摘 要：分别用乙醇、水、KOH从芡实中提取乙醇提取物和三种不同沉淀物（I,II, 和 III），目的是评价它们的抗氧化组合效应。探究沉淀物中的黄酮，总酚和多糖，并测试提取物的抗氧化活性。实验结果表明，用Folin-Cioalteau酚试剂测得乙醇提取物中总酚含量为29。1±1。2mg/g，总黄酮含量为38。6±4。2mg/g。用GC-MS测得沉淀物 I 主要成分为直链淀粉和非淀粉多糖（葡萄糖41。9%，木糖12。3%，半乳糖8。16%），沉淀物II主要成分为支链淀粉，用碘淀粉比色法测得沉淀物III的主要成分为直链淀粉。对羟自由基的清除效果为：乙醇提取物>VC>I>II>III；对O2- 和DPPH的清除效果为：VC>I>乙醇提取物>II>III。此研究表明芡实有良好的抗氧化活性，进一步推测出芡实的抗氧化作用是黄酮、酚类化合物和多糖具体作用结果。79156

毕业论文关键词：芡实,黄酮,总酚,多糖,抗氧化活性

Abstract :The present investigation is aimed to evaluate the antioxidative combined effects of an ethanolic and three distinct precipitates (I,II, and III) extracts from Gordon euryale seeds using ethanol, water, and KOH。 Total flavonoids, phenolics of ethanol extract, and polysaccharides of precipitates were detected。 The antioxidant activity of extracts were assayed。 The results showed that ethanol extract contained a phenolic content of 29。1±1。2mg/g, and a total flavonoid content of 38。6±4。2mg/g using Folin–Ciocalteau phenol。 Precipitates I was composed mainly of amylose and non-starch polysaccharides (glc, 41。9%; xyl,12。3% and gal,8。16%) by GC-MS, II was composed mainly of amylopectin, and III was composed mainly of amylose with a colorimetric Iodine Starch Assay。 The scavenging activity of extracts were, for ۰OH, ethanol extract > ascorbic acid Vc > I > II > III; O2-۰and DPPH۰, Vc > I > ethanol extract > II > III。 This study showed that Gordon euryale seeds have good antioxidant qualities, and further deduced that the antioxidant function of Gordon euryale seeds was the result of the specific role of flavonoids, phenolics, and polysaccharides。

Keywords: Gordon euryale seeds,Flavonoids, Phenolics,Polysaccharide,Antioxidant activity

目  录

1 引言 4

2材料和方法 4

2。1实验仪器 4

2。2化学药品 4

2。3 植物采集 5

2。4 提取物 5

2。4。1 黄酮的提取 5

2。4。2 多糖的提取 5

2。5 各成分的植物化学分析 5

2。5。1总酚的测定 5

2。5。2总黄酮含量的测定 6

2。5。3 多糖含量的测定 6

2。6 自由基清除能力 6

2。6。1 DPPH法 6

2。6。2超氧阴离子自由基清除实验 7

2。6。3羟基自由基清除实验 7

2。7数据分析 7

3 结果与讨论 8

3。1乙醇提取物的产量、总酚和总黄酮含量 8

3。2沉淀物Ⅰ、Ⅱ和Ⅲ的产量和化学成分 8

3。3 抗氧化活性