【作者】 李小飞；

【导师】 李冠；

【作者基本信息】 新疆大学 ， 生物化学与分子生物学， 2007， 硕士

【摘要】 本研究对自由基氧化作用与疾病以及其与食品氧化腐败的关系做了简要综述,对天然抗氧化产物方面的研究以及目前鸢尾属和喜碱鸢尾化学成分方面的研究都做了总结。喜碱鸢尾根95%乙醇提取物的预示实验显示:其主要含有黄酮类、酚性成分、多糖、有机酸等成分。用二苯代苦味酰自由基（DPPH）分光光度法对喜碱鸢尾根95%乙醇提取物不同萃取组分的自由基清除能力进行了研究,分别用半数清除量(EC₅₀)和清除效率（AE）两个参数评价不同组分的自由基清除能力,并与BHT做比较,同时用紫外光谱进行定性研究。结果显示:各个组分均有一定的自由基清除活性,各组分EC₅₀大小顺序为:BHT >正丁醇部分>水部分>乙酸乙酯部分, AE的大小顺序为:正丁醇部分>BHT>水部分>乙酸乙酯部分,正丁醇部分对DPPH的清除效率高于BHT,具有很好的抗氧化活性。由紫外吸收光谱得出:各部分样品中的主要化合物为异黄酮类化合物。通过各种色谱技术对乙酸乙酯部分进行分离纯化研究,首次从该植物分离得到四个化合物单体,用UV、IR、MS、NMR、X-ray技术鉴定了四种化合物的结构,他们分别是:6,4’-二甲氧基-5,7-二羟基异黄酮、5,7,3’-三羟基-6, 4’,5’-三甲氧基异黄酮、5,4’-二羟基-6,7-亚甲二氧基异黄酮、5-甲氧基-4’-羟基-6,7-亚甲二氧基异黄酮、尤其用X-ray技术对5-甲氧基-4’-羟基-6,7-亚甲二氧基异黄酮的空间结构,包括分子内部各键长、键角、以及分子内氢键等信息进行了详细研究,并且对该化合物的晶体结构信息注册于英国国际晶体剑桥数据库（CCDC）,注册号为CCDC: 645846。通过DPPH分光光度法发现四种化合物中,5,4’-二羟基-6,7-亚甲二氧基异黄酮对DPPH自由基有很好的清除活性,但是其清除活性却不及BHT,其余三种化合物对DPPH自由基的清除活性较低。更多还原

【Abstract】 The relations of oxidation and disease, food rot were reviewed, researches on natural anti-oxidative products and chemical compounds from Iris L.and Iris.halophila Pall. were also summarized in this thesis.The predictive-analysis test showed that the main components in 95% ethanol extract are flavones、phenolic compounds、amylose、organic acid。The 95% ethanol extract of I.halophila Pall. root was divided into ethyl-acetate fraction, n-butanol fraction, aqueous fraction and petroleum-ether fraction, the anti-oxidative activities of different fractions except petroleum-ether fraction were analyzed by DPPH means and estimated by EC₅₀ and AE parameters which were compared with BHT’s, UV absorption spectrum was also used to analyze the main components in these fractions. As a result, three fractions all have DPPH radical scavenging activity, the order of EC₅₀ is BHT>n-butanol fraction>aqueous fraction> ethyl-acetate fraction, meanwhile the order of AE is n-butanol fraction >BHT> aqueous fraction > ethyl-acetate fraction, it was indicated that n-butanol fraction has better antiradical efficiencies（AE） than BHT’s, the UV absorption spectrum indicated that the main components in every fraction are iso-flavones.Four compounds were isolated from ethyl-acetate fraction by using chromatography technology, and they are first isolated from I.halophila Pall., the structures of the four compounds were identified by using UV、IR、MS、NMR and X-ray diffraction technologies. The four compounds are 6,4’-dimethoxy-5,7-dihydr-oxy-isoflavone;5,7,3’-trihydroxy-6,7,4’-trimethoxy-isoflavone（Irigenin）;5,4’dihydroxy-6,7–methylenedioxy-isoflavone（Irilone） and 5-Methoxy-4’-hydroxy-6,7-methy-lenedioxy-iso-flavone（Nigrigin）.Nigri- gin was characteri-zed by single-crystal X-ray diffraction, bond lengths and bond angle of Nigrigin molecular were studied by X-ray diffraction. The detail document of Nigrigin molecular was registered in Cambridge Crystallograp- hic Data Centre（CCDC）, the registered number is: 645846.Anti-oxidative activity of the four compounds were analyzed by DPPH means, the result is that the activity of 5,4’-dihydroxy-6,7-methyllenedioxy- isoflavone is better than other three compounds, but lower than BHT’s.更多还原