Antioxidant and cognitive-enhancing activities of Arctium lappa L. roots in Aβ_1-42-induced mouse model

Many studies have shown that oxidative stress induced by hydrogen peroxide can lead to neuronal cell death. In this study, protective effects of the ethanol extract of A. lappa L. roots against oxidative stress in PC12 cells were measured by 2′, 7′-dichlorofluorescein diacetate and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Oxidative stress contributes to the memory deficits induced by Beta-amyloid_1-42 in mice. Treatment with the ethanol extract of A. lappa L. roots improved working and reference memory in mice in the Y-maze and passive avoidance tests. To detect the lipid peroxidation levels, malondialdehyde was measured. To purify the bioactive compound, active fractions and components of A. lappa L. roots were isolated by partitioning, open column chromatography, TLC, high-performance liquid chromatography, electron ionization mass spectrometry, and ¹H/¹³C-nuclear magnetic resonance. We identified the bioactive compound as quinic acid, which is a powerful antioxidant agent. Ultimately, the roots of A. lappa L. may become available as an antioxidant food for Alzheimer’s disease patients and those with other oxidative stress-induced disorders.