超声辅助离子液体提取藜麦麸皮总皂苷及其抑菌活性研究

Extraction and Antibacterial Activities of Saponins from Quinoa Wheat Bran by Ultrasound-Assisted Ionic Liquids

采用超声波辅助离子液体(IL-UAE)提取藜麦麸皮中的总皂苷。考察了一系列阳离子组成不同的1-烷基-3-甲基咪唑离子液体的提取得率,并通过单因素与响应面实验探究料液比、离子液体浓度和提取时间及其交互作用对藜麦皂苷得率的影响,对IL-UAE的超声参数进行了优化。结果表明:超声辅助离子液体提取法提取藜麦麸皮总皂苷的最佳工艺条件为离子液体浓度0.51 mol/L、料液比1:38、提取时间21 min,在此条件下,总皂苷得率可达14.150%。通过牛津杯实验、抑菌率、最低抑菌浓度(MIC)和最低杀菌浓度(MBC)的测定对藜麦皂苷进行抑菌活性评价。结果表明,藜麦皂苷对大肠杆菌、鼠伤寒沙门氏菌、肠炎沙门氏菌和猪霍乱沙门氏菌均有一定的抑菌作用,且抑菌活性与浓度呈正相关。研究结果提示,超声辅助离子液体法是皂苷的高效提取方法,藜麦麸皮皂苷对肠道致病菌具有一定的抑菌活性。

Ultrasonic-assisted ionic liquid (IL-UAE) was used to extract total saponins from quinoa bran.The extraction rates of a series of 1-alkyl-3-methylimidazole ionic liquids with different cation compositions were investigated.The effects of solid-liquid ratio,ionic liquid concentration,extraction time and their interaction on the yield of quinoa saponin were investigated by single factor and response surface experiments.The ultrasonic parameters of IL-AE were optimized.The results showed that the optimal extraction conditions of total saponins from quinoa bran by ultrasonic-assisted ionic liquid were as follows:ionic liquid concentration 0.51 mol/L,solid-liquid ratio 1:38,extraction time 21 min.Under these conditions,the yield of total saponins could reach 14.150%.The bacteriostatic activity of quinoa saponin was evaluated by Oxford cup test,bacteriostatic rate,minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).The results showed that quinoa saponin had certain antibacterial activity against Escherichia coli,Salmonella typhimurium,Salmonella enteritidis and Salmonella cholera,and the antibacterial activity was positively correlated with the concentration.In conclusion,ionic liquid is an excellent extractant for ultrasonic-assisted extraction and has a broad prospect in the preparation of quinoa saponins.Quinoa bran saponin has certain antibacterial activity aganist enteropathogenic bacteria.