Flavonoid C- and O-glycosides from the Mongolian medicinal plant Dianthus versicolor Fisch

Eighteen flavonoids were identified from an aqueous extract of the aerial parts of Dianthus versicolor, a plant used in traditional Mongolian medicine against liver diseases. The flavonoid C- and O-glycosides isoorientin-7-O-rutinoside, isoorientin-7-O-rhamnosyl-galactoside, isovitexin-7-O-rutinoside, isovitexin-7-O-rhamnosyl-galactoside, isoscoparin-7-O-rutinoside, isoscoparin-7-O-rhamnosyl-galactoside, isoscoparin-7-O-galactoside, and isoorientin-7-O-galactoside were isolated and structurally elucidated. Their structures were established on the basis of extensive spectroscopic techniques including LC–UV–DAD, LC–MSⁿ, LC–HRMS, 1D and 2D NMR spectroscopy, and by GC–MS analysis after hydrolysis. Flavonoids with such a high glycosylation pattern are rare within the genus Dianthus. Furthermore, isovitexin-7-O-glucoside (saponarin), isovitexin-2″-O-rhamnoside, apigenin-6-glucoside (isovitexin), luteolin-7-O-glucoside, apigenin-7-O-glucoside, as well as the aglycons luteolin, apigenin, chrysoeriol, diosmetin, and acacetin were identified by TLC and LC–DAD–MSⁿ in comparison to reference substances or literature data. The NMR data of seven structures have not been reported in the literature to date.