A new flavonol glycoside from the aerial parts of Epimedium koreanum Nakai.

A new prenylated flavonol glycoside (1) was isolated from a 95% methanol extract of the dried and powdered aerial parts of Epimedium koreanum Nakai (Herba Epimedii), along with seven previously known flavonoids (2-8). The chemical structure of the new compound (1) was established to be 5-hydroxy-4'-methoxy-8-(2-hydroxy-3-methyl-3-butenyl)flavone 3-O-α-l-rhamnopyranosyl-7-O-β-D-gluco pyranoside on the basis of spectroscopic methods. The antioxidant activities of these compounds were determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and kaempferitrin (8) showed a high reactivity with DPPH.