Structure-Radical Scavenging Activity Relationships of Flavonoids from Ziziphus and Hydrangea Extracts

Abstract

Methanol extracts prepared from Ziziphus and Hydrangea fruits and leaves were examined for their antioxidant activity. Antioxidative activities were studied in sunflower oil at 980C, by measuring peroxide value, and with the spectrophotometric method, which uses 1, 1 diphenyl-2-picrylhydrazyl (DPPH) free radicals. The relationship between the structural characteristics of pure four flavonoids and their antioxidant activity was also studied. The obtained results suggest that the free radical scavenger potential of these polyphenolic compounds closely depends on the particular substitution pattern of free hydroxyl groups on the flavonoid skeleton.