RESUMO
The major falvonoid constituents of the Antarctic grass, Deschampsia antarctica, are shown to be the C-glycosylfavones, isoswertiajaponin (7-O-methylorientin) 2''-O-beta-arabinopyranoside and orientin. These are accompanied by lower levels of orientin 2''-O-arabinopyranoside, isoswertisin (7-O-methylvitexin) 2''-O-beta-arabinopyranoside, acylated derivatives, isoswertisin, isoswertiajaponin and tricin. A preliminary study suggests that the overall level of flavonoids in Deschampsia increases during the Antarctic mid-summer.
Assuntos
Flavonoides/química , Glicosídeos/química , Poaceae/química , Regiões Antárticas , Flavonoides/isolamento & purificação , Flavonoides/metabolismo , Glicosídeos/isolamento & purificação , Glicosídeos/metabolismo , Espectroscopia de Ressonância Magnética , Folhas de Planta/química , Folhas de Planta/metabolismo , Poaceae/metabolismo , Estações do Ano , Espectrofotometria UltravioletaRESUMO
In the course of a chemotaxonomic study of the genus Actinidia a new flavonol triglycoside, quercetin 3-O-beta-D-[2G-O-beta-D-xylopyranosyl-6G-O-alpha-L-rhamnopyranosyl] glucopyranoside was identified amongst the 15 flavonols found in Actinidia arguta var. giraldii. This compound was characterized, along with quercetin 3-O-beta-D-xylopyranosyl-(1-2)-O-beta-D-glucopyranoside, by 1H and 13C NMR spectroscopy. The kaempferol analogues were also isolated.
