Diarylheptanoid and Flavonoid with Antioxidant Activity from Alnus japonica Steud on DPPH Free Radical Scavenging Assay

Alnus japonica Steud (Betulaceae) has long been used as a Korean traditional medicine for gastric disorders, hepatitis, and fatty liver. As a part of our study on the identification of secondary metabolites of naturally occurring bioactive compounds, we isolated 1,7-bis(4-hydroxyphenyl)-3,5-heptanediol (1), 5-hydroxy-1,7- bis(4-hydroxyphenyl)-3-heptanone (2), 5,3'-dihydroxy-7,4'-dimethoxyflavone (3) and 3,5,7,3',4'-pentahydroxyflavone (4) from the dichloromethane and ethylacetate-soluble fractions of Alnus japonica Steud. These compounds showed significant antioxidant activity in a concentration-dependent manner. The IC50 values of compounds 1, 2, 3 and 4 were 30.1, 37.4, 20.2 and 13.7 g/mL, respectively, through the scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl radical assay. KCI Citation Count: 1