Antioxidative Activity of Phenolic Compounds in Roasted Safflower (Carthamus tinctorius L.) Seeds

Antioxidative compounds contained in roasted safflower seeds were investigated. Six phenolic compounds, N-feruloylserotonin, N-(p-coumaroyl) serotonin, matairesinol, 8′-hydroxyarctigenin, acacetin 7-O-β-D-glucoside (tilianine) and acacetin were isolated and identified from the extract of seeds. The inhibitory effects of six phenolic compounds on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation induced by H₂O₂/FeSO₄in rat liver microsomes were determined. Two serotonins showed more potent DPPH radical scavenging activity, and a stronger inhibitory effect on the lipid peroxidation than that of α-tocopherol. In addition, acacetin and matairesinol also considerably inhibited lipid peroxidation, while 2-hydroxy- arctigenin and tilianine were inactive. These results suggest that phenolic compounds, including serotonins, lignans and flavonoids in the roasted safflower seeds can be used as potential dietary natural antioxidants.