Free radical scavenging activity of an aqueous extract of potato peel

The antioxidant potency of freeze-dried aqueous extract of potato peel was investigated employing various established in vitro systems, such as lipid peroxidation in rat liver homogenate, 1, 1-diphenyl-2-pierylhydrazyl (DPPH)/superoxide/hydroxyl radical scavenging, reducing power, and iron ion chelation. Freeze-dried aqueous extract of potato peel powder (PPE) showed strong inhibitory activity toward lipid peroxidation of rat liver homogenate induced by the FeCl2-H2O2 system. Furthermore, PPE exhibited a strong concentration-dependent inhibition of deoxyribose oxidation. PPE also showed a considerable antioxidant activity in the DPPH radical assay system. The multiple antioxidant activity of PPE was evident as it showed strong reducing power, superoxide scavenging ability and also ferrous ion chelating potency. The data obtained in the in vitro models clearly establish the antioxidant potency of freeze-dried extract of potato peel. Considering that potato peels are discarded as waste and not effectively utilized, these in vitro results suggest the possibility that potato peel waste could be effectively employed as an ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models. (C) 2003 Elsevier Ltd. All rights reserved.