The aim of this study was to analyze bioactivities of components extracted from Grifola frondosa that was grown in environmental controlled cultivation conditions. Ultrasonic extraction was used to extract ground powder from dry fruit body of Grifola frondosa by n-hexane, ethyl acetate and 50% ethanol. The extraction efficiencies of various organic solvents were 1.60 ? 0.36%, 3.10 ? 0.17% and 22.90 ? 0.40% for n-hexane, ethyl acetate and 50% ethanol respectively. DPPH radical scavenging activity, reducing power and ferrous ion chelating activity assays were used to analyze the bioactivity of various organic solvent extracts. Results showed that all extracts containing antioxidant activity. The components of various organic solvent extracts were detected by high-performance liquid chromatography-mass spectrophotometry (LC-MS/MS). Totally, seven peaks in ethyl acetate extract and n-hexane extract including S1-S7 were observed. Three antioxidant activity assays were used to determine the purified isolates. Results showed that S4 and S5 both have 90% DPPH radical scavenging activities with EC90=0.96 ? 0.02mg/ml for S4 and EC90=0.04 ? 0.02mg/ml for S5 respectively. Results of reducing power assay showed S4 had 36.08 ? 1.36% reducing power activitycompared with BHT, and the reducing power activity of S5 (>100%) which was higher than BHT. Interestingly, the crude ethyl acetate and n-hexane extracts of Grifola frondosa showed efficacy in ferrous ion chelating activities, but S1-S5 showed no efficacy in ferrous ion chelating activity. Finally, Lineweaver-Burk plots showed that S4 and S5 were both non-competitive inhibitors of L-Dopa for tyrosinase mediated oxidative activity.
