Antioxidant activity of burdock (Arctium lappa linne): Its scavenging effect on free-radical and active oxygen.

摘要

Of the solvents used for extraction, water yielded the greatest amount of extract that exhibited the strongest antioxidant activity. Water extracts of burdock (WEB) and hot water extracts of burdock (HWEB) exhibited comparable and marked activity oninhibition of linoleic acid peroxidation, indicating that heat treatment did not alter the antioxidant activity of WEB. WEB and HWEB produced significantly lower malondialdehyde (MDA) in linoleic acid and liposome model systems than did the control. Moreover, mixtures of tocopherol (Toc), WEB and HWEB exhibited a remarkable synergistic antioxidant effect in a liposome system: WEB and HWEB thus potentiated the action of Toc. Furthermore, WEB and HWEB displayed a marked inhibitory effect on lipid peroxidation of rat liver homogenate in vitro. WEB and HWEB exhibited an 80% scavenging effect on alpha,alpha-diphenyl-beta-picrylhydrazyl radical and marked reducing power, indicating that WEB and HWEB act as primary antioxidants. Both extracts at a dose of 1.0 mg exhibited a 60.4-65.0% scavenging effect on superoxide and an 80.5% scavenging effect on hydrogen peroxide. They also showed a marked scavenging effect on the hydroxyl radical. WEB and HWEB were also active as oxygen scavengers and as secondary antioxidants. It suggested that termination of free radical reactions and quenching of reactive oxygen species in burdock extracts are, in part, responsible for the antioxidant activity of burdock extracts.