【作者】 高海峰；

【导师】 周立刚； 赵思峰；

【作者基本信息】 石河子大学 ， 植物病理学， 2011， 硕士

【摘要】 白皮锦鸡儿(Caragana leucophloea Pojark.)为豆科(Leguminosae)蝶形花亚科(Faboideae)山羊豆族(Galegeae)锦鸡儿属植物,主要分布在新疆、甘肃、内蒙古等地,具有丰富的营养价值,是荒漠牲畜骆驼和羊的牧草。本文主要对白皮锦鸡儿乙醇提取物及其不同溶剂萃取组分进行抗菌和抗氧化活性筛选,采用活性追踪分离的方法对乙酸乙酯萃取组分进行分离纯化,对分离到的化合物进行抗菌和抗氧化活性的测定,取得的结果如下：对白皮锦鸡儿的乙醇提取物、石油醚萃取组分、乙酸乙酯萃取组分、正丁醇萃取组分和水部分进行了抗真菌和抗氧化活性测定,结果表明白皮锦鸡儿乙醇提取物具有一定的抑菌作用,在各萃取组分中,乙酸乙酯萃取组分对供试病原真菌表现出较强的抑制作用,同时也表现出较强的抗氧化活性。采用三氯化铝显色法检测了白皮锦鸡儿提取物及不同极性萃取组分的黄酮含量,发现乙酸乙酯萃取组分黄酮含量较高,继而用高速逆流色谱进一步纯化黄酮,纯化后组分中黄酮含量是纯化前的5.26倍,表明使用该方法纯化黄酮具有一定的应用价值。在优化高速逆流色谱分离条件的基础上,获得一色谱峰,经鉴定为3-O-甲基山奈酚,纯度为96.78%。通过硅胶柱层析、Sephadex LH-20柱层析、结晶与重结晶等分离技术,从白皮锦鸡儿的活性部位乙酸乙酯萃取组分分离得到了3个化合物,并运用1H-NMR、13C-NMR等波谱技术对其进行了鉴定,其结构分别为：3-O-甲基山奈酚(3-O-methylkaempferol,1)、3-O-甲基槲皮素(3-O-methylquercetin,2)和槲皮素(quercetin,3)。以6种细菌、1种真菌为供试菌株,通过MTT-比色法和稻瘟菌孢子萌发法对白皮锦鸡儿各化合物进行了抗菌活性测定,结果表明化合物1、化合物2和化合物3对番茄青枯病菌具有很好的抑制作用,其最低抑制浓度分别为12.5μg/mL、25μg/mL和25μg/mL,其IC50分别为7.42μg/mL、12.10μg/mL和12.29μg/mL,化合物1对6种细菌的抑制活性明显好于化合物2和化合物3;化合物1、化合物2和化合物3对稻瘟菌孢子萌发也有一定的抑制作用,其IC50分别为56.56μg/mL、76.61μg/mL和49.8。采用DPPH清除率法和抑制β-胡萝卜素/亚油酸氧化法检测了白皮锦鸡儿各化合物的抗氧化活性,结果表明各化合物对DPPH和β-胡萝卜素/亚油酸均表现出一定的抗氧化能力,化合物3和化合物2表现出较好的抗氧化活性,对DPPH清除率的IC50分别为13.64μg/mL和14.3μg/mL;对抑制β-胡萝卜素/亚油酸氧化的IC50分别为9.87μg/mL和110.26μg/mL。本论文首次对白皮锦鸡儿抗菌活性成分进行了研究,化合物1、化合物2和化合物3系首次从白皮锦鸡儿中分离得到,同时对3个化合物进行了抗菌和抗氧化活性的测定。研究结果为阐明白皮锦鸡儿抗菌化合物和白皮锦鸡儿资源的开发利用提供依据。更多还原

【Abstract】 Caragana leucophloea Pojark. belongs to the genus Caragana, tribe Galegeae, subfamily Faboideae, family Leguminosae. It mainly distributes in the Provinces of Xinjiang, Gansu and Mongolia. The crude ethanol extract from the aerial parts of C. leucophloea along with its fractions with different polarities were prepared and evaluated for their antimicrobial activity and antioxidant activity. The antimicrobial compounds were separated from the ethyl acetate fraction based on bioassay-guided fractionation. The main results are as follows.The results showed that the crude ethanol extract exhibited significant antifungal activity. Of them, ethyl acetate fraction was found to have the strongest antifungal and antioxidant activity which suggested that the antifungal and antioxidant components with their moderate polarity mainly existed in the ethyl acetate fraction.The ethyl acetate fraction was found to have a high value of flavonoid content, so it was further purified with HSCCC in order to prepare crude flavonoid fraction. Eight fractions were collected according to the elution profile, the highest flavonoid content was determined in the peak 4 fraction (20.51%) which was 5.26-fold of the flavonoid content of the crude extract. After optimization of separation conditions, one peak was obtained and identified as 3-O-methylkaempferoI with its purity as 96.78%.By bioassay-guided fractionation, three compounds were isolated and purified by column chromatography on silica gel, sephadex LH-20 and recrystallization from ethyl acetate fraction. Based on the spectrum analysis of their 1H-NMR,13C-NMR data, the compounds were identified as 3-O-methylkaempferol (1),3-O-methylquercetin (2), and quercetin (3).The compounds were evaluated for MIC and IC50 values by micro-dilution assay for the antimicrobial activity. Compounds 1,2 and 3 showed stronger inhibitory activity against Ralstonia solanacearum with their MIC values of 12.5μg/mL,25μg/mL and 7.42μg/mL, IC50 values of 7.42μg/mL,12.10μg/mL and 12.29μg/mL. Compounds 1,2 and 3 also exhibited inhibitory activities on the spore germination of Magnaporthe oryzae, with IC50 values of 56.56μg/mL, 76.61μg/mL and 49.80μg/mL.The antioxidant activity of the compounds was measured by DPPH radical scavenging assay andβ- carotene/linoleic acid system assay. The results showed that the compounds 3 and 2 exhibited stronger antioxidant activity to scavenge DPPH radical with the IC50 values of 13.64μg/mL and 12.10μg/mL; at the same time, they also exhibited batter antioxidant activity to inhibitedβ- carotene bleaching with the IC50 values of 9.87μg/mL and 10.26μg/mL.This is the first time to study the flavonoids ant their antimicrobial and anoxidant activities from C. leucophloea. The results could provide additional data for future development and utilization of C. leucophloea in the future.更多还原