超声辅助离子液体提取荷叶黄酮及其抗氧化活性

Ultrasonic Assisted Ionic Liquid Extraction of flavonoids from Lotus Leaf and Their Antioxidant Activities

摘要:

优化超声辅助离子液体提取荷叶黄酮工艺，并评价其抗氧化活性。以荷叶提取物为原料，在单因素试验基础上，以离子液体浓度、超声功率、超声时间为影响因素，黄酮提取率为评价指标，响应面法优化提取工艺，测定黄酮对 DPPH、·OH自由基的清除作用。最佳条件为0.9 mol·L-1的1-己基-3-甲基咪唑四氟硼酸盐（[C6mim]BF4）溶液作为提取溶剂，固液比1:25 g·mL-1，超声功率186W，超声时间24min，提取温度70℃，提取率为4.65%。抗氧化活性研究表明，质量浓度为1.6 mg·mL-1时，荷叶黄酮对DPPH、·OH自由基清除率分别为63.2%和55.4%，IC50分别为0.8847mg·mL-1和1.1445mg·mL-1，还原力测定吸光度为0.72Abs。该方法稳定可靠，可用于超声辅助离子液体提取抗氧化活性较强的荷叶黄酮

Abstract:

To optimize the ultrasonic extraction auxiliary ionic liquids extraction process for flavonoids from Lotus Leaf and to evaluate the anti-oxidant activity. With ionic liquid concentration，ultrasonic power and ultrasonic time as influencing factors，flavonoids yield as an evaluation index，the extraction process was optimized by response surface method on the basis of single factor test．Subsequently the scavenging effects of flavonoids on DPPH，·OH free radicals were determined．The optimal conditions were determined to be 0.9 mol·L-1 of 1-hexyl-3-methylimidazole tetrafluoroborate([C6mim]BF4）as extraction solvent, 1:25 g·mL-1 for solid- liquid ratio 0.9 mol·L-1 for ionic liquid concentration，186W for ultrasonic power，and 24min for ultrasonic time，and 70℃ for extraction temperature ,total flavonoids demonstrated the extraction rate of 4.65%. When the mass concentration was 1.6 mg·mL-1，the scavenging rates of DPPH and ·OH radical were 63.2% and 55.4%，and the corresponding half inhibitory concentration (IC50) was 1.512 mg·mL-1and 2.140 mg·mL-1，the absorbance of reducing power determination was 0.72Abs. This stable and reliable method can be used for the extraction for flavonoids with significant in vitro antioxidant activity from Lotus Leaf.