Showing papers on "Isovitexin published in 2001"

Characterization of the polyphenolic composition of purple loosestrife (Lythrum salicaria)

Abstract: Phenolic compounds of purple loosestrife (Lythrum salicaria L.) were analysed by the use of liquid chromatography-mass spectrometry (LC/MS) equipped with atmospheric pressure chemical ionisation (APCI) and electrospray ionisation (ESI). The presence of vitexin and orientin as well as their isomers, isovitexin and isoorientin, were confirmed using ion trap multiple stage LC/MS3 analysis. Several phenolic acids and tannins were also detected. Ellagitannins, vescalagin and pedunculagin, are reported from the plant for the first time.

Identification and simultaneous analysis of harmane, harmine, harmol, isovitexin, and vitexin in passiflora incarnata extracts with a novel hplc method

Abstract: A high performance liquid chromatographic method for the simultaneous analysis of two flavonoids (iso-vitexin and vitexin), and three indole alkaloids (harmane, harmine, and harmol) was developed. This method was then utilised to quantitate levels of these five constituents in methanolic extracts of Australian Passiflora incarnata. HPLC analysis was performed using a Waters™ Novapak C18 (150 × 4 mm, 4 μm) column, with a gradient solvent system of methanol-water-acetic acid. Detection was achieved by PDA UV (254 nm) and fluorescence (excitation 254 nm, emission 414 nm), utilising the external standard method to obtain quantification.

Isovitexin o-glucosides from Aquilegia vulgaris L.

Abstract: 4'-O-beta-glucopyranoside of isovitexin from the leaves with stems and 4'-O-delta-glucopyranoside of -2"-O-beta-glucopyranosylisovitexin from the flowers of Aquilegia vulgnris L. were isolated. The structures of the compounds were determined by chemical and spectroscopic methods.

Phenolic constituents of Phenax angustifolius.

Abstract: Fractionation of an ethanolic extract of the leaves of Phenax angustifolius has resulted in the isolation of two new lignans, 2-hydroxy-2-(3‘,4‘-dihydroxyphenyl)methyl-3-(3‘ ‘,4‘ ‘-dimethoxyphenyl)methyl-γ-butyrolactone (1) and 2-hydroxy-2-(4‘-O-β-d-glucopyranosyl-3‘-hydroxyphenyl)methyl-3-(3‘ ‘,4‘ ‘-dimethoxyphenyl)methyl-γ-butyrolactone (2), and three known compounds, vitexin, isovitexin, and quercetin 3-O-α-l-rhamnopyranoside. The structures of 1 and 2 were determined using spectroscopic methods.

Chemical Constituents Of The Roots Of Vitex Negundio

Abstract: Five compounds were isolated from the methanolic extract of the roots of Vitex negundo linn and purified by crystalisation and preparative TLC. They were identified as 2 I², 3I±-diacetoxyoleana-5,12-dien-28-oic acid, 2I±, 3I²-dihydroxyoleana-5,12-dien-28-oic acid, 2I±, 3I²-diacetoxy-18-hydroxyoleanaQ,12-dien-28-oic acid, vitexin and isovitexin by spectral data and chemical conversions.

C-glycosylflavones in the genus Azolla

Abstract: Two C-glycosylflavones were isolated from the root extracts of fresh material of Azolla fihculoides Lain. and A. pinnata subsp, africana (Desv.) R. M. K. 8aunders & K. Fowler. They were also detected in herbarium material of A. caroliniana Willd. and A. nilotica Decne. ex Mett. Their structures were assigned to homoorientin (luteolin 6-C-glucosside) and saponarin (isovitexin 7- O-glucoside). Homoorientin and saponarin have not been previously reported in the genus Azolla. Our results indicate that roots and fronds present a different polyphenolic composition. Previous studies and our own results point to a certain chemical homogeneity in the genus Azolla, with regard to polyphenols.