Antioxidant activities of citrus herbal product extracts

Total phenolic content, DPPH free radical-scavenging activity, hydrogen peroxide-scavenging activity, ferrous ion-chelating activity and ferric-reducing antioxidant power (FRAP) of four citrus herbal products, Citri Reticulatae Pericarpium (CRP), Citri Reticulatae Viride Pericarpium (CRVP), Aurantii Immaturus Fructus (AIF) and Aurantii Fructus (AF) extracts were determined. EC50 values of DPPH radical-scavenging activities ranged from 0.1 mg/ml (AF) to 1.59 mg/ml (AIF). EC50 values of hydrogen peroxide-scavenging activities ranged from 0.08 mg/ml (AF) to 0.9 mg/ml (CRP). EC50 values of ferrous ion-chelating activities ranged from 0.8 mg/ml (AF) to 2.08 mg/ml (AIF). The differences in DPPH free radical-scavenging activity, hydrogen peroxide-scavenging activity, and ferrous ion-chelating activity of all citrus herbal product extracts were significant. AF had the highest antioxidant activity. In this study, citrus herbal product extracts did not have good reducing power.