Radical scavenging activity of flavonoids from Trollius chinensis Bunge

Objective: Flos trollii is considered as functional tea, as well as a traditional medicinal herb, in China. In this study, total phenolic and flavonoid contents of Flos trollii were determined by a colorimetric method. The antioxidative potential of the hydroalcoholic extract of Flos trollii (FTE, extracted by alcohol:water, 80:20) was also evaluated by various antioxidant assays. Methods: Chemiluminescence technique was used to determine the radical scavenging activities of FTE toward different reactive oxygen species, including superoxide anion (O-2 center dot), hydroxyl radical (OH center dot), lipid-derived radicals (R center dot), and singlet oxygen (O-1(2)). Results: FTE could effectively scavenge O-2 center dot, OH center dot, R center dot, and O-1(2) at an efficient concentration (EC50) of 46, 5.64, 5.19, and 3.97 mg/mL, respectively. Moreover, the radical scavenging activities of FTE were higher than those of ascorbic acid. Further, FTE had higher 1,1 diphenyl-2-picrylhydrazyl radical (DPPH) radical-scavenging activity with EC50 44 mg/mL, compared with butylated hydroxytoluenesynthetic antioxidant with EC50 52 mg/mL. Conclusion: All results indicated that FIE is a powerful antioxidant, deserving of better utilization of the extracted Flos trollii as antioxidants. (C) 2011 Elsevier Inc. All rights reserved.