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-MS(n), 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-MS(n) in comparison to reference substances or literature data. The NMR data of seven structures have not been reported in the literature to date.