Antioxidant flavonoids and chlorogenic acid from the leaves of Eriobotrya japonica

The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DP PH (1,1-diphenyl-2-picrylhydrazyl) rad ical and lipid peroxidation produced when mouse liver homogenate was expose d to the air at 37 degrees C, using 2-thiobarbituric acid (TBA). The methan ol extract and its tractions of Eriobotrya japonica leaves showed strong an tioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fr actions were stronger than the others, and were further purified by repeate d silica gel, MCI gel CHP-20P, and Sephadex LH-20 column chromatography. An tioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH traction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2 alpha-hydroxyursolic acid from EtOAc f raction were isolated. Antioxidant flavonoids and chlorogenic acid also sho wed prominent inhibitory activity against free radical generation in dichlo rofluorescein (DCF) method.