High Levels Of Flavonols Research Articles

A comparative UPLC-orbitrap-MS-based metabolite profiling of three Pelargonium species cultivated in Egypt

Several Pelargonium species are cultivated mainly to produce essential oils used in perfume industry and for ornamental purposes. Although the chemical composition and biological activities of their essential oils were extensively investigated, there is limited information about the chemical composition of their non-volatile constituents. In this study, we report an Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS)-based metabolomics approach for the annotation and analysis of various metabolites in three species; P. graveolens, P. denticulatum, and P. fragrans utilizing The Global Natural Product Social Molecular Networking (GNPS) and multivariate data analyses for clustering of the metabolites. A total of 154 metabolites belonging to different classes were annotated. The three species are good sources of coumarins, benzoic acid derivatives, organic acids, fatty acids, and phospholipids. However, the highest level of flavonols (mono- and di-O-glycosides) and cinnamic acid derivatives was found in P. graveolens and P. denticulatum, whereas tannins and flavone C-glycosides were abundant in P. fragrans. The metabolic profiles clarified here provide comprehensive information on the non-volatile constituents of the three Pelargonium species and can be employed for their authentication and possible therapeutic applications.

BIOLOGICALLY ACTIVE COMPOUNDS AND ANTIOXIDANT ACTIVITY OF THE PLANTS FROM THE MOUN-TAIN ALTAI OF THE CARAGANA GENUS

The article presents Data on the content of biologically active compounds (BAC) and the total phenolic antioxidants activity (TPA) evaluated for aboveground organs of three species from the Caragana Genus – C. bungei, C. pygmaea и C. spinosa, growing in the Mountain Altai. It was determined that leaves and reproductive organs contain flavonols, catechins, tannins, carotenoids, pectin substances. It is shown that biologically active substances of a plant are synthesized differently depending on the species, habitat and organ of the plant. The highest level of flavonols (36.4 мг/г), tannins (117.2 мг/г) and carotenoids (0.56 мг/г) was registered in leaves of C. spinosa. Catechins predominantly accumulated in the leaves of C. pygmaea (up to 211.3 mg/100g) and inflorescences of C. bungei (up to 205 mg/g). The content of pectin substances was quite high, with the biggest share of protopectins. The highest level of protopectins was registered in inflorescences of C. bungei (5.81%) and leaves of C. pygmaea (3.58%). Pectins are synthesized more in the flowers of C. bungei (0.74%) and leaves of C. spinosa (0.49%). The highest values of antioxidant activity were found in the water–ethanol extracts from the leaves of C. spinosa (1.61 mg/g), which is probably due to the increased content of flavonols and tannins. It was shown that the antioxidant activity of Caragana plants is 71% determined by the content of tannins, 62% by the content of flavonols and 41% by the content of carotenoids. C. spinosa is more promising for finding sources of antioxidants.

Biosynthesis and Chemopreventive Potential of Jute (Corchorus capsularis and C. olitorius) Flavonoids and Phylogeny of Flavonoid Biosynthesis Pathways

AbstractFlavonoids are valuable phytochemicals for human health and nutrition. Jute (Corchorus capsularis and C. olitorius), a vegetable rich in phenolics and flavonoids, is globally consumed for its health benefit, but the biosynthesis pathways and metabolic profiles of its flavonoids are poorly characterized. Elucidating the flavonoid biosynthesis pathways would augment the broader use of jute, including targeted synthesis of its specific flavonoids. We reconstructed the core flavonoid biosynthesis pathways in jute by integrating transcriptome mining, HPLC and flavonoid histochemistry. In C. capsularis (white jute), the flavonoid biosynthesis pathways’ metabolic flux was driven toward the biosynthesis of proanthocyanidins that mediate the acquisition of abiotic stress tolerance. However, higher levels of flavonols in C. olitorius (tossa jute) render it more suitable for nutritional and medicinal use. Jute flavonoid extract exhibited in vitro inhibition of matrix metalloproteinase-2, suggesting its potential chemopreventive and immunity-boosting roles. Using the flavonoid biosynthesis pathways profiles of 93 plant species, we reconstructed the flavonoid biosynthesis pathways phylogeny based on distance-based clustering of reaction paths. This reaction-path flavonoid biosynthesis pathways phylogeny was quite distinct from that reconstructed using individual gene sequences. Our flavonoid biosynthesis pathways-based classification of flavonoid groups corroborates well with their chemical evolution, suggesting complex, adaptive evolution of flavonoid biosynthesis pathways, particularly in higher plants.

Biologically Active Compounds and Antioxidant Activity of the Plants from CSBG SB RAS Collection of the Rosaceae Family (I)

The article presents Dara on the content of biologically active compounds (BAC) and the total phenolic antioxidants activity (TPA) evaluated for leaves and inflorescences of eight species from the Rosaceae family: Padus avium, Malus baccata, Alhemilla vulgaris, Potentilla inquinans, Filipendula vulgaris, F. palmata, Sanguisorba officinalis, S. alpina. It was determined that leaves and inflorescences contain flavonols, catechins, tannins, carotenoids, saponins, pectin substances. Usually, woody plants tend to accumulate less BAC and TPA than herbs. The highest level of flavonols and tannins was registered in inflorescences of F. vulgaris (12.25% and 45.02 %). The content of pectin substances was quite high, with the biggest share of protopectins (4.4-10.65%). The maximum quantity of catechins (4.76%) was found in the leaves of F. palmata, saponins – in the inflorescences of M. baccata (20.77%). The highest content of carotenoids was found in the leaves of plants, most notably in P. inquinans (1.00 mg/g). The highest antioxidant activity was recorded for water-ethanol extracts from inflorescences (up to 7.77 mg/g) and leaves (2.11 mg/g) of F. vulgaris and A. vulgaris plants due to increased content of phenolic compounds, in particular flavonols and tannins, compared to the other species.

White versus blue: Does the wild ‘albino’ bilberry (Vaccinium myrtillus L.) differ in fruit quality compared to the blue one?

Wild albino and blue bilberry fruit were analyzed to compare different fruit characteristics linked to the composition of primary and secondary metabolites. Compounds were identified using HPLC–MS and standard quality parameters were determined. Albino berries were significantly smaller, accumulated less water and were characterized by 23% higher dry weight. Soluble solids content and pH value were higher in albino bilberry and their surface was lighter and characterized by a yellow hue. Both bilberry forms accumulated identical individual sugars and organic acids; however, the albino form had 33% higher content of total sugars and 9% higher content of total organic acids compared to the blue type. Fifteen anthocyanins were identified in both forms, but in albino bilberries, individual anthocyanins were only detected in traces. Blue bilberry contained 1.6-fold higher levels of flavanols, 2.1-fold higher levels of flavonols, 2.5-fold higher levels of hydroxycinnamic acid derivatives and consequently, 4.6-fold higher total phenolic content.

Vplyv podmienok pestovania na akumul�ciu flavonolov a antoky�nov v zelenom a cervenom �al�te

The aim of the study was to investigate the effect of different growth conditions on anthocyanins and flavonols accumulation in leaves of green and red loose leaf lettuce (Lactuca sativa var. crispa). Lettuce plants were grown in three types of conditions, in greenhouse (I. variant), behind clear glass in field (II. variant) and in open field conditions (III. variant). Estimation of anthocyanins and flavonols content was done by non-destructive measurements with optical fluorescence sensor Multiplex® 3 (Force-A, France). It was estimated that green lettuce varieties had a greater flavonols content compared to red lettuce varieties in all experimental variants. The highest level of flavonols was detected in leaves of green variety Zoltán (1.218 RU) and in red lettuce had the highest amount of flavonols in variety Carmesi (1.095 RU). At the same time red lettuce varieties were characterized by higher anthocyanins content. Parameter anthocyanin index is correlated with visible red coloration of leaves. The highest content of anthocyanins was detected in variety Oakly (0.867 RU). Under the open field conditions was found statistically significant higher (P < 0.05) flavonols and anthocyanins level in both green and red lettuce leaves compared to greenhouse conditions. It may be connected with intensification of flavonoids biosynthesis and accumulation which normally stimulated by sun irradiation, especially UV-B radiation.

Profiling of primary metabolites and flavonols in leaves of two table grape varieties collected from semiarid and temperate regions

Cultivation of grapes in West Bank – Palestine is very old and a large number of grape varieties exist as a result of continuous domestication over thousands of years. This rich biodiversity has highly influenced the consumer behavior of local people, who consume both grape berries and leaves. However, studies that address the contents of health-promoting metabolites in leaves are scarce. Accordingly the aim of this study is to assess metabolite levels in leaves of two grape varieties that were collected from semiarid and temperate regions. Metabolic profiling was conducted using GC–MS and LC–MS. The obtained results show that abiotic stresses in the semiarid region led to clear changes in primary metabolites, in particular in amino acids, which exist at very high levels. By contrast, qualitative and genotype-dependent differences in secondary metabolites were observed, whereas abiotic stresses appear to have negligible effect on the content of these metabolites. The qualitative difference in the flavonol profiles between the two genotypes is most probably related to differential expression of specific genes, in particular flavonol 3-O-rhamnosyltransferase, flavonol-3-O-glycoside pentosyltransferases and flavonol-3-O-d-glucosidel-rhamnosyltransferase by ‘Beituni’ grape leaves, which led to much higher levels of flavonols with rutinoside, pentoside, and rhamnoside moieties with this genotype.

Negative Regulation of Anthocyanin Biosynthesis in Arabidopsis by a miR156-Targeted SPL Transcription Factor

Flavonoids are synthesized through an important metabolic pathway that leads to the production of diverse secondary metabolites, including anthocyanins, flavonols, flavones, and proanthocyanidins. Anthocyanins and flavonols are derived from Phe and share common precursors, dihydroflavonols, which are substrates for both flavonol synthase and dihydroflavonol 4-reductase. In the stems of Arabidopsis thaliana, anthocyanins accumulate in an acropetal manner, with the highest level at the junction between rosette and stem. We show here that this accumulation pattern is under the regulation of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, which are deeply conserved and known to have important roles in regulating phase change and flowering. Increased miR156 activity promotes accumulation of anthocyanins, whereas reduced miR156 activity results in high levels of flavonols. We further provide evidence that at least one of the miR156 targets, SPL9, negatively regulates anthocyanin accumulation by directly preventing expression of anthocyanin biosynthetic genes through destabilization of a MYB-bHLH-WD40 transcriptional activation complex. Our results reveal a direct link between the transition to flowering and secondary metabolism and provide a potential target for manipulation of anthocyanin and flavonol content in plants.

Modulation of flavonoid biosynthetic pathway genes and anthocyanins due to virus infection in grapevine (Vitis viniferaL.) leaves

BackgroundSymptoms of grapevine leafroll disease (GLRD) in red-fruited wine grape (Vitis vinifera L.) cultivars consist of green veins and red and reddish-purple discoloration of inter-veinal areas of leaves. The reddish-purple color of symptomatic leaves may be due to the accumulation of anthocyanins and could reflect an up-regulation of genes involved in their biosynthesis.ResultsWe examined six putative constitutively expressed genes, Ubiquitin, Actin, GAPDH, EF1-a, SAND and NAD5, for their potential as references for normalization of gene expression in reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). Using the geNorm program, a combination of two genes (Actin and NAD5) was identified as the stable set of reference genes for normalization of gene expression data obtained from grapevine leaves. By using gene-specific RT-qPCR in combination with a reliable normalization factor, we compared relative expression of the flavonoid biosynthetic pathway genes between leaves infected with Grapevine leafroll-associated virus 3 (GLRaV-3) and exhibiting GLRD symptoms and virus-free green leaves obtained from a red-fruited wine grape cultivar (cv. Merlot). The expression levels of these different genes ranged from two- to fifty-fold increase in virus-infected leaves. Among them, CHS3, F3'5'H, F3H1, LDOX, LAR1 and MybA1 showed greater than 10-fold increase suggesting that they were expressed at significantly higher levels in virus-infected symptomatic leaves. HPLC profiling of anthocyanins extracted from leaves indicated the presence of cyanidin-3-glucoside and malvidin-3-glucoside only in virus-infected symptomatic leaves. The results also showed 24% higher levels of flavonols in virus-infected symptomatic leaves than in virus-free green leaves, with quercetin followed by myricetin being the predominant compounds. Proanthocyanidins, estimated as total tannins by protein precipitation method, were 36% higher in virus-infected symptomatic leaves when compared to virus-free green leaves.ConclusionsThe results, the first example to our knowledge, showed that modulation of the flavonoid biosynthetic pathway occurred in GLRaV-3-infected leaves of a red-fruited wine grape cultivar (cv. Merlot) leading to de novo synthesis of two classes of anthocyanins. These anthocyanins have contributed to the expression of reddish-purple color of virus-infected grapevine leaves exhibiting GLRD symptoms.

White and green tea polyphenols inhibit pancreatic lipase in vitro

Abstract Green, white and black teas were assayed for inhibition of pancreatic lipase activity in vitro. White tea proved to be more effective than green tea with black tea showing little inhibition even at 200 μg GAE/ml. The EC50 values for inhibition were 22 μg/ml for white tea and 35 μg/ml for green tea; both easily achievable from normal infusions of tea. Liquid chromatography-mass spectroscopy analysis showed that white and green teas had essentially equal amounts of flavan-3-ols but green tea had higher levels of flavonols. White tea had higher levels of 5-galloyl quinic acid, digalloyl glucose, trigalloyl glucose and the tannin, strictinin. After chromatography on Sephadex LH-20, the main inhibitory fraction was enriched in strictinin and fractions enriched in other components were ineffective. This suggests that strictinin content may be crucial for inhibition of pancreatic lipase. However, the possibility of synergies between the polyphenols cannot be disregarded.

Phenolic compounds and antioxidant activity of extracts of Ginkgo leaves

AbstractThe aim of the present study was to determine the flavonol contents of crude extracts from Ginkgo (Ginkgo biloba L.) leaves, their antioxidant properties in model system studies, and their inhibitory action of linoleic acid oxidation in an emulsion system and of triacylglycerols (TAG) in rapeseed oil. Extracts were prepared from both green and yellow leaves of Ginkgo trees using water, aqueous acetone, and ethanol. Extracts were analyzed by HPLC for their presence and content of selected flavonols; these included myricetin, quercetin, kaempferol, isorhamnetin, and morin. The highest level of flavonols, especially quercetin, myricetin and kaempferol, were found in the aqueous acetonic extracts. Crude extracts from yellow Ginkgo leaves contained greater amounts of flavonols. The best DPPH radical‐scavenging activity amongst the Ginkgo extracts examined was determined for aqueous acetonic extracts, while the lowest was noted for the ethanolic extract of green leaves. Water infusion extracts exhibited the highest iron(II) chelating activity. The reducing power of extracts from yellow leaves was 2 higher than that of crude extracts from green leaves. Nevertheless, extracts from green Ginkgo leaves imparted a greater protection factor against TAG oxidation, as assessed by the Rancimat method. Crude extracts from yellow Ginkgo leaves were more efficacious than green ones at inhibiting oxidation of the linoleic acid emulsion.

Bioactive Compounds of Selected Fruit Juices

Fruits are one of the most important sources of phenolic compounds in our diet. Many of these compounds exhibit a wide range of biological activities, especially antioxidant activity. The objective of this study was to determine the composition and antioxidant activity of phenolic compounds found in fruit juice obtained from buckthorn, flowering quince, rowanberry and hawthorn. Hydroxycinnamic acids (neochlorogenic and chlorogenic acid) and procyanidins were the main phenolics in rowanberry juice. The highest level of flavonols (quercetin derivatives) was found in sea buckthorn. All juices showed strong free-radical scavenging activity against ABTS*+ radicals and ferric reducing ability measured by the FRAP method. The strongest antioxidant activity was found in rowanberry juice, but the lowest was measured in hawthorn and sea buckthorn juices.

AtMYB12 regulates caffeoyl quinic acid and flavonol synthesis in tomato: expression in fruit results in very high levels of both types of polyphenol

Plant polyphenolics exhibit a broad spectrum of health-promoting effects when consumed as part of the diet, and there is considerable interest in enhancing the levels of these bioactive molecules in plants used as foods. AtMYB12 was originally identified as a flavonol-specific transcriptional activator in Arabidopsis thaliana, and this has been confirmed by ectopic expression in tobacco. AtMYB12 is able to induce the expression of additional target genes in tobacco, leading to the accumulation of very high levels of flavonols. When expressed in a tissue-specific manner in tomato, AtMYB12 activates the caffeoyl quinic acid biosynthetic pathway, in addition to the flavonol biosynthetic pathway, an activity which probably mirrors that of the orthologous MYB12-like protein in tomato. As a result of its broad specificity for transcriptional activation in tomato, AtMYB12 can be used to produce fruit with extremely high levels of multiple polyphenolic anti-oxidants. Our data indicate that transcription factors may have different specificities for target genes in different plants, which is of significance when designing strategies to improve metabolite accumulation and the anti-oxidant capacity of foods.

Flavonols (kaempeferol, quercetin, myricetin) contents of selected fruits, vegetables and medicinal plants

The concentrations of flavonols (kaempeferol, quercetin, myricetin) were determined in 22 plant materials (9 vegetables, 5 fruits, and 8 medicinal plant organs). The materials were extracted with acidified methanol (methanol/HCl, 100:1, v/v) and analyzed by reverse phase high-performance liquid chromatographic (RP-HPLC) with UV detection. The total flavonols contents varied significantly (P<0.05) among vegetables, fruits and medicinal plant organs ranged from 0 to 1720.5, 459.9 to 3575.4, and 2.42 to 6125.6mgkg−1 of dry matter, respectively. Among vegetables, spinach and cauliflower exhibited the highest amounts of flavonols (1720.5 and 1603.9mgkg−1, respectively), however, no flavonols were detected in garlic. Within fruits, highest level of flavonols was observed in strawberry (3575.4mgkg−1), whereas, the lowest in apple fruit (459.9mgkg−1). Of the medicinal plant organs, moringa and aloe vera leaves contained the highest contents of flavonols (6125.6 and 1636.04mgkg−1), respectively, whereas, lowest was present in barks (2.42–274.07mgkg−1). Overall, leafy green vegetables, soft fruits and medicinal plant leaves exhibited higher levels of flavonols.

Phenolic Antioxidants (Hydrolyzable Tannins, Flavonols, and Anthocyanins) Identified by LC-ESI-MS and MALDI-QIT-TOF MS from Rosa chinensis Flowers

Rosa chinensis (Yuejihua) is a well-known ornamental plant, and its flowers are commonly used in traditional Chinese medicine. Methanolic crude extracts of dried R. chinensis flowers were used for simultaneous determination of phenolic constituents by liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS). A total of 36 known and unknown phenolics were identified as hydrolyzable tannins, flavonols, and anthocyanins, mainly including gallotannins (mono-, di-, or trigalloylglucopyranosides), ellagitannins, quercetin, quercetin/kaempferol mono- and diglycosides, and cyanidin/pelargonidin diglycosides. MALDI-QIT-TOF MS was applied not only to verify most phenolics isolated and identified by LC-MS but also to tentatively identify two ellagitannins (rugosins B and C) not isolated and unidentified by LC-MS. This study is the first to demonstrate the rapid and successful use of MALDI-QIT-TOF MS and LC-MS to directly and simultaneously identify phenolics in the crude extracts of R. chinensis flowers without any purification. The antioxidant activity of the crude extracts from R. chinensis flowers was also measured with three assay methods. The results showed that the phenolic antioxidants from R. chinensis flowers exhibited very strong radical scavenging effect and antioxidant power. High levels of flavonols and hydrolyzable tannins might be important bioactive principles in the dried R. chinensis flowers.

Flavonols are not essential for fertilization in Arabidopsis thaliana.

Flavonols are plant metabolites suggested to serve a vital role in fertilization of higher plants. Petunia and maize plants mutated in their flavonol biosynthesis are not able to set seed after self-pollination. We have investigated the role of these compounds in Arabidopsis thaliana. Like in all other plant species, high levels of flavonols could be detected in pollen of wild-type A. thaliana. No flavonols were detected in reproductive organs of the A. thaliana tt4 mutant in which the chs gene is mutated. Surprisingly, this mutant did set seed after self-fertilization and no pollen tube growth aberrations were observed in vivo. The role of flavonols during fertilization of Arabidopsis is discussed.