’, whereas in ‘Acco’ it decreased at 25 and 50 μm Ni. Our data indicates that improving Ni nutrition of pomegranate can potentially reduce crop loss due to cracking and modified phenol and flavonoid concentration and FRAP value of fruit peel.


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