ABSTRACT
The leaves of Campylospermum elongatum have furnished the cyano-glycoside (lithospermoside), nine isomeric biflavonoid derivatives among which five are I3-II6 linked (robustaflavone; 4'-O-methyl robustaflavone; 4',4â³'-di-O-methyl robustaflavone; 7,4',4â³-tri-O-methyl robustaflavone; 4',7â³-di-O-methyl robustaflavone) and four I3-II8 linked (amentoflavone; 7-O-methyl amentoflavone; 7,7â³-di-O-methyl amentoflavone; 7, 4',7â³-tri-O-methyl amentoflavone) and a flavone glycoside, 4â³-O-methyl-7-O-ß-d-galactosylapigenin. All structures were established from a complete spectroscopic analysis (MS, IR, 1D, and 2D NMR, including HSQC, HMBC, and NOESY) as well as by comparing the obtained spectroscopic data with literature. This is the first report on the characterization of 4'-O-methyl-7-O-ß-d-galactosylapigenin from the genus campylospermum and thus has important chemotaxonomic implications.
Subject(s)
Flavonoids/isolation & purification , Ochnaceae/chemistry , Ethanol , Flavones/chemistry , Flavones/isolation & purification , Flavonoids/chemistry , Hydrolysis , Methanol , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Leaves/chemistry , Solvents , Spectrometry, Fluorescence , Spectrophotometry, Infrared , Spectroscopy, Fourier Transform InfraredABSTRACT
Six new compounds, comprising three flavonoid glycosides and their respective coumaroyl esters, have been isolated and characterized from the methanol extract of the leaves of Campylospermum calanthum, along with three known flavonoid aglycones, 7-O-methyl apigenin (1), 7-O-methyl luteolin (2), and 7-O-methyl quercetin (3). Their structures were elucidated based on chemical evidence as well as spectroscopic analysis including 1D and 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY) spectroscopy and by comparing their spectral data with those reported for related compounds.
