C-glycosyl Flavones Research Articles

Vitexin inhibits acrylamide-induced neuroinflammation and improves behavioral changes in zebrafish larvae

Neuroinflammation is crucial for the pathophysiological hallmarks of many neurodegenerative disorders. Hyperactivated microglia has long been implicated as a detrimental player in regulating unresolvable inflammatory insults which cause damage to neurons. In the context of acrylamide (ACR) neurotoxicity, microglia activation is documented to correlate with ACR-adduct formation in the presynaptic neurons. Thus, inhibition of inflammatory mediators through vital candidate is greatly warranted to retard the disease progression. In the present study, we investigated, whether vitexin, a C-glycosylated flavone, with anti-inflammatory activity, could inhibit ACR-induced neuroinflammation-like behavior in zebrafish larvae. ACR was exposed at a dose 1 mM to 3 days post fertilization (dpf) zebrafish larvae for 3 days, whereas vitexin (10 μM) was treated for 24 h. After vitexin treatment, a series of histopathology, behavioral tests and molecular analyses were measured. Our data show that ACR larvae exhibited abnormal morphologies in brain cartilage and histological patterns. At behavioral levels, motor function was altered while the expression of pro-inflammatory mediator levels was markedly up-regulated in ACR larvae. Further, we validated the enhanced CDK5 activity is known to trigger microglia activation, also we found reduced expressions of neuroplasticity (CREB1 and ATF1) and antioxidant response makers (Nrf2, SOD-1 and CAT) in ACR intoxicated larvae. Interestingly, vitexin treatment markedly alleviated ACR-induced histological and behavioral changes in zebrafish larvae. Moreover, vitexin effectively inhibited CDK5 expression, and also hampered the release of pro-inflammatory mediators in ACR larvae. Finally, vitexin treatment rescued the loss of neuroplasticity markers along with enhanced antioxidant markers in ACR larvae. Taken together, results in the present study showed the possibility of vitexin as a potential therapeutic drug in the suppression of neuroinflammation.

C-/O-GLYCOSYL FLAVONES OF SILENE ITALICA

Chemical research of Silene genus focused on the study of terpene compounds including ecdysteroids and triterpenoids, to the detriment of other classes of compounds. One of these poorly estimated group of substances are flavonoids, namely C-/O-glycosyl flavones, widely represented within the family Caryophyllaceae. Early studies revealed the presence of some C-glycosyl flavones (Zemtsova, Dzhumyrko, 1976; Darmogray, 1977), but a detailed study of the flavonoids was not conducted. Application of high performance chromatography with diode-array detection and electrospray ionization mass-spectrometry detection (HPLC-DAD-ESI-MS) allowed to found 14 flavonoids, which are C-, O- and C,O-glycosyl flavones in the aerial part of S. italica of Georgia origin. Ten components were discovered in S. italica for first time. The identified C-glycosides included monoglycosides as isoorientin, isovitexin, isoscoparin (chrysoeryol-6-C-glucoside) and diglycosides as carlinoside (luteolin-6-C-glucoside-8-C-arabinoside), schaftoside (apigenin-6-C-glucoside-8-C-arabinoside), isoschaftoside (luteolin-6-C-arabinoside-8-C-glucoside) and genkwanin-6-C-glucoside-8-C-arabinoside. Two O-glycosides, cosmosiin and cynaroside, and mixed C,O-glycosides as saponarin, isovitexin-2′′-O-arabinoside, isovitexin-6′′-O-arabinoside and O-hexosides od schaftosude and genkwanin-6-C-glucoside- 8-C-arabinoside were not previously identified in Silene genus. The known literature data (Mamadalieva et al., 2014) and the present data demonstrate the useful role of C-/O-glycosyl flavones in the systematics of the genus Silene.

Bacillus velezensis YC7010 Enhances Plant Defenses Against Brown Planthopper Through Transcriptomic and Metabolic Changes in Rice.

Brown planthopper (BPH; Nilaparvata lugens Stål) is one of the most serious insect pests, which reduce rice yield remarkably in many rice-growing areas. A few plant growth-promoting rhizobacteria induce systemic resistance against herbivorous insects. Here we show that root drenching of rice seedlings with an endophytic strain Bacillus velezensis YC7010 enhanced defenses against BPH. Based on high-throughput transcriptome analysis, systemic resistance against BPH was induced by B. velezensis YC7010 via salicylic acid (SA)- and jasmonic acid (JA)-dependent pathways. Increased leaf contents of secondary metabolites, tricin and C-glycosyl flavone and cell-wall contents of lignin and cellulose were the key defense mechanisms inducing resistance against BPH during the three-way interaction. This study shows for the first time that chemical changes and strengthening of physical barriers play important roles simultaneously in plant defense against BPH in rice by the endophytic bacteria. This defense was induced by lipopeptides including a novel bacillopeptin X.

Rapid discovery and global characterization of multiple components in corn silk using a multivariate data processing approach based on UHPLC coupled with electrospray ionization/quadrupole time-of-flight mass spectrometry.

Corn silk is an important traditional Chinese medicine which has been widely used as diuretic, antilithiasic, uricosuric, antiseptic, etc. for thousands of years. However, it is a pity that the chemical ingredients in corn silk, especially the constituents absorbed into blood, are unclear up to now. The aim of our study was to investigate the multiple components of corn silk in vitro and in vivo. In this present study, a sensitive and rapid method using ultra high performance liquid chromatography coupled with electrospray ionization/quadrupole time-of-flight tandem mass spectrometry and a multivariate data processing approach was established to detect the constituents of corn silk in vitro and in vivo. Consequently, total 41 ingredients in vitro and 19 of them absorbed into blood including luteolin, various C-glycosyl flavones, jasmonic acid, abscisic acid, gibberellin A, etc. were tentatively characterized in sequence. Furthermore, of particular importance, a kind of stable compound named C-glycosyl flavones is a great discovery in vivo, which can point the further pharmacological study target in future. In a word, this is the first serum pharmacochemistry study of corn silk, which played a critical role in exploring the pharmacological and effective data for further research.

Unique Flavanol-Anthocyanin Condensed Forms in Apache Red Purple Corn

Anthocyanin pigments from purple corn are being explored as a potential alternative to artificial colorants and for their health-promoting properties. However, all pericarp-pigmented corn varieties examined to date primarily contain cyanidin-derived anthocyanins, which produce bluish-red or pink extracts. Here we describe the first pelargonidin-dominant pericarp-pigmented corn lines from the landrace Apache Red (AR). Anthocyanins were characterized from six AR families using high-performance liquid chromatography-mass spectrometry (HPLC-MS). From this, we identified two new flavanol-anthocyanin condensed forms in corn: catechin-(4,8)-pelargonidin 3,5-diglucoside and afzelechin-(4,8)-pelargonidin 3,5-diglucoside, which were subsequently confirmed with NMR. Additionally, several apigenin-derived C-glycosyl flavones were identified in abundance. With a diverse flavonoid profile containing an array of different anthocyanin species and flavones, Apache Red will be an important line in which to study control of the flavonoid biosynthesis pathway.

Indirect and direct routes to C-glycosylated flavones in Saccharomyces cerevisiae

BackgroundC-glycosylated flavones have recently attracted increased attention due to their possible benefits in human health. These biologically active compounds are part of the human diet, and the C-linkage makes them more resistant to hydrolysis and degradation than O-glycosides. In contrast to O-glycosyltransferases, few C-glycosyltransferases (CGTs) have so far been characterized. Two different biosynthetic routes for C-glycosylated flavones have been identified in plants. Depending on the type of C-glycosyltransferase, flavones can be glycosylated either directly or indirectly via C-glycosylation of a 2-hydroxyflavanone intermediate formed by a flavanone 2-hydroxylase (F2H).ResultsIn this study, we reconstructed the pathways in the yeast Saccharomyces cerevisiae, to produce some relevant CGT substrates, either the flavanones naringenin and eriodictyol or the flavones apigenin and luteolin. We then demonstrated two-step indirect glycosylation using combinations of F2H and CGT, to convert 2-hydroxyflavanone intermediates into the 6C-glucoside flavones isovitexin and isoorientin, and the 8C-glucoside flavones vitexin and orientin. Furthermore, we established direct glycosylation of flavones using the recently identified GtUF6CGT1 from Gentiana triflora. The ratio between 6C and 8C glycosylation depended on the CGT used. The indirect route resulted in mixtures, similar to what has been reported for in vitro experiments. In this case, hydroxylation at the flavonoid 3′-position shifted the ratio towards the 8C-glucosylated orientin. The direct flavone glycosylation by GtUF6CGT1, on the other hand, resulted exclusively in 6C-glucosides.ConclusionsThe current study features yeast as a promising host for production of flavone C-glycosides, and it provides a set of tools and strains for identifying and studying CGTs and their mechanisms of C-glycosylation.

Chemical characterization with in vitro biological activities of Gypsophila species

Methanol-aqueous extracts from the aerial parts of Gypsophila glomerata (GGE), G. trichotoma (GTE) and G. perfoliata (GPE) were investigated for antioxidant potential using different in vitro models, as well as for phenolic and flavonoid contents. The possible anti-cholinesterase, anti-tyrosinase, anti-amylase and anti-glucosidase activities were also tested. The flavonoid variability was analyzed using ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadrupole-Orbitrap high resolution mass spectrometry (HRMS). Eleven C-glycosyl flavones and 4 O-glycosyl flavonoids, including 2”-O-pentosyl-6-C-hexosyl-apigenin/methylluteolin, as well as their mono(di)-acetyl derivatives were found in GGE. Both GGE and GTE shared 2”-pentosyl-6-C-hexosyl-luteolin together with the common saponarin, homoorientin, orientin, isovitexin and vitexin, while di C-glycosyl flavones were evidenced only in GPE.The highest radical scavenging in both ABTS and DPPH assays was noted in GPE, as well as ferric and cupric reducing abilities. However, GTE had the strongest metal chelating activity (17.44 ± 0.51 mg EDTAE/g extract). GPE and GGE were more potent as acetylcholinesterases inhibitors witnessed by 2.09 ± 0.02 mg GALAE/g extract and 1.59 ± 0.09 mgGALAE/g extract, respectively. All flavonoids were found in G. glomerata for the first time. Therefore, further isolation and structural elucidation of newly described acetylated flavonoids are needed in order to determine their relevance in the beneficial properties of the plant.

Flavonoid accumulation in common buckwheat (Fagopyrum esculentum) sprout tissues in response to light

The content and accumulation patterns of flavonoids in response to light were investigated in common buckwheat (Fagopyrum esculentum) sprouts over the course of 9 days. Buckwheat sprouts were grown under fluorescent (FL), red (RL), and blue (BL) light sources, as well as in darkness, and their extracts were analyzed. Sprout elongation and chlorophyll content were high in the presence of red light. The contents of the major buckwheat sprout flavonoids, orientin, isoorientin, vetexin, isovetexin, and rutin all peaked 5 days after germination under all four growth conditions, then gradually decreased. Sprouting cotyledons accumulated around 1.5-fold more orientin, isoorientin, quercetin-3-O-robinobioside, and rutin in the presence of red light, including from the RL and FL light sources, than in blue light alone. The C-glycosyl flavones, orientin, isoorientin, vetexin, and isovetexin, were not detected in the stem tissues of the hypocotyls, but C-glycosyl flavonols, such as quercetin-3-O-robinobioside and rutin, were present, and were twice as abundant under BL and FL than in the RL and darkness conditions. In the root tissues, a small amount of C-glycosyl flavonols was detected after BL exposure only; however, the other flavonoids were not detected at all. These results indicated that red light induces flavonoid biosynthesis in the cotyledons of buckwheat seedlings, but blue light has a greater effect on the accumulation of C-glycosyl flavonols in other seedling tissues.

C-glycosyl flavone from Urginea indica inhibits proliferation & angiogenesis & induces apoptosis via cyclin-dependent kinase 6 in human breast, hepatic & colon cancer cell lines.

Background & objectives:Search for novel compounds beneficial to the treatment of cancer attracts a great deal of attention. We earlier demonstrated the isolation of 5,7-dihydroxy-2-[4’-hydroxy-3’-(methoxymethyl)phenyl]-6-C-β-glucopyranosyl flavone, a novel C-glycosyl flavone from Urginea indica bulb. The present study was undertaken to investigate the effect of this novel compound on human normal epithelial and breast, hepatic and colon cancer cell lines.Methods:The maximum non-toxic concentration (MNTC) and cytotoxicity of C-glycosyl flavone were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Cell cycle was analyzed by flow cytometry. Docking studies were performed to predict possible targets. Levels of cyclin-dependent kinase 1 (CDK1) and CDK6, Bcl2 and BAX and cytochrome c were quantified by specific ELISA. Mitochondrial membrane potential was determined using JC-1 dye. Apoptosis was quantified by Annexin V ELISA method.Results:Flow cytometry analysis demonstrated G0/G1 arrest. In silico docking studies predicted CDK1 and CDK6 as a possible target of C-glycosyl flavone. In vitro study confirmed CDK6 as the main target in C-glycosyl flavone-treated cancer cell lines. C-glycosyl flavone treatment also induced membrane blebbing, chromatin fragmentation and nucleosome formation. C-glycosyl flavone treatment caused marked loss of mitochondrial membrane potential, decrease in Bcl2/BAX ratio and activation of caspase-3 and release of caspase-9 and cytochrome c. In addition, C-glycosyl flavone inhibited the tumour-induced angiogenesis and reduced the vascular endothelial growth factor levels. Similarly, CDK6 inhibitor significantly inhibited proliferation and angiogenesis and induced apoptosis in tested cell lines.Interpretation & conclusions:The results indicate that C-glycosyl flavone may exert induction of apoptosis, cell cycle arrest and inhibition of angiogenesis via CDK6. Thus, targeting CDK6 using C-glycosyl flavone may serve as a novel therapeutic approach for the treatment of breast, hepatic and colon cancers.

A new C-glycosyl flavone and a new neolignan glycoside from Passiflora edulis Sims peel

A new C-glycosyl flavone, Chrysin-8-C-(2″-O-β-6-deoxy-glucopyranosyl)-β-D-glucopyranoside (1), a new neolignan glycoside, citrusin G (2), as well as 15 known compounds (3–17) were isolated from the peel of Passiflora edulis Sims. The structure determinations were primarily based on comprehensive spectroscopic analyses, and the absolute configuration of 2 were unequivocally determined by the CD experiment and chemical transformation. Compound 1 represents the rare examples of the flavonoid featuring a deoxy glucose sugar moiety. Compounds 5, 7 and 9 exhibited moderate inhibitory effects on nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) in RAW 264.7 cells, with IC50 values of 34.92, 16.12 and 26.67 μM, respectively.

Orientin, a C-glycosyl dietary flavone, suppresses colonic cell proliferation and mitigates NF-κB mediated inflammatory response in 1,2-dimethylhydrazine induced colorectal carcinogenesis

Orientin, a C-glycosyl dietary flavone profusely found in rooibos tea and passion fruit have gained much attention owing to their multiple pharmacological potentials. The present study intends to investigate the anti-proliferative and anti-inflammatory efficacy of Orientin in 1,2-dimethyl hydrazine (DMH) induced colorectal cancer (CRC) in rats. Animals were arbitrarily segmented into six groups and fed with high-fat diet. Group 1 served as control. Group 2 received weekly subcutaneous injections of DMH (20 mg/kg b.w.), for first 15 weeks. Group 3 administered with Orientin (10 mg/kg b.w., i.p.) whereas Groups 4–6 treated with Orientin in three phases, namely initiation (along with DMH), post-initiation (post-DMH injection) and entire period. Orientin ameliorates tumor marker levels significantly (p < 0.05) and reinstates the histological changes induced by DMH. The proliferative markers (PCNA and Ki67) were observed to be suppressed significantly (p < 0.05) in Orientin treated rats. Orientin abrogates (p < 0.05) the inflammatory mast cells and diminishes the expression of pro-inflammatory NF-κB and cytokines (TNF-α and IL-6). It also down-regulates over expression of inflammatory inducible enzymes (iNOS and COX-2) significantly (p < 0.05) and further substantiated by GLIDE XP and QPLD studies. Overall results promptly elucidate the anti-proliferative and anti-inflammatory efficacy of Orientin against CRC. Orientin can be developed as a promising chemotherapeutic agent, on further validation of other molecular mechanisms.

C-glycosyl Flavone from Urginea indica Inhibits Growth and Dissemination of Ehrlich Ascites Carcinoma Cells in Mice.

C-glycosyl flavone, a phytochemical constituent in U.indica bulb, has been reported to possess cytotoxic activity. The present study aims to investigate the toxicity and anticancer potentials of C-glycosyl flavone against Ehrlich ascites carcinoma mice model. In present study, acute and chronic toxicity along with antitumor activity of C-glycosyl flavone isolated from U.indica bulb were Performed using in vitro and in vivo methods. Acute and chronic toxicity of C-glycosyl flavone was evaluated using Swiss albino mice. The effect of C-glycosyl flavone on proliferation of Ehrlich ascites carcinoma (EAC) cells was determined. Further, growth inhibition and dissemination were studied using EAC induced mice model. C-glycosyl flavone showed significant therapeutic potency against EAC cells in terms of reduced viability, cell cycle arrest, induction of apoptosis, inhibition of capillary formation, reduced VEGF levels. Moreover, there was reduction in body weight, tumor volume, viable tumor cells, increased survival of EAC induced mice upon C-glycosyl flavone treatment. Treatment also reduced dissemination of EAC cells into heart, kidney, liver and brain and diminished the pathological alterations induced by EAC cells in mice. In addition, there was an improvement in hemoglobin levels and counts of RBC, neutrophils, lymphocytes and monocytes in C-glycosyl flavone-treated mice with tumor. An enhancement of antioxidant status in C-glycosyl flavone treated EAC-bearing mice which appeared in terms of decreased serum thiobarbituric acid reactive substance and lipid peroxidation, increased GSH, SOD, Catalase and GPX. These results were comparable to a standard 5- fluorouracil treatment. C-glycosyl flavone exhibited safety profile in toxicity studies. Our study confirms the therapeutic potency of C-glycosyl flavone against EAC in inhibition of dissemination and growth of EAC in mice.

Spectrometric analysis, phenolics isolation and cytotoxic activity of Stipagrostis plumosa (Family Poaceae)

Grasses (family Poaceae) are economically important plants; they are used as crops and animal foods. Stipagrostis plumosa (L.) Munro ex T. Anderson is a member of this family and subjected to chemical and biological studies. The chromatographic techniques, LC–ESI–MS and GC/MS were used for identification of polar and non-polar compounds in its extract. Ten compounds, including one new flavone glycoside; tricin 7-O-galactoside, three known flavones, three C-glycosyl flavones and three phenolic acids, were isolated from S. plumosa for the first time except tricin. Their structures were elucidated on the basis of extensive spectroscopic interpretation. In addition to the isolated compounds, eleven compounds were tentatively identified using LC–ESI–MS, five of them were detected for the first time from this species. 29 non polar compounds were identified using GC–MS analysis, representing 83.13% of S. plumosa diethyl ether extract. In addition to the DPPH activity evaluation, the crude extract and the isolated compounds were investigated against five human carcinoma cell lines; A549, HCT-116, HepG2, MCF-7 and PC3 at a concentration of 100 μg/ml. From the isolated compounds tricin and luteolin 6,8-di-C-glucoside could be considered as natural-free radical scavenging agents.

LC-ESI-TOF-MS and GC-MS profiling of Artemisia herba-alba and evaluation of its bioactive properties

In this work, LC–ESI-TOF–MS and GC-EI-MS were used to assess the potential of Artemisia herba alba as a source of health-promoting constituents. Besides, the antioxidant, the antimicrobial and the cytotoxic potentials were evaluated. A total of 86 metabolites, including C-glycosylated and methylated flavones, quinic acid derivatives, coumarins, sesquiterpenes lactones, terpenoids, fatty acids, carbohydrates, organic acids and alkaloids were identified, sixty five of them were reported for the first time in A. herba alba. The main compounds were di-O-caffeoylquinic acids, artemisinic acid, menthol, α-ketoglutaric acid, scopolin, isoschaftoside and sucrose. Furthermore, results showed that A. herba alba possess high total antioxidant activity (Total antioxidant activity=423mg gallic acid equivalent/g dry weight), strong potential anticancer capacity against MCF-7 breast cancer and HeLa human cervical cell lines (IC50 of 15 and 70μg/ml, respectively), and moderate antibacterial activity against S. aureus, B. thurigiensis and A. hydrophila. These results support the use of this plant as alternative bioactive ingredient for functional foods, dietary supplements or nutraceuticals.

Genotoxicity and Antigenotoxicity Assessments of the Flavonoid Vitexin by the Drosophila melanogaster Somatic Mutation and Recombination Test.

Vitexin is a C-glycosylated flavone found in various medicinal plants with several proven biological properties such as anti-inflammatory, antispasmodic, antimicrobial, cytotoxic, and antioxidant activities. Considering that the human population consumes many foods that contain this flavonoid, the objective of this study was to investigate the genotoxic and the antigenotoxic potentials of vitexin by the SMART (Somatic Mutation and Recombination Test) in Drosophila melanogaster wings, in vivo. To evaluate the genotoxic activity, larvae obtained from standard (ST) and high bioactivation (HB) crosses were chronically treated with different concentrations of vitexin (0.15, 0.3, and 0.6 mM). For the evaluation of antigenotoxic activity, the same vitexin concentrations were associated with two damage inducing agents: doxorubicin (0.2 mM) and benzo[a]pyrene (1.0 mM). The results obtained for genotoxic activity showed that vitexin did not induce a statistically significant increment in the frequency of mutant spots, when compared to control. The results for the evaluation of antigenotoxicity indicated that the flavonoid statistically reduced the frequency of mutant spots, when compared to those treated with only the damage inducing agents. Thus, this article presents results that have demonstrated the antigenotoxic activity of vitexin, which could be applied in new studies for the development of drugs with chemoprotective effects.

Bioactivity-guided Study of Passiflora caerulea L. Leaf Extracts.

Passiflora species were known by their anticonvulsant, anxiolytic and sedative activities. The aim of this study was to investigate the chemical composition of the most active leaf extract of Passiflora caerulea L. grown in Egypt. The ethanolic extract of the leaves exhibited higher activity than aqueous extract as anticonvulsant (63% potency relative to carbamazepine), analgesic (70% potency relative to indomethacin), antioxidant (71% potency relative to vitamin E), anti-inflammatory (90% potency relative to indomethacin) and antipyretic (90% potency relative to paracetamol). Fractions obtained successively from the ethanolic extract were then subjected to the same biological testing demonstrating that the ethyl acetate fraction was the most active in all activities (50, 96, 80, 63 % potency relative to reference standards used in each of the selected activity, respectively) followed by n-butanol then n-hexane and chloroform fractions. Purification of the anticonvulsant sub-fractions obtained by column chromatography of ethyl acetate fraction, led to the isolation of three compounds that were identified by physical and spectroscopic techniques as Lucenin II (1), 4-hydroxycinnamic acid (2) and Chrysin 6-C-β-D-glucoside (3). The amount of Chrysin 6-C-β-D-glucoside was found to be 0.0184 g % w/w of the dried leaves using HPLC method that showed linearity (R2 = 0.9996) over the range 0.015-0.25 mg/mL. C-glycosyl flavones and hydroxycinnamic acid derivatives may thus be the responsible principles for the biological activity of the plant under investigation. Moreover, RAPD technique was performed for the genetic characterization and authentication of the plant, where 106 fragments were recorded after DNA amplification with fifteen primers.

The Chemical Constituents of Uninvestigated Plants in Hiroshima Prefecture.

Recently, the investigation of bioactive constituents from natural products has been performed extensively around the world, yet many plants remain to be studied, even now. The author is especially interested in saponins, which are included in various natural products and Kampo medicines. Based on these study aims, we isolated the chemical constituents of Dianthus japonicus and Clethra barbinervis. The aerial parts of Dianthus japonicus were isolated into nine new (1-9) and seven known oleanane-type triterpene saponins. The structural elucidation of their chemical constituents was examined by several spectroscopic methods. Two new C-glycosyl flavones, two glycosidic derivative of anthranilic acid amides and a maltol glucoside were also isolated from this plant. The isolated compounds were evaluated according to cytotoxic inhibition toward A549 cell lines. Compounds 7-9 showed moderate inhibitory activity. The isolation of a MeOH extract of Clethra barbinervis leaves led to three new triterpene glucosides, i.e. an ursane (ryobunin A, 22), a seco-ursane (ryobunin B, 23) and an oleanane-type glucoside (ryobunin C, 24), along with four known compounds.

Comprehensive characterization of C-glycosyl flavones in wheat (Triticum aestivum L.) germ using UPLC-PDA-ESI/HRMSn and mass defect filtering.

A comprehensive characterization of C-glycosyl flavones in wheat germ has been conducted using multi-stage high resolution mass spectrometry (HRMSn ) in combination with a mass defect filtering (MDF) technique. MDF performed the initial search of raw data with defined C-glycosyl flavone mass windows and mass defect windows to generate the noise-reduced data focusing on targeted flavonoids. The high specificity of the exact mass measurement permits the unambiguous discrimination of acyl groups (nominal masses of 146, 162 and 176.) from sugar moieties (rhamnose, glucose or galactose and glucuronic acid). A total of 72 flavone C-glycosyl derivatives, including 2 mono-C-glycosides, 34 di-C-glycosides, 15 tri-glycosides, 14 acyl di-C-glycosides and 7 acyl tri-glycosides, were characterized in wheat germ, some of which were considered to be important marker compounds for differentiation of whole grain and refined wheat products. The 7 acylated mono-O-glycosyl-di-C-glycosyl flavones and some acylated di-C-glycosyl flavones are reported in wheat for the first time. The frequent occurrence of numerous isomers is a remarkable feature of wheat germ flavones. Both UV and mass spectra are needed to maximize the structure information obtained for data interpretation. Copyright © 2016 John Wiley & Sons, Ltd.

Oenocarpus bacaba and Oenocarpus bataua Leaflets and Roots: A New Source of Antioxidant Compounds.

Native palm trees fruit from the Amazonian rainforest, Oenocarpus bacaba and Oenocarpus bataua, are very often used in the diet of local communities, but the biological activities of their roots and leaflets remain poorly known. Total phenolic content (TPC) and antioxidant activity of root and leaflet extracts from Oenocarpus bacaba and Oenocarpus bataua were assessed by using different chemical assays, the oxygèn radical absorbance capacity (ORAC), the 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical-scavenging capacity and the ferric-reducing ability of plasma (FRAP). Cellular antioxidant activity and cytotoxicity were also measured in Normal Human Dermal Fibroblasts. The polyphenolic composition of Oenocarpus extracts was investigated by LC-MSn. Oenocarpus leaflet extracts were more antioxidant than root extracts, being at least as potent as Euterpe oleracea berries known as superfruit. Oenocarpus root extracts were characterized by hydroxycinnamic acids (caffeoylquinic and caffeoylshikimic acids), while leaflet extracts contained mainly caffeoylquinic acids and C-glycosyl flavones. These results suggest that leaflets of both Oenocarpus species could be valorized as a new non-cytotoxic source of antioxidants from Amazonia, containing hydroxycinnamic acids and flavonoids, in the pharmaceutical, cosmetic or agri-food industry.

Identification and Characterization of Maize salmon silks Genes Involved in Insecticidal Maysin Biosynthesis.

The century-old maize (Zea mays) salmon silks mutation has been linked to the absence of maysin. Maysin is a C-glycosyl flavone that, when present in silks, confers natural resistance to the maize earworm (Helicoverpa zea), which is one of the most damaging pests of maize in America. Previous genetic analyses predicted Pericarp Color1 (P1; R2R3-MYB transcription factor) to be epistatic to the sm mutation. Subsequent studies identified two loci as being capable of conferring salmon silks phenotypes, salmon silks1 (sm1) and sm2 Benefitting from available sm1 and sm2 mapping information and from knowledge of the genes regulated by P1, we describe here the molecular identification of the Sm1 and Sm2 gene products. Sm2 encodes a rhamnosyl transferase (UGT91L1) that uses isoorientin and UDP-rhamnose as substrates and converts them to rhamnosylisoorientin. Sm1 encodes a multidomain UDP-rhamnose synthase (RHS1) that converts UDP-glucose into UDP-l-rhamnose. Here, we demonstrate that RHS1 shows unexpected substrate plasticity in converting the glucose moiety in rhamnosylisoorientin to 4-keto-6-deoxy glucose, resulting in maysin. Both Sm1 and Sm2 are direct targets of P1, as demonstrated by chromatin immunoprecipitation experiments. The molecular characterization of Sm1 and Sm2 described here completes the maysin biosynthetic pathway, providing powerful tools for engineering tolerance to maize earworm in maize and other plants.