RESUMO
OBJECTIVE: To design and synthesize flavone derivatives containing dihydropyrazole moiety and investigate their antioxidative activities in vitro. METHODS: 7-Bromoethoxy flavone was synthesized by the reaction of 7-hydroxy flavone with 1, 2-dibromoethane. Then six flavone derivatives containing dihydropyrazole moiety were synthesized by the condensation reaction of 7-bromoethoxy flavone with two types of O-phenyl substituted dihydropyrazole compounds. These new compounds were characterized by IR, 1H-NMR, 13C-NMR, ESI-MS and EA. Their antioxidation effects, such as scavenging effects on the superoxide radical (O2-), hydroxyl radical (·OH), DPPH· radical, nitroso radicals (NO2·) and the total reduction activities, were compared. RESULTS: At the concentration of 0.5 mg·mL-1 most of the title compounds had antioxidation effects, but their activities were weaker than that of vitamine C. CONCLUSION: The scavenging effects on four different radicals and the total reduction activity of 7-(1-phenyl-3-methyl-4, 5-dihydropyrazole-5-phenyl)-oxyethoxy flavone (compound 2a) are all relatively strong. Its antioxidative activities in vivo can be further investigated.