Flavonol Glycosides with Antioxidant Activity from the Aerial Parts of Epimedium koreanum Nakai

The aerial parts of Epimedium koreanum Nakai have been used to stimulate hormone secretion in treating impotence. Ten flavonol glycosides, 3,4,5-trihydroxy-8-prenylflavone 7-O-[${\beta}$-D-glucopyranosyl($1{\rightarrow}2$)-${\beta}$-D-glucopyranoside] (1), hyperoside (2), icarisid II (3), 2"-O-Rhamnosylicarisid II (4), epimedin A (5), epimedin B (6), epimedin C (7), icariin (8), hexandraside E (9), and epimedoside A (10) were isolated from the an ethylacetate soluble extracts of the aerial parts of Epimedium koreanum Nakai through activity-monitord fractionation and isolation method. The structures of compounds 1 - 10 were elucidated by high resolution fast atom bombardment mass spectrometry and two dimentional nuclear magnetic resonance spectroscopy analysis. Compounds 1 and 4 showed potent antioxidant activity, with $IC_{50}$ values of 19.7 and 11.5 ${\mu}g$/mL and 88.2 and 90.5 ${\mu}M$, respectively.