含二氢吡唑杂环黄酮衍生物的合成及抗氧化活性

Synthesis and Antioxidative Activities of Flavone Derivatives Containing Dihydropyrazole Moiety

目的设计、合成含有二氢吡唑杂环结构的黄酮类衍生物,并初步探讨其体外抗氧化活性。方法以邻苯二酚为起始原料合成先导化合物7-羟基黄酮,与1,2-二溴乙烷反应得到7-溴乙氧基黄酮再经与含有邻羟基苯取代的二氢吡唑类化合物缩合得到6个含有二氢吡唑杂环结构的黄酮衍生物。目标化合物的结构通过IR、~1H-NMR、^(13)C-NMR、ESI-MS和元素分析进行确证。测定了目标化合物清除超氧自由基(O2-·)、羟自由基(·OH)、亚硝基自由基(NO_2·)和2,2-二苯基-1-苦味酰基自由基(DPPH·)的活性及总还原能力。结果在0.5 mg·mL^(-1)时,多数目标化合物具有抗氧化活性,但均弱于对照维生素C的抗氧化作用。结论 7-(1-苯基-3-甲基-4,5-二氢吡唑-5-苯基)-氧乙氧基黄酮(化合物2a)对4种自由基的清除作用及其总还原能力均较强,可以进一步进行体内抗氧化活性研究。

OBJECTIVE To design and synthesize flavone derivatives containing dihydropyrazole moiety and investigate their an- tioxidative activities in vitro. METHODS 7-Bromoethoxy flavone was synthesized by the reaction of 7-hydroxy flavone with 1,2-dibro- moethane. Then six fiavone 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 concentra- tion of 0. 5 mg · mL - l 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-dihydro- pyrazole-5-phenyl）-oxyethoxy flavone （compound 2a） are all relatively strong. Its antioxidative activities in vivo can be further investigated.