Antioxidant flavonol glycosides from Herba epimedii

Herba Epimedii (Yinyanghuo in Chinese) is a traditional Chinese herbal medicine, which has been used as tonic, aphrodisiac and anti-rheumatic in China for thousands of years. It was proven to be an effective remedy for cardiovascular diseases, osteoporosis and for improving sexual and neurological functions. And it was verified that the effectiveness of Herba Epimedii is highly related to its antioxidant ingredients. Hence the antioxidant constituents from Herba Epimedii were investigated, and the ethyl acetate fraction of the methanolic extract of Herba Epimedii, which contains a major bioactive component icariin, showed highest DPPH radical scavenging activity. Several known and novel flavonol glycosides were isolated by silica gel open column chromatography and HPLC. Structures of the isolated compounds were identified by analyses of spectroscopic data from 1D- and 2D-NMR as well as UV, IR and MS. Details of isolation and structure elucidation will be discussed.