RESUMO
Three acylated flavonol glycosides have been identified from leaves of Planchonia grandis Ridley. They possess kaempferol as aglycone and two triglycosidic chains substituting hydroxyl groups at the 3- and 7-positions. The first glycosidic unit of each chain is esterified by a cis or trans p-coumaric acid. Structural elucidation was achieved by means of UV, NMR and mass spectrometry.
Assuntos
Flavonóis/química , Flavonóis/isolamento & purificação , Glicosídeos/química , Glicosídeos/isolamento & purificação , Lecythidaceae/química , Acilação , Sequência de Carboidratos , Ácidos Cumáricos/química , Esterificação , Quempferóis/química , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Propionatos , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Nine new acylated triterpenoid saponins (4-12) were isolated from the stem bark of Foetidia africana. They all possess barringtogenol C as the aglycone, esterified by acetic and/or isovaleric acids. The sugar chain consists of up to three units: D-glucuronic acid (GlcUA) linked to C-3 of the aglycone and substituted by D-galactose (Gal) (at GlcUA C-2) and/or L-rhamnose (Rha) (at GlcUA C-4). The structures were established by acid and alkaline hydrolysis, by NMR experiments including (1)H-(1)H (COSY, HOHAHA, ROESY) and (1)H-(13)C (HSQC, HMBC) spectroscopy, and by mass spectrometry (ESIMS, ESIMS(n)).