Proanthocyanidin Content Research Articles

R2R3-MYB gene family: Genome-wide identification provides insight to improve the content of proanthocyanidins in Trifolium repens

The R2R3-MYB family is one of largest transcription factor families in plants playing significant roles in regulating anthocyanin and proanthocyanidin biosynthesis. Proanthocyanidins are one of major objectives to improve the quality of white clover (Trifolium repens L.), which have a beneficial effect on ruminant to prevent the lethal pasture bloat. A total of 133 TrR2R3-MYB genes were identified and distributed on all 16 chromosomes based on the whole genome information of white clover. Also, by exploring the gene structure, motifs and duplication events of TrR2R3-MYBs, as well as the evolutionary relationship with TrR2R3-MYB genes of other species, 10 TrR2R3-MYB genes with the potential to regulate the anthocyanins and proanthocyanidins biosynthesis were screened. These TrR2R3-MYB genes responded significantly to low temperature in white clover. In addition, they have different expression patterns in leaves, petioles and inflorescences of white clover. Importantly, TrMYB116 and TrMYB118 may positively regulate anthocyanin accumulation and low temperature response in white clover. TrMYB118 may also be associated with anthocyanin pigmentation pattern in Purple leaves. This study provides a basis for verifying the function of TrR2R3-MYB and breeding white clover cultivars with high proanthocyanidins.

Analyses on the pigment composition of different seed coat colors in adzuki bean.

Seed coat color is an important quality and domestication trait. The adzuki bean has more than a dozen seed coat colors closely associated with the anthocyanin and flavonoid metabolism pathways. In this study, we explored the pigment composition of 10 different seed coat color adzuki beans including red, black mottle on red, black mottle on gray, golden, green, black, ivory, brown, and light brown. The results showed that anthocyanins are the main pigment in adzuki bean seed coat. There were no carotenoid or pelargonidin derivatives in the seed coats of any accessions. Different colors of adzuki bean seed coat have different pigment compositions and the combination of procyanidins and anthocyanins affected seed coat color. The ivory seed coat had an extremely low proanthocyanidin and anthocyanin content. Only the green adzuki bean seed coats contained chlorophyll. Our results explain the pigment composition of the different seed coat colors and the combination of proanthocyanidins and anthocyanins affected seed coat color in adzuki bean. These results can provide a theoretical basis for the study of adzuki bean coloring mechanism.

A novel thiolysis-high-performance liquid chromatography method for the determination of proanthocyanidins in grape seeds.

A novel thiolysis-high-performance liquid chromatography method for the quantitative determination of total proanthocyanidins and the mean degree of polymerization in grape seeds has been developed. Following thiolysis with formic acid and benzyl mercaptan, reaction products were separated and purified. Three proanthocyanidin monomers and three derivatives were obtained and their structures were identified by liquid chromatography-mass spectrometry, FTIR spectroscopy, and NMR spectroscopy. A decomposition model of the thiolysis products and a correction formula for proanthocyanidins concentration were established. This thiolysis-high-performance liquid chromatography method displayed good calibration linearity (R2 >0.999 over the concentration range 0.01 to 10mg/mL), excellent accuracy (recoveries of 97.9-99.6%), and precision (repeatability relative standard deviations of 0.45-0.75%). This method is suitable for the quantitative analysis of proanthocyanidins in grape seed products.

Interactions of Vitis vinifera L. cv. Pinot Noir grape anthocyanins with seed proanthocyanidins and their effect on wine color and phenolic composition

The initial concentration of anthocyanin and proanthocyanidin in wine affects the development of SO2-resistant pigments, as well as color and non-color contributing polymeric fractions. However, the effect of extracted monomeric Pinot Noir (Vitis vinifera L. cv.) grape anthocyanins with seed proanthocyanidins are poorly studied. In model ferments, the reaction of purified Vitis vinifera L. cv. Pinot noir monomeric anthocyanins with seed proanthocyanidins extract were investigated at high and low concentrations of each reactant. During wine aging, monomeric anthocyanins decreased whereas SO2-resistant pigments increased. Higher anthocyanin concentrations retained more soluble tannins in model ferments during aging, while those with higher anthocyanin and lower proanthocyanidin concentrations had the highest MCP-tannin concentration in model ferments. HPLC analysis showed that the color contributing polymeric fractions are dependent upon the initial concentration of anthocyanin/proanthocyanidin ratios and more inclined towards high anthocyanin/low proanthocyanidin concentrations. Wine color parameters were measured in the form of L*, a*, b*, C (chroma) and H (hue) values and showed a decrease in hue and chroma in model wines after aging. The color data supported the HPLC findings that the initial anthocyanin/proanthocyanidin ratio was critical for the establishment of a color contributing polymeric fractions and stable deep red color in wines.

EFFECTS OF ORGANIC AND CHEMICAL FERTILIZERS ON THE CONTENT OF MAJOR PHENOLIC COMPOUNDS OF CARROT

Carrot is a popular winter vegetable rich in health-promoting phenolic compounds. In this study, different chemical and organic fertilizers were used during cultivation to observe the effect on major phenolic compounds (total phenols, total flavonoids, and proanthocyanidins) of carrot roots. Total five treatments which are F1=100% organic fertilizer, F2= 100% chemical fertilizer, F3= 75% chemical + 25% organic fertilizer, F4= 50% chemical + 50% organic fertilizer (of recommended dose) and F5= local control with three replications were applied in the experiment designed in Randomized Completed Block Design (RCBD). The contents of total phenols varied significantly in response to the chemical and organic fertilizer treatment. The highest amount of total phenols (10.549 mg kg-1) was found in F2 treatments where 100% chemical fertilizer of the recommended dose was applied, and the lowest amount (7.126 mg kg-1) was found in F5 treatment where no fertilizer was applied. The content of total flavonoids and proanthocyanidins did not vary significantly in response to the fertilizer treatments. Based on the current study, it is not proven that organically fertilized carrot contains more amount of health-promoting phenolic compounds than chemically fertilized carrot.

Supercritical Fluid and Conventional Extractions of High Value-Added Compounds from Pomegranate Peels Waste: Production, Quantification and Antimicrobial Activity of Bioactive Constituents.

This study is focused on different extractions (Cold Maceration (CM), Ultrasonic Extraction (UE), Soxhlet Extraction (SE) and Supercritical Fluid Extraction (SFE)) of bioactive compounds from pomegranate (Punica Granatum L.) fruit peels using methanol, ethanol, and acetone as solvents in conventional extractions and changing operating pressure (10, 15, 20, 25 MPa) in SFE, respectively. The extraction yields, total phenols (TP) and proanthocyanidins (PAC) contents, and antioxidant activity of different extracts are revealed. TP and PAC recovered by extracts ranged from 24.22 to 42.92 mg gallic acid equivalents (GAE)/g and 2.01 to 5.82 mg PAC/g, respectively. The antioxidant activity of extracts ranged from 84.70% to 94.35%. The phenolic compound identification and quantification in selective extracts was done using the LC-MS/MS method. The contents of different flavonoids and phenolic acids have been determined. SFE extract, obtained at 20 MPa, contained the highest content (11,561.84 μg/g) of analyzed total polyphenols, with predominant ellagic acid (7492.53 μg/g). For the first time, Microbial Growth Inhibition Rates (MGIRs) were determined at five different concentrations of pomegranate SFE extract against seven microorganisms. Minimal Inhibitory Concentration (MIC90) was determined as 2.7 mg/mL of SFE pomegranate peel extract in the case of five different Gram-negative and Gram-positive bacteria.

Fatty acid profile, secondary compounds and antioxidant activities in the fresh forage, hay and silage of sainfoin (Onobrychis viciifolia) and sulla (Hedysarum coronarium).

BackgroundSainfoin (Onobrychis viciifolia) and sulla (Hedysarum coronarium) are forage legumes usually preserved to optimize their utilization as feedstuffs. However, the method of preservation modifies the chemical composition differently in both legume species. Secondary compounds (such as proanthocyanidins, fatty acids, carotenoids and tocopherols) present in forages affect the quality of animal products. Therefore, the effect of preservation on the contents of secondary compounds should be investigated. Accoridngly, samples of sainfoin and sulla were directly freeze‐dried (fresh), dried at ambient temperature (hay) and vacuum‐packaged for 82 days (silage).ResultsIn both legumes, the total fatty acid and C18:3 n‐3 contents decreased and C16:0 increased with preservation (P < 0.001), with a greater effect for the hays than for the silages. For both legumes, the lutein, neoxanthin and violaxanthin contents decreased to a greater extent in the silages than in the hays (P < 0.001). Both hays exhibited the lowest β‐carotene concentrations (P < 0.001). The α‐tocopherol contents decreased in hays, but not in silages, compared to the fresh forages of both legumes (P < 0.001). The antioxidant activities were lower in the silages than in the hays and fresh forages (P < 0.001) and were very strongly related to the contents of polyphenols and proanthocyanidins (P < 0.001).ConclusionHaymaking affected the fatty acid, carotenoid and α‐tocopherol contents to a greater extent but had a lesser effect on the antioxidant activities than silage‐making, which were very strongly related to their contents of polyphenols and proanthocyanidins. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

In vitro assessment of the bioavailability of bioactive non-extractable polyphenols obtained by pressurized liquid extraction combined with enzymatic-assisted extraction from sweet cherry (Prunus avium L.) pomace

In vitro digestion and absorption simulation processes of non-extractable polyphenols (NEPs) obtained by pressurized liquid extraction combined with enzymatic-assisted extraction with Promod enzyme (PLE-EAE) from the residue of conventional extraction of sweet cherry pomace were studied. In general, total phenolic and proanthocyanidin contents decreased in each phase of the digestion. However, the antioxidant capacity increased when the digestion process progressed. In addition, the highest total phenolic and proanthocyanidin contents and antioxidant capacity were obtained in the absorbed fraction. NEPs from PLE-EAE extract, digestive fractions, absorbed and unabsorbed fractions were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization quadrupole Exactive-Orbitrap mass spectrometry (UHPLC-ESI-Q-Orbitrap-MS). Fifteen NEPs were identified in the intestinal fraction and five in the absorbed fraction after the digestion process. Results obtained in this study define for the first time the bioavailability of antioxidant NEPs obtained from sweet cherry pomace.

TRIPTYCHON-LIKE regulates aspects of both fruit flavor and color in citrus

Deciphering the genetic basis of organoleptic traits is critical for improving the quality of fruits, which greatly shapes their appeal to consumers. Here, we characterize the citrus R3-MYB transcription factor TRIPTYCHON-LIKE (CitTRL), which is closely associated with the levels of citric acid, proanthocyanidins (PAs), and anthocyanins. Overexpression of CitTRL lowered acidity levels and PA contents in citrus calli as well as anthocyanin and PA contents in Arabidopsis leaves and seeds. CitTRL interacts with the two basic helix-loop-helix (bHLH) proteins CitbHLH1 and ANTHOCYANIN 1 (CitAN1) to regulate fruit quality. We show that CitTRL competes with the R2R3-MYB CitRuby1 for binding to CitbHLH1 or CitAN1, thereby repressing their activation of anthocyanin structural genes. CitTRL also competes with a second R2R3-MYB, CitPH4, for binding to CitAN1, thus altering the expression of the vacuolar proton-pump gene PH5 and Leucoanthocyanidin reductase, responsible for vacuolar acidification and proanthocyanidins biosynthesis, respectively. Moreover, CitPH4 activates CitTRL transcription, thus forming an activator-repressor loop to prevent the overaccumulation of citric acid and PAs. Overall, this study demonstrates that CitTRL acts as a repressor of the accumulation of citric acid, PAs, and anthocyanins by a cross-regulation mechanism. Our results provide an opportunity to simultaneously manipulate these key traits as a means to produce citrus fruits that are both visually and organoleptically appealing.

Adaptive Responses of Common and Hybrid Bermudagrasses to Shade Stress Associated With Changes in Morphology, Photosynthesis, and Secondary Metabolites.

Alteration of ploidy in one particular plant species often influences their environmental adaptation. Warm-season bermudagrass is widely used as forage, turfgrass, and ground-cover plant for ecological remediation, but exhibits low shade tolerance. Adaptive responses to shade stress between triploid hybrid bermudagrass cultivars [“Tifdwarf” (TD), “Tifsport” (TS), and “Tifway” (TW)] and tetraploid common bermudagrass cultivar “Chuanxi” (CX) were studied based on changes in phenotype, photosynthesis, and secondary metabolites in leaves and stems. Shade stress (250 luminance, 30 days) significantly decreased stem diameter and stem internode length, but did not affect the leaf width of four cultivars. Leaf length of CX, TD, or TW showed no change in response to shade stress, whereas shade stress significantly elongated the leaf length of TS. The CX and the TS exhibited significantly higher total chlorophyll (Chl), Chl a, carotenoid contents, photosynthetic parameters [PSII photochemical efficiency (Fv/Fm), transpiration rate, and stomatal conductance] in leaves than the TW and the TD under shade stress. The CX also showed a significantly higher performance index on absorption basis (PIABS) in leaf and net photosynthetic rate (Pn) in leaf and stem than the other three cultivars under shade stress. In addition, the TS maintained higher proantho cyanidims content than the TW and the TD after 30 days of shade stress. Current results showed that tetraploid CX exhibited significantly higher shade tolerance than triploid TD, TS, and TW mainly by maintaining higher effective photosynthetic leaf area, photosynthetic performance of PSI and PSII (Pn and Fv/Fm), and photosynthetic pigments as well as lower Chl a/b ratio for absorption, transformation, and efficient use of light energy under shade stress. For differential responses to shade stress among three triploid cultivars, an increase in leaf length and maintenance of higher Fv/Fm, gas exchange, water use efficiency, carotenoid, and proanthocyanidin contents in leaves could be better morphological and physiological adaptations of TS to shade than other hybrid cultivars (TD and TW).

Physicochemical and antioxidant activity of fruit harvested from eight jujube (Ziziphus jujuba Mill.) cultivars at different development stages

Jujube is a crop highly resistant to drought and salinity, making it one of the main fruit trees in Xinjiang. The present study evaluated the changes in the physicochemical and antioxidant activities of jujube fruit of eight different cultivars from Xinjiang, China. The developmental stages were selected according to the days after full bloom and fruit peel colour during ripening; these stages included young (S1), fruit core-hardening (S2), green ripening (S3), half-red maturity (S4) and complete red. In present study, different cultivars of jujube fruit showed similar chemical profiles, but their amounts showed great variation. HZ had the highest content of sugars, and JY had the highest content of cAMP and cGMP, while relatively higher levels of ascorbic acid, catechin, epicatechin, rutin, proanthocyanidin and antioxidant activity were found in ‘FS’ than in other cultivars, indicating that ‘FS’ could be used as a potential natural antioxidant. Regarding the development stages of jujube fruit, the moisture, ascorbic acid, total polyphenol, catechin, epicatechin, proanthocyanidin and rutin contents decreased during the development of all jujube cultivars, while the fructose, glucose, sucrose, cAMP, and cGMP contents greatly increased. The antioxidant activity determined by DPPH and ABTS radical scavenging decreased as the fruits matured. Therefore, the results suggest that green jujube (S1) could be used for natural antioxidants (catechin, epicatechin, proanthocyanidin) and that the advanced ripening stage(S5) is the proper picking period for fresh fruit and commercial processing.

Sainfoin in the Dams' Diet as a Source of Proanthocyanidins: Effect on the Growth, Carcass and Meat Quality of Their Suckling Lambs.

Simple SummarySeveral studies point out that the use of local forage legumes, such as sainfoin, can be appropriate for feeding sheep autochthonous breeds, with additional benefits also for the soil. Besides, sainfoin has a medium content of proanthocyanidins (PAC), also known as condensed tannins, the effects of which have been studied in fattening lambs but seldom on suckling lambs. The aim of the study was to evaluate the effect of PAC of sainfoin fed to dams on the productive traits, weight of the digestive organs, and on carcass and meat quality of their suckling lambs. The inclusion of PAC from sainfoin in the dam diet did not produce detrimental changes on the growth and carcass and meat characteristics of their suckling lambs. Therefore, sainfoin can be fed to ewes during lactation to produce suckling lambs, achieving good performances and meat quality.Sainfoin (Onobrychis viciifolia) is a forage legume with a medium content of proanthocyanidins (PAC), which may affect animal performance and product quality. The objective of the present study was to assess the effect of PAC from sainfoin fed to dams, using polyethylene glycol (PEG) as a blocking agent, on the performance and carcass and meat quality of their suckling male lambs. After lambing, twenty lactating dams were fed fresh sainfoin ad libitum plus 200 g per day of barley; ten were orally dosed with water (Sainfoin), and ten were dosed orally with a water dilution of 100 g PEG (Sainfoin + PEG). Their lambs (4.1 ± 0.64 kg at birth) suckled ad libitum until they reached the target slaughter weight of 10–12 kg. The presence of PAC in the dams’ diet did not affect the growth, blood metabolites and carcass weight and fatness of the suckling lambs but decreased the lightness of caudal fat (p < 0.05) and increased the weight of the digestive compartments (p < 0.05). Regarding the meat characteristics, PAC only decreased polyphenols content (p < 0.05). In conclusion, the presence of PAC in the dams’ diet had not significant effects on the performance and product quality of their suckling lambs.

R2R3-MYB Transcription Factor NtMYB330 Regulates Proanthocyanidin Biosynthesis and Seed Germination in Tobacco (Nicotiana tabacum L.).

Proanthocyanidins (PAs) are important phenolic compounds and PA biosynthesis is regulated by a ternary MBW complex consisting of a R2R3-MYB regulator, a bHLH factor and a WDR protein. In this study, a tobacco R2R3-MYB factor NtMYB330 was characterized as the PA-specific regulator in which the PA biosynthesis was promoted in the flowers of NtMYB330-overexpressing lines while decreased in the flowers of ntmyb330 mutants. NtMYB330 can interact with flavonoid-related bHLH partner NtAn1b and WDR protein NtAn11-1, and the NtMYB330-NtAn1b complex is required to achieve strong transcriptional activation of the PA-related structural genes NtDFR1, NtANS1, NtLAR1 and NtANR1. Our data reveal that NtMYB330 regulates PA biosynthesis in seeds and affects seed germination, in which NtMYB330-overexpressing lines showed higher PA accumulations in seed coats and inhibited germination, while ntmyb330 mutants had reduced seed coat PAs and improved germination. NtMYB330 affects seed germination possibly through two mechanisms: modulating seed coat PAs to affect coat-imposed dormancy. In addition, NtMYB330 regulates the expressions of abscisic acid (ABA) and gibberellin acid (GA) signaling-related genes, affecting ABA-GA crosstalk and seed germination. This study reveals that NtMYB330 specifically regulates PA biosynthesis via formation of the MBW complex in tobacco flowers and affects germination through adjustment of PA concentrations and ABA/GA signaling in tobacco seeds.

Extraction and Quantification of Chlorophylls, Carotenoids, Phenolic Compounds, and Vitamins from Halophyte Biomasses

Halophytes are salt-tolerant plants, and they have been utilised as healthy, nutritious vegetables and medicinal herbs. Various studies have shown halophytes to be rich in health-beneficial compounds with antioxidant activity, anti-inflammatory and antimicrobial effects, and cytotoxic properties. Despite their potential, these plants are still underutilised in agriculture and industrial applications. This review includes the state-of-the-art literature concerning the contents of proanthocyanidins (also known as condensed tannins), total phenolic compounds, photosynthetic pigments (chlorophyll and carotenoids), and vitamins in various halophyte biomasses. Various extraction and analytical methods are also considered. The study shows that various species have exhibited potential for use not only as novel food products but also in the production of nutraceuticals and as ingredients for cosmetics and pharmaceuticals.

Pro-inflammatory enzyme inhibition and antioxidant activity of six scientifically unexplored indigenous plants traditionally used in South Africa to treat wounds

Six indigenous medicinal plants species, Agapanthus inapertus, Cheilanthes hirta, Crassula capitella, Eriospermum flagelliforme, Euphorbia clavarioides and Pelargonium alchemilloides are used traditionally in South Africa to treat wounds without scientific evidence as wound healing agents. Consequently, this study sought to investigate the antioxidant and anti-inflammatory activities of these plants species as a first step towards their validation as wound healing agents. The 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), ferric reducing antioxidant power (FRAP), and β-carotene-linoleic acid model system (β-CLAMS) assays were used to test for antioxidant activity. The inhibition of the xanthine oxidase (XO), cyclooxygenase -2 (COX-2) and 15- lipoxygenase (15-LOX) as well as the extracts’ ability to preserve the cyclooxygenase-1 (COX-1) enzyme activity were used as anti-inflammatory models. Furthermore, the total phenolics, flavonoids and proanthocyanidins content were quantified using standard methods. Species, C. hirta displayed high flavonoid and proanthocyanidin content whilst C. capitella displayed high phenolic content, and good activity against the four used antioxidant models compared to standards, butylated hydroxytoluene and ascorbic acid. Majority of the extracts displayed significantly higher anti-xanthine oxidase activity, outperforming standard quercetin. The acetone extracts of A. inapertus (IC50 = 57.33 ± 0.30 µg/mL), E. flagelliforme (IC50 = 52.10 ± 0.98 µg/mL), P. alchemilloides (IC50 = 58.28 ± 0.94 µg/mL) and E. clavarioides water (IC50 = 50.53 ± 0.47 µg/mL) extract displayed moderate 15-LOX inhibition compared to standard, nordihydroguaiaretic acid (IC50 = 0.45 ± 0.01 µg/mL). The acetone extracts of C. capitella (IC50 = 3.16 ± 0.06 µg/mL), E. flagelliforme (IC50 = 1.13 ± 0.09 µg/mL), E. clavarioides (IC50 = 1.84 ± 0.18 µg/mL), P. alchemilloides (IC50 = 1.13 ± 0.14 µg/mL), and the E. clavarioides water extract (IC50 = 1.18 ± 0.11 µg/mL) displayed COX-2 inhibition comparable to that of standard, aspirin (IC50 = 1.11 ± 0.03 µg/mL). At some degree, all tested extracts preserved the activity of the COX-1 enzyme with the E. clavarioides acetone extract significantly preserving the activity of COX-1 (IC50 = 96.21 ± 0.18 µg/mL), compared to standard, aspirin (IC50 = 0.98 ± 0.06 µg/mL). The antioxidant and anti-inflammatory activities displayed by these medicinal plants support their application and beneficial effect in wounds healing and hold promising prospects as natural alternatives to the existing conventional treatments.

Identification and quantification of oligomeric proanthocyanidins, alkaloids, and flavonoids in lotus seeds: A potentially rich source of bioactive compounds

Untargeted metabolomics was performed to study the profiles of 101 chemicals in lotus seeds using ultrahigh-performance liquid chromatography–photodiode array detection–high-resolution tandem mass spectrometry. Among them, 16 dimeric, 18 trimeric, and 4 tetrameric proanthocyanidins were theoretically identified based on the degree of polymerization, and the number of linkages and the presence of two dihydroflavonols and three glycosylated alkaloids were determined for the first time. The proanthocyanidin, flavonoid, amino acid, and total compound contents were quantified, revealing decreases in their levels during maturation as well as a polymerization process formation of polymers from monomers during seed maturation. Interestingly, glycosylated alkaloids were only detected in seed cotyledons being highest at green–brown stage, whereas proanthocyanidins were present at a concentration of 8,226.19 ± 249.96 μg/g (dry weight) in green–brown stage of seed coats. Our findings may provide insights into the utilization of lotus seeds as a functional food.

Lead and Cadmium Tolerance and Accumulation of Proanthocyanidin-Deficient mutants of the Fern Athyrium yokoscense

The fern Athyrium yokoscense often flourishes around mine sites in Japan and can tolerate and accumulate heavy metals such as lead (Pb) and cadmium (Cd). In this work, we examined whether proanthocyanidins, also called condensed tannins, were involved in the mechanisms of Pb and Cd tolerance and accumulation of A. yokoscense because proanthocyanidins are known to alleviate metal stress in several plant species and are present at high levels in A. yokoscense. For this purpose, we used mutant gametophytes deficient in proanthocyanidins, in which the relative proanthocyanidin contents were 20% of those of the wild-type gametophytes. Although the proanthocyanidin contents of the mutant were quite low, the growth of the mutant was very similar to that of the wild-type gametophytes even in the presence of 80 mg/kg Pb or 48 mg/kg Cd. Under the same conditions, the mutant gametophytes also accumulated Pb and Cd as much as the wild-type gametophytes did. These results indicate that the proanthocyanidins in A. yokoscense are not important for the Pb and Cd tolerance and accumulation properties.

Profile of fatty acids, vitamins, phytosterols and phenolic acids in Trachystemon orientalis L. and evaluation of their antioxidant activity

The present study focuses on the phytochemical content and antiradical properties of Trachystemon orientalis L., which grows spontaneously and is consumed as food in rural areas of Düzce (from Turkey) province. DPPH, ABTS and OH radical scavenging tests were utilized for identifying the antiradical properties of the extracts of this plant. In addition, the metal chelating potential of this plant was also evaluated. The higher the inhibition % value calculated in these tests, the higher the antioxidant activity was considered and the results were evaluated. T. orientalis the average ABTS radical cleaning test results of extracts prepared in different concentrations of methanol, ethanol and purified water were found to be 93.35%, 91.32%, 94.70%, respectively. The average DPPH radical cleaning test results of the extracts of this plant prepared in different concentrations of methanol, ethanol and purified water were determined as 37.26%, 7.95%, 52.26%, respectively. T. orientalis the OH radical cleaning test results of the extracts of plant prepared from methanol, ethanol and purified water were determined as 60.85%, 61.33%, 24.12%, respectively. In addition, the metal chelation test results of methanol, ethanol and pure water extracts of this plant were found to be 63.57%, 42.04%, 82.64%. It was determined that the highest content of protein (20.93 mgBSA/g), proanthocyanidin (13.76 µg CE/g) and phenolic (3621.03 µg GAE/g) was found in T. orientalis pure water extract. It has been determined that gallic acid (187.67 μg/g), vanillic acid (3.78 μg/g), rosmarinic acid (10.55 μg/g) and hydrocynamic acid (0.78 μg/g) are found in different proportions in T. orientalis plant. It has been observed that T. orientalis is an important source of palmitic acid, stearic acid, oleic acid, linoleic acid, γ-linolenic acid, alpha-linolenic acid, gadoleic acid and docosahexaenoic acid. It has been established that this plant has a low content of fat-soluble vitamins and phytosterols.

Grafting with rootstocks promotes phenolic compound accumulation in grape berry skin during development based on integrative multi-omics analysis.

In viticulture, grafting has been practiced widely and influences grape development as well as berry and wine quality. However, there is limited understanding of the effects of rootstocks on grape phenolic compounds, which are located primarily in the berry skin and contribute to certain sensory attributes of wine. In this study, scion–rootstock interactions were investigated at the green-berry stage and the veraison stage when grapevines were hetero-grafted with three commonly used rootstock genotypes (5BB, 101-14MG, and SO4). Physiological investigations showed that hetero-grafts, especially CS/5BB, contained higher concentrations of total proanthocyanidins (PAs) and various PA components in berry skins compared with the auto-grafted grapevines. Further metabolomics analysis identified 105 differentially accumulated flavonoid compounds, the majority of which, including anthocyanins, PAs, and flavonols, were significantly increased in the berry skins of hetero-grafted grapevines compared with auto-grafted controls. In addition, transcriptomic analysis of the same samples identified several thousand differentially expressed genes between hetero-grafted and auto-grafted vines. The three rootstocks not only increased the transcript levels of stilbene, anthocyanin, PA, and flavonol synthesis genes but also affected the expression of numerous transcription factor genes. Taken together, our results suggest that hetero-grafting can promote phenolic compound accumulation in grape berry skin during development. These findings provide new insights for improving the application value of grafting by enhancing the accumulation of nutritious phenolic components in grape.

Effects of foliar iron spraying on Cabernet Sauvignon phenolic acids and proanthocyanidins

In order to explore the effect of different irons on the fruit quality of wine grapes, as well as the phenolic acids and proanthocyanidins of the peel, “Cabernet Sauvignon” was taken as the research object. Ferrous sulfate, EDTA-Fe, ferric citrate, ferric gluconate and ferric sugar alcohol were sprayed between the coloring periods, and the foliar sprayed water was used as the control. The results showed that foliar spraying of iron would increase the fruit sugar-acid ratio and 100-grain weight; iron spraying would up-regulate the content of phenolic acid monomers, among which EDTA-Fe and ferric citrate had significant up-regulating effects, but all iron treatments had a significant effect on the increase. The content of caffeic acid and chlorogenic acid was down-regulated; the content of proanthocyanidin monomer was up-regulated by iron spraying, and the content of proanthocyanidin monomer was significantly up-regulated by ferric citrate treatment. Foliar spraying of ferric citrate not only balanced the sugar-acid ratio of the fruit, but also increased the content of phenolic acid and proanthocyanidin in the grape peel, which further improved the quality of the grapes and helped to increase the flavor of the wine.