five flavonoid glycosides were isolated from the n-butanol soluble fraction of the ethanolic extract of rapistrum rugosum and their structures were assigned from 1h- and 13c-nmr spectra (dept) with 2d nmr as quercetin-3-o-α-l-rhamnopyranoside (1), quercetin-3-o-β-d-xyloside (2), quercetin, 3-o-α-l-arabinopyranoside,7-o-α-l-rhamnopyranoside (3), kaempferol 3-o-α-l-arabinopyranoside, 7-o-α-l-rham...

Quercetin and gallic acid are natural activators of the transcription factor Nrf2, which regulates the expression of many cytoprotective enzymes including heme oxygenase-1 (HO-1). We developed procedures for the synthesis of monogalloyl esters of quercetin and taxifolin (dihydroquercetin), namely, 3-O-galloylquercetin and 7-O-galloyltaxifolin, and examined their effect on the Nrf2 pathway in RA...

− A new quercetin 3-O-trisaccharide was isolated from the leaves of Rubus crataegifolius (Rosaceae). The structure of this compound was determined as quercetin 3-O-α-L-arabinofuranosyl-(1→ 2)-β-D-xylopyranosyl(1→ 2)-β-D-galactopyranoside on the basis of 2D-NMR spectroscopic data. This flavonol glycoside was isolated for the first time from a natural source.

AIM: To identify the chemical constituents in Cuscuta Chinensis. METHODS: A High-performance liquid chromatography (HPLC) method combined with quadrupole-time-of-flight-mass spectrometry (QTOF-MS) has been developed for precise separation and structural identification of components in Cuscuta Chinensis. Mass spectrometry was performed in reflective time-of-flight using electron spraying ionizat...

Bioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrh...

A rapid and simple method has been developed for the screening and identification of natural antioxidants from the leaves of Acer ginnala Maxim.( AG). The process is that upon reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH), the white yellow spots of compounds with potential antioxidant effects will be significantly observed on the thin-layer chromatography (TLC), and possible structures wil...

A rapid and simple method has been developed for the screening and identification of natural antioxidants from the leaves of Acer ginnala Maxim.( AG). The process is that upon reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH), the white yellow spots of compounds with potential antioxidant effects will be significantly observed on the thin-layer chromatography (TLC), and possible structures wil...

FOUR KNOWN FLAVONOIDS quercetin 3-O-β-D-rutinoside (Q3Rut), myricetin 3-O-β-D-galactopyranoside (M3Gal), quercetin 3-O-β-D-galactopyranoside (Q3Gal) and quercetin 3-O-β-D-glucopyranoside (Q3Glc), for the first time were isolated from aerial parts of Euphorbia microsciadia. The chemical structure of them was elucidated on the basis of 1 and 2 D-NMR spectra and different spectroscopic techniques....

The present study aimed to investigate the chemical composition, and the antioxidant and antiproliferative activities of Ailanthus excelsa, a plant used in Egyptian traditional medicine. Chromatographic separation of a methanol extract of A. excelsa leaves yielded four flavones, namely apigenin (1), apigenin 7-O-beta-glucoside (2), luteolin (3), and luteolin 7-O-beta-glucoside (4), and seven fl...

Phytochemical investigation of the methanolic extract of Tagetes minuta L. (Asteraceae) leaves resulted in the isolation and identification of two new compounds: 5-methyl-2,2',5',2'',5'',2''',5''',2''''-quinquethiophene (1) and quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside) (9), in addition to seven known compounds: quercetin-3,6-dimethyl ether (2), quercetin-3-methyl ether (3), quercetin...