Antioxidant flavonoids from Epimedium wushanense

Abstract Two new flavonoids, wushanicaritin ( 1 ) and wushankaempferol ( 2 ), along with 24 known flavonoids were isolated from the whole herb of Epimedium wushanense T.S. Ying (Berberidaceae). On the basis of NMR and ESI-MS spectroscopic analysis, structures of compounds 1 and 2 were elucidated as 8-γ-hydroxy-γ,γ-dimethylpropyl-3,5,7-trihydroxy-4′- methoxyflavone and kaempferol 3- O -α- l -[2,3-di- O -β- d -(6- E - p -coumaroyl) glucopyranosyl]-rhamnopyranosyl-7- O -α- l -rhamnopyranoside, respectively. DPPH radical scavenging activity tests indicated that 1 (IC 50 35.3 μM) exhibited antioxidant activity comparable to Vitamin C (IC 50 32.0 μM), while 2 (IC 50 443.7 μM) showed weak activity.