【作者】 张晓贤；

【导师】 苗芳；

【作者基本信息】 西北农林科技大学 ， 药用植物学， 2011， 硕士

【摘要】 决明子为豆科（Leguminosae）植物决明属（Cassia）的决明（Cassia obtusifolia L.）或小决明（Cassia tora L.）干燥成熟的种子,是常用的中药材。决明子含有蒽醌类、吡喃酮类、脂肪酸类、多糖类等化学成分。现代研究证明,决明子具有降压明目、调脂、保肝、抗氧化等作用,是保健食品、降脂减肥制剂和化妆品的原料。近年来,国内外对决明子的研究主要集中在决明子的化学成分、药理作用和临床应用、主要成分的提取分离以及含量测定等方面,同时对决明子的抗氧化活性也作了初步的研究。而关于决明子在萌发过程中抗氧化活性的动态变化规律还未见报道。本文以决明（Cassia obtusifolia L.）干燥种子和不同萌发期决明子苗的干粉为材料,采用超声波提取法提取醇溶成分和水溶成分,通过醇溶成分和水溶成分总抗氧化活性、还原力、清除羟自由基活性、清除过氧化氢活性和清除DPPH自由基活性的测定,研究了决明子萌发过程中抗氧化活性的变化规律;采用苯酚—硫酸法测定萌发过程中决明子苗水溶性多糖的含量,分析水溶性多糖含量的变化与水提物抗氧化活性的变化间的相关性。研究结果对决明子的进一步合理开发和有效利用提供理论指导。论文取得如下主要结论:（1）决明子种子本身和不同萌发期的决明子苗干粉醇提物和水提物均具有抗氧化活性。（2）在决明子萌发过程中,醇提物的总抗氧化活性呈先下降后上升再下降的趋势,还原力、清除DPPH自由基活性、清除羟自由基活性均呈先上升后下降的趋势。在种子萌发后第7天,醇提物的抗氧化活性达到最强且均高于干燥种子。（3）萌发后第7天的决明子苗醇提物的总抗氧化活性、还原力、清除羟自由基活性和清除过氧化氢活性明显弱于人工合成抗氧化剂BHT;清除DPPH自由基活性强于人工合成抗氧化剂BHT,清除DPPH自由基的IC₅₀（半抑制浓度）为0.80 mg/ml。（4）在决明子萌发过程中,水提物的总抗氧化活性和清除DPPH自由基活性呈下降趋势,还原力呈先下降后上升再下降的趋势,清除羟自由基活性呈先上升后下降的趋势。（5）在决明子萌发过程中,水提物多糖含量的变化与总抗氧化活性的变化、清除羟自由基活性的变化和清除过氧化氢的活性变化呈极显著正相关,与还原力变化呈负相关。更多还原

【Abstract】 Cassia seed is the dry mature seed of Cassia obtusifolia L. or Cassia tora L. belonging to leguminosae Jue Ming genera （Cassia）.. It is a common Chinese herbal medicine. It contains anthraquinones, pyranoid ketone, fatty acid, polysaccharides and so on. Modern research proved, Cassia seed has step-down and improving eyesight, adjusting lipid, protecting liver antioxidant effects and so forth. It is raw materials of health food, cosmetics, lipid-lowering and reducing weight drug. In recent years, the researches of Cassia seed at home and abroad are mainly concentrated in the chemical constituents,pharmacological functions, clinical applications, main component content of extraction and separation and so on, and at the same time the antioxidant activity also was made a preliminary study. Its antioxidant activity of dynamic change regulation in the process of germination has not been reported.Dry powder of Cassia seeds and their seedlings at different germination stages as the material. Ethanol-soluble components and water soluble components were extracted by ultrasonic method. The changes of antioxidant activity in the process of germination were evaluated by total antioxidant activity, reducing power, removing·OH activity, removing H₂O₂ activity and DPPH·clearance activity. Phenol - sulfuric acid methods was used to determine the content of water-soluble polysaccharide of Cassia seed seedling in the process of germination, meanwhile correlation was analyzed between the changes in contents of water-soluble polysaccharide and the changes in antioxidant activity of water extracts. And with synthetic antioxidants BHT （ butylated hydroxytoluene ） as controls, the potential of extracts of Cassia seed seedling as raw material of natural antioxidant was evaluated at multi-angles, as Cassia seed rational development and efficient use of available theoretical basis. Main findings were as follows:（1） Ethanol extracts and water extracts from dry powder of Cassia seeds and their seedlings at different germination stages all have antioxidant activity.（2） In the process of germination, ethanol extracts of total antioxidant activity was decreased and then increased again before declining trend; reducing power, DPPH·clearance activity, removing·OH activity increased first and then decreased. On the 7th days after seed germination, ethanol extracts antioxidant activity was higher than dry seeds.（3） Ethanol extracts on the 7th days after seed germination were weak in synthetic antioxidants BHT at Total antioxidant activity, reducing power, removing·OH activity and removing H₂O₂ activity. Its DPPH·clearance activity was stronger than BHT, and its IC₅₀ （50% inhibiting concentration） of removing DPPH·was 0.80 mg/ml.（4） In the process of germination, water extract of the total antioxidant activity and the DPPH·clearance activity decreased; reducing power was decreased and then increased again before declining trend, removing·OH activity was first increased and then decreased.（5） In the process of germination, the changes of polysaccharide contents and the changes of total antioxidant activity, removing·OH activity, removing H₂O₂ activity and DPPH·clearance activity were obvious positively correlated. The changes of polysaccharide contents were negatively related to the changes of reducing power.更多还原