黄酮甙的酶解及其抗氧化活性的研究

【作者】 宾丽英；

【导师】 罗宗铭；

【作者基本信息】 广东工业大学 ， 应用化学， 2000， 硕士

【摘要】 合成食品抗氧化剂如BHT、BHA等已证实有损人体健康，寻求天然无毒、抗氧化性能好的食品抗氧化剂是当前研究的热点。黄酮类化合物由天然植物中提取，毒性小，具有许多生物活性，是最有发展潜力的天然多功能食品抗氧化剂。但因多数天然黄酮类化合物以黄酮甙存在，抗氧化能力较弱，妨碍了其应用。本文利用黑曲霉发酵产β—葡萄糖苷酶来水解黄酮式成甙元以提高抗氧化活性。 主要研究内容及实验结果有： 1、用95%乙醇从大豆中提取异黄酮，得率为0.67%，提取物含大豆甙 10.41%；用95%乙醇从葛根中提取大豆甙，层析纯化后提取物得率为 0.7%，含大豆甙47.2%；分别用热水从槐米中提取芦丁，黄芩中提取黄 芩甙，得率分别为5.3%、6.0%，其中槐米提取物含芦丁89.6%。 2、各提取物对猪油抗氧化实验结果发现，大豆和葛根提取物中大豆甙含量 越高，样品抗氧化活性越低。芦丁抗氧化活性比黄芩甙弱，比槲皮素更 弱。 3、比较4种菌种产β—葡萄糖苷酶情况，选定黑曲霉GIM3.25作为产酶菌 种，优化其产酶培养基后，使酶活从20.1U/ml提高到281U/ml。 4、用β—葡萄糖苷酶粗酶液酶解各种提取物及芦丁等黄酮甙，证明此粗酶 液能酶解所述黄酮甙成甙元。 5、将0.1%酶解前后各样品分别对猪油进行抗氧化实验，结果表明酶解后的 各样品抗氧化能力都有不同程度的提高，以芦丁、黄芩甙最为显著，可 与BHT媲美。 6、用CNDO法对芦丁和槲皮素、黄芩甙和黄芩素、橙皮甙和橙皮素、大豆 甙和大豆素、染料木素进行了计算，从理论上探讨了黄酮类化合物的抗 氧化机制。解释了黄酮甙抗氧化活性较其甙元弱的实验事实。更多还原

【Abstract】 Synthetical antioxidants ,such as BHT and BHA ,were improved to do harm to people抯 health. In order to seek the natural innoxious and effective antioxidants ,research was carried out as a hotspot today. Extracted from natural plants, flavones, which are the most potential natural multifunctional antioxidants, have little toxicity but lots of bioactivities. Most of natural flavones are in existance by flavoneglucosides which have faintish antioxidative and foreclose their applications. In order to increasing antioxidative of flavoneglucosides ,we carried out experiments to change flavoneglucosides to flavones by ~ - glucosidase produced by Aspergullus niger .The main contents and results are as follows: 1. Extracted isoflavone from soybean and Pueraria Lobata by 95% ethanol, the extraction contents daidzin 10.41% and 47.2%; extracted flavoneglucosides from Sophora Japonica and Scutellarica Baicalensis by hot water, the former extraction contents Rutin 89.6%. 2. The results of all extractions antioxidation in oil system showed that more daidzin in soybean and Pueraria Lobata extractions lower antioxidativities they represented. Quercetin was more effective than Rutin in oil oxidation system. 3. Choose Aspergullus Niger as ~ -glucosidase higherproducer. After optimaling its fermentation culture medium , ~ -glucosidase activity increased from 20.IU/ml to 28 lU/mi. 4. P -glucosidase hydrolyzing can made several extractions and flavoneglucoside change to relevant flavone. 5. Using 0.1% each fore-and-aft. enzyme hydrolyzing sample to do oil antioxidation experiment, results showed that antioxidativity of samples increased in different degree after enzyme action. After II enzyme hydrolyzing, the antioxidation effect of Rutin and Scutellarica Baicalensi flavone was notable and equivalent to BHT. 6. Applying method CNDO/2 to optimal and calculate the structures of flavonoids,~ including Rutin, Qcercetin ,dadzin , dadzein, Genistin and Genitstein et.al. Calculation results were used to discuss the antioxidation mechanism of flavones and explain the reason of the experiment facts that the flavoneglucoside antioxidative lower than flavonoids in oil oxidation system.更多还原