Isovitexin

About: Isovitexin is a research topic. Over the lifetime, 526 publications have been published within this topic receiving 11525 citations. The topic is also known as: 6-Glucosylapigenin & Isovitexin.

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.

Bioassay-guided isolation of allelochemicals from Avena sativa L.: allelopathic potential of flavone C-glycosides

Abstract: The allelopathic potential of oat (Avena sativa L., var. Argentina, Poaceae, Cyperales) was investigated under field and laboratory conditions. In field trials, oat plants provided an effective control of weeds, showing a species-specific impact: the most abundant weed species, Picris echioides was reduced by 94% in number of individuals. Aerial parts of oat plants, harvested immediately before soil incorporation, were utilized in a bioassay-guided isolation, which was aimed at identifying the phytotoxic compounds in a methanol/water extract of the aerial parts of the plants. Further partitions of extract gave an active n-butanol portion composed of flavonoids and saponins. Phytotoxic activity was detected for the flavonoid fraction, whereas no activity was found for the saponin mixture. Germination of an indicator species, lettuce (Lactuca sativa L.), was completely inhibited at flavonoid concentrations of 6.7, 10.0, and 20.0 mg/mL, and conversely the number of abnormal seedlings was greatly increased from 2% of control to over 96% at concentrations equal to 6.7 and 10.0 mg/mL. Analysis of the flavonoid fraction by ESI-MS techniques identified two components of the mixture as isoorientin 2-O-glucoside and isovitexin 2″-O-arabinoside. Saponins were characterized as avenacoside A, avenacoside B, 26-desglucoavenacoside A, and 26-desglucoavenacoside B. Both flavone C-glycosides and saponins were isolated previously from oat.