Fig. 1.

Comparison of antioxidant activities of burdock root tea (BRT) and burdock methanol extract. BRT was produced by boiling burdock roots (1.00 mg/mL) roasted six times in water at 100°C for 60 min. Methanol extract of burdock roots was prepared by extracting burdock roots (1.00 mg/mL) roasted six times in methanol at 30°C for 24 h. Burdock root extracts were subjected to total antioxidant capacity assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (A), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (B), ferric reducing capacity (C), copper chelating activity (D), total polyphenol contents (E), and flavonoid contents (F). Values are expressed as the mean±standard deviation (n=6). ***P<0.001 versus methanol extract. AA, ascorbic acid equivalent; TE, Trolox equivalents; GAE, gallic acid equivalents; CE, catechin equivalents.