Antioxidant flavonoids from Epimedium wushanense

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-gamma-hydroxy-y-gamma,gamma-dimethylpropyl-3,5,7-trihydroxy-4'. methoxyflavone and kaempferol 3-O-alpha-L-[2,3-di-O-beta-D-(6-E-p-coumaroyl) glucopyranosyl]-rhamnopyranosyl-7-O-alpha-L-rhamnopyranoside, respectively. DPPH radical scavenging activity tests indicated that 1 (IC50 35.3 mu M) exhibited antioxidant activity comparable to Vitamin C (IC50 32.0 mu M). while 2 (IC50 443.7 mu M) showed weak activity. (C) 2011 Elsevier B.V. All rights reserved.