3-Hydroxy-3-methylglutaryl flavonol glycosides from Oxytropis falcata.

Five new 3-hydroxy-3-methylglutaryl (HMG) flavonol 3-O-glycosides, named oxytroflavosides A-E (1-5), and two new rhamnocitrin 3-O-glycosides, oxytroflavosides F and G (6 and 7) were isolated from the n-BuOH-soluble fraction of an EtOH extract of Oxytropis falcata together with seven known kaempferol glycosides (8-14), of which six were isolated from the genus Oxytropis for the first time. The structures of these compounds were elucidated by spectroscopic techniques and chemical methods. The absolute configuration of HMG in compounds 1-5 was determined to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. Compounds 1-10 were evaluated for anti-inflammatory activities using lipopolysaccharide-induced RAW 264.7 cells, but none of them showed inhibitory effects on NO production.