Showing papers on "Isovitexin published in 2008"

Antioxidant constituents in the dayflower (Commelina communis L.) and their α-glucosidase-inhibitory activity

Abstract: The dayflower, Commelina communis L., contains 1-deoxynojirimycin (DNJ) and (2R,3R,4R,5R)2,5-bis(hydroxymethyl)-3,4-dihydroxypyrrolidine (DMDP), potent α-glucosidase inhibitors. The extracts and powder of this herb are important food materials for prophylaxis against type 2 diabetes. Eleven flavonoid glycosides as antioxidants, isoquercitrin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-β-d-glucoside, glucoluteolin, chrysoriol-7-O-β-d-glucoside, orientin, vitexin, isoorientin, isovitexin, swertisin, and flavocommelin, were identified from the aerial parts of C. communis. Their antioxidant activities were measured using in vitro assays employing the 1,1-diphenyl-2-picrylhydrazyl radical- and superoxide radical-scavenging assays. The results showed that glucoluteolin, orientin, isoorientin, and isoquercitrin are the predominant antioxidants in this herb. Moreover, isoquercitrin, isorhamnetine-3-O-rutinoside, vitexin, and swertisin inhibited the activity of α-glucosidase from rat intestine.

Analysis of Selected Phenolic Acids and Flavonoids in Amaranthus cruentus and Chenopodium quinoa Seeds and Sprouts by HPLC

Abstract: Summary. Red amaranth (Amaranthus cruentus) and quinoa (Chenopodium quinoa) are pseudocereals with particularly highly regarded nutritional value. Because of the high biological significance of the flavonoids and phenolic acids in these plants, qualitative and quantitative analysis has been performed by HPLC. Extracts from the seeds of two amaranth varieties (A. cruentus v. Rawa and v. Aztek) and quinoa seeds, and their sprouts grown in natural conditions and in the dark were analyzed. The main phenolic acid found both in seeds and sprouts was gallic acid. p-Hydroxybenzoic acid, vanillic acid, p-coumaric acid, caffeic acid, and cinnamic acid were also found in the seeds and pcoumaric acid, syringic acid, and ferulic acid in the sprouts. The main flavonoid found in the sprouts was rutin. Vitexin, isovitexin, and morin were also detected in the sprouts, and orientin, vitexin, isovitexin, morin, and traces of hesperidin and neohesperidin in the seeds. Although sprouting conditions (daylight or darkness) had no effect on gallic acid content, light caused an increase in the amount of rutin and darkness resulted in increased amounts of isovitexin and vitexin.

HPLC-PDA-MS and NMR Characterization of C-Glycosyl Flavones in a Hydroalcoholic Extract of Citrus aurantifolia Leaves with Antiplatelet Activity

Abstract: A hydroalcoholic extract of lime ( Citrus aurantifolia) leaves has been developed in Cuba to be used as a nutritional supplement and phytomedicine in the form of tincture (TLL). A HPLC-PDA-ESI/MS/MS method has been used for the comprehensive analysis of C-glycosyl flavones in TLL. Six C-glycosyl flavones were characterized and, to confirm the proposed structures and to elucidate the nature of the sugar units, a preparative procedure was applied, and isolated compounds were characterized by NMR. Apigenin-6,8-di-C-beta-D-glucopyranoside (vicenin II) (1), diosmetin-6,8-di- C-beta- d-glucopyranoside (2), apigenin-8-C-beta-D-glucopyranoside (vitexin) (3), apigenin-8-C-[alpha-L-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (4), apigenin-6-C-[alpha-l-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (5). and apigenin-6-C-beta-D-glucopyranoside (isovitexin) (6) were identified in TLL and quantified by HPLC-PDA. Compounds 4 and 5 were two new arabinosyl derivatives of vitexin and isovitexin. Inhibitor effect of TLL on platelet aggregation induced by physiological agonists of platelets was evaluated in human plasma. TLL inhibited significantly ADP and epinephrine-induced platelet aggregation in a concentration-dependent manner (IC 50=0.40 and 0.32 mg/mL, respectively).

Flavonoids in the leaves of Oxalis corniculata and sequestration of the flavonoids in the wing scales of the pale grass blue butterfly, Pseudozizeeria maha

Abstract: Three C-glycosylflavones in the leaves of Oxalis corniculata, the host plant of the lycaenid butterfly pale grass blue (Pseudozizeeria maha), were identified as 6-C-glucosylluteolin (isoorientin), 6-C-glucosylapigenin (isovitexin) and isovitexin 7-methyl ether (swertisin). Comparative spectral and HPLC analyses between the leaf extract of the host plants and the wings of P. maha showed selective uptake of the host-plant flavonoid isovitexin to the wings of the butterfly.

Phenolic composition of rhubarb

Abstract: Extracts of different parts (leaves, petioles and rhizomes) of domestic garden rhubarb (hybrids of Rheum rhabarbarum L. and Rheum rhaponticum L.) were investigated for their content of phenolic ingredients. Two stilbenes (trans-rhapontigenin, trans-desoxyrhapontigenin), five stilbene glycosides (trans-rhaponticin, cis- and trans-desoxyrhaponticin, trans-resveratrol-4′-O-β-d-glucopyranoside, trans-piceatannol-3′-O-β-d-glucopyranoside) and seven flavonoids [rutin, quercetin-3-O-glucuronide, isovitexin, 6,8-di-C-β-d-glucosylapigenin, 6-C-β-d-glucosyl-8-C-β-d-arabinosylapigenin (schaftoside), 6-C-β-d-arabinosyl-8-C-β-d-glycosylapigenin (isoschaftoside), (+)-catechin] were unequivocally established. Separation was done in two steps. Multilayer countercurrent chromatography was applied to separate different extracts of plant material. Preparative HPLC was then used to obtain pure substances. The purity and identity of isolated compounds was confirmed by different NMR experiments, HR-MS and HPLC-DAD analysis.

Determination of vitexin and isovitexin in pigeonpea using ultrasonic extraction followed by LC-MS.

Abstract: A method based on ultrasonic extraction (USE) followed by LC-MS is presented for the determination of vitexin and isovitexin in pigeonpea extracts in this study. The influential parameters of the USE procedure were optimized, and the optimal conditions were as follows: extraction solvent, 60% ethanol solution; liquid/solid ratio 10:1 (mL/g), extraction power, 250 W; temperature, 40-50 degrees C; and three extraction cycles, each cycle 15 min. Validation of the USE method was performed in terms of repeatability and reproducibility. RSDs for extraction yields were lower than 5.85 and 8.09%, respectively. The LOD and LOQ of chromatographic determination were 0.96 and 3.2 ng/mL for vitexin and 0.84 and 2.8 ng/mL for isovitexin. The method was also successfully applied for the determination of vitexin and isovitexin in stems, leaves, and root extracts of pigeonpea. From all these results, we may conclude that the developed method is appropriate for the quality control of pigeonpea and other plant extract products developed from pigeonpea.

Antiradical activities of the extract of Passiflora incarnata.

Abstract: The objective of this work was to investigate the aqueous and ethanolic extracts of passionflower and the influence of the flavonoids they contain on the antiradical activity by DPPH* and ABTS* + methods. The data show that the Passiflora extract has not only sedative but also antiradical activity. The ethanol extract catches free radicals more effectively than the water extract. The strongest antiradical effect among the investigated flavonoids (chlorogenic acid, hyperosid, isovitexin, caffeic acid, quercetin, luteolin, orentin, rutin, scutelarein, vicenin and vitexin) was predetermined by vicenin, isovitexin and orentin. The antiradical activity increases with the increase of the concentration of the mentioned materials.

Composition and variability of phenolic compounds in Origanum vulgare from Lithuania

Abstract: was analysed by the HPLC method. Fourteen phenolic compounds, namely rosemarinic acid, chlorogenic acid, caffeic acid, hyperozide, naringin + rutin, luteolin, astragalin, vitexin, isovitexin, eriodictol, quercetin, naringenin were identified in the plant material. Rosemarinic acid was the dominant compound; its content in flower extracts ranged within 0.99–9.65mg/g, in leaves 1.11–7.42 mg/g and in stems 0.53–0.77 mg/g dry weight. Analysis of variance illustrated differences in the content of compounds among flowers, leaves and stems. The most distinct differences were observed in respect of the content of hyperozide, rosemarinic acid, chlorogenic acid, luteolin and quercetin. In order to study the infraspecific variability, the results of chemical analysis were submitted to a hierarchical cluster analysis. The flower extracts were allotted to five groups on the basis of phenolics quantitatives, whereas leaf extracts showed differences among four clusters. The chemical variability of the analysed accessions seems likely to result from the genetic variability, since the influence of environmental factors has been eliminated.Key words:

Aldose-reductase- and protein-glycation-inhibitory principles from the whole plant of Duchesnea chrysantha.

Abstract: Ellagic acid (1), 3,3'-di-O-methylellagic acid (2), 3,3',4-tri-O-methylellagic acid (3), isovitexin (4), kaempferol 3-O-beta-D-glucuronide methyl ester (5), quercetin 3-O-alpha-L-arabinopyranosyl-(1-->6)-beta-D-galactopyranoside (6), ursolic acid, pomolic acid, tormentic acid, euscaphic acid, euscaphic acid 28-O-beta-D-glucopyranoside, and maslinic acid were isolated from the AcOEt- and BuOH-soluble MeOH extract of Duchesnea chrysantha (whole plant) The isolates were subjected to in vitro bioassays to evaluate their inhibitory activity on rat-lens aldose reductase (RLAR) and formation of advanced glycation end products (AGEs) The ellagic acids and flavonoids, compounds 1-6, exhibited moderate inhibitory effects on RLAR However, compounds 1 and 4-6 showed excellent inhibitory activities towards the formation of AGEs This is the first report that 4 and 6 exhibit inhibitory activity towards AR and AGEs formation

Variation of Flavonoids Contents in Plant Parts of Mungbean

Abstract: This study carried out to investigate the variation of flavonoids contents in mungbean (Vigna radiata L.) according to plant parts, harvesting time, growth stage, and sowing time. Vitexin and isovitexin were found only in the seeds but not in the leaves, petioles, stems, and roots. Vitexin and isovitexin in seeds were detected only in the seed coat at concentration of 51.1 and , respectively, but not in the cotyledon. There were no differences in the content of vitexin and isovitexin in mungbean seeds according to early, recommended and late harvesting times. Rutin in leaves was isolated and identified as a functional substance. The content of rutin was the highest in the leaves and higher in the order of petioles and stems. However, there was no rutin in the seeds, roots, and pods. The highest rutin content in the leaves, petioles and stems was observed at the 3rd leaf stage, which was higher in the order of the 5th and 7th leaf stage.

Triterpenoids and Flavonoids from the Leaves of Microcos paniculata

Abstract: Ten compounds were isolated from the leaves of Microcos paniculata L. On the basis of spectral data, they were identified as friedelin (1), arjunglucosideⅡ (2), kaempferol-3-O-β-D-\[3,6-di-(p-hydroxycinnamoyl)\]-glucopyranoside (3), kaempferol-3-O-β-D-glucopyranoside (4), isorhamnetin-3-O-β-D-glucopyranoside (5), narcissin (6), vitexin (7), violanthin (8), isoviolanthin (9) and isovitexin (10). All these compounds were obtained from this plant for the first time.

[Simultaneous determination of four glycosylflavones from Lophatherum gracile by RP-HPLC].

Abstract: Objective To develop a RP-HPLC method for simultaneous determination of orientin, isorientin, vitexin and isovitexin in Lophatherum gracile from different habitat and harvesting time. Method The HPLC method was applied and the chromatographic column was a Waters XBridge C18 column (4.6 mm x 250 mm, 5 microm). The mobile phase consisted of methanol-0.05% acetic acid (35:65). The flow rate was 1.0 mL min(-1) and the detection wavelength was set at 340 nm. The column temperature was set at 25 degrees C. Result Four components were isolated well, the linear relationships were excellent. The mean recoveries and RSD values of orientin, isorientin, vitexin and isovitexin were 103.2%, 2.1%; 101.6%, 2.7%; 98.4%, 2.3%; 99.2%, 1.8%, respectively. Conclusion The HPLC method is simple, sensitive and reliable, and can be used for the quality control of the medicinal material.

Studies on glycosides from Gentiana veitchiorum

Abstract: Objective To study the chemical constituents of Gentiana veitchiorum. Method The chemical constituents were isolated by chromatography and identified by spectral data. Result Five glycosides, loganic acid (1), gentiopicroside (2), isoorientin 3'-methyl ether (3), isovitexin (4), isoorientin (5) were isolated and identified. Conclusion Compounds 1-5 were isolated from this plant for the first time.

Chemical constituents from herbs of Swertia delavayi

Abstract: Objective To isolate and identify the chemical constituents of 95% alcohol extract from Swertia delavayi. Method The compounds were isolated and purified by column chromatogrphy and their structures were identified by the physicochemical properties and spectral analyses. Result Seven compounds were isolated and identified as oleanolic acid (1), gentiopcroside (2), swertiamarin (3), daucosterol (4), swertiadecoraxanthone-II (5), isovitexin (6), isoorientin (7). Conclusion Compounds 2-7 were isolated from S. delavayi for the first time. While the compound 6 was firstly reported from the genus Swertia.

Determination of Contents of Vitexin and Isovitexin in Pigeonpea by HPLC

Abstract: A high-performance liquid chromatography(HPLC) method was established for determining contents of vitexin and isovitexin in the leaves,stems and roots of pigeonpea (Cajanus cajan(L.)Millsp). The analytes were separated on a HIQ Sil C18V(250 mm×4.6 mm,5 μm) column,using methanol-water-formic acid(35 ∶64.74 ∶0.26,volume ratio),as mobile phase,detection wavelength 330 nm,flow rate 1 mL/min,injection volume 10 μL,and column temperature 30 ℃. The calibration curves of vitexin and isovitexin showed good linearity within the ranges of 2-200 mg/L. For vitexin,relative standard deviation(RSD) of precision was not higher than 2.93 %,RSD of repeatability was 2.91 %,and recovery was 97.38 %; for isovitexin,RSD of precision was not higher than 2.69 %,RSD of repeatability was 3.37 %,and recovery was 98.63 %. Mass factions of vitexin and isovitexin in pigeonpea leaves,stems and roots were 0.768,0.066,0.183 mg/g and 0.799,0.139,0.013 mg/g,respectively. Pigeonpea leaves contain much higher amounts of vitexin and isovitexin than stems and roots,which could be developed as a good resource for obtaining vitexin and isovitexin on large scale.