摘要
以管萼山豆根的叶为原料,采用微波-超声波辅助低共熔溶剂(DES)提取总黄酮,筛选出较优的DES体系,在单因素试验的基础上,运用Plackett-Burman和响应面试验优化其提取工艺;并考察了最佳提取工艺下总黄酮对 DPPH·、·ABTS+和·OH 的清除作用.研究结果表明:较优的 DES 溶剂体系为n(氯化胆碱)∶n(三乙二醇)=1∶3,总黄酮的最佳提取工艺条件为提取时间45 min、提取温度74℃、料液比1∶45(g∶mL)、微波功率300 W、DES含水量25%、超声波功率300 W,在该条件下叶中总黄酮得率为3.460%;分别采用乙酸乙酯、热乙酸乙酯(50±1)℃、大孔吸附树脂AB-8、NKA-9 和D101 分离总黄酮,其回收率分别为23.40%、28.09%、88.66%、71.55%和41.86%;AB-8 大孔树脂分离所得总黄酮对DPPH·、·ABTS+与·OH的半数抑制质量浓度(IC50)值分别为 0.017 05、0.018 35和0.123 30 g/L;总黄酮对DPPH·、·ABTS+的清除率显著高于维生素C(Vc),而对·OH的清除率略低于Vc.进一步分析发现:优化条件下叶总黄酮得率(3.460%)高于茎(2.059%)和根(1.875%),高于单一微波提取(3.377%)和超声波提取(3.390%),低于加热回流提取(3.635%),但所需时间仅为加热回流提取的1/4.
Abstract
Microwave-ultrasonic assisted deep eutectic solvent(DES)was used to optimize the extraction conditions of total flavonoids from the leaves of Euchresta tubulosa Dunn and the optimal DES were selected.On the basis of single factor experiment,Plackett-Burman and response surface experiments were used to optimize the extraction process.The scavenging effects of the total flavonoids on DPPH·,·ABTS+and·OH under the optimal extraction process were investigated.The results showed that the optimum solvent system was n(choline chloride)∶n(triethylene glycol)=1∶3.The optimum extraction conditions were as follows:extraction time was 45 min,extraction temperature was 74℃,solid-liquid ratio was 1∶45,microwave power was 300 W,DES water content was 25%and ultrasonic power was 300 W.Under these conditions,the yield of total flavonoids in leaves was 3.460%.Total flavonoids were separated by ethyl acetate,hot ethyl acetate(50±1)℃,AB-8,NKA-9 and D101 macroporous adsorbent resins,with the recovery rates were 23.40%,28.09%,88.66%,71.55%and 41.86%,respectively.The half inhibitory mass concentration(IC50)values of total flavonoids isolated by AB-8 macroporous resin on DPPH·,·ABTS+and·OH were0.017 05,0.018 35 and 0.123 30 g/L,respectively.The scavenging rate of DPPH·and·ABTS+by total flavonoids was significantly higher than that of vitamin C(Vc),while the scavenging rate of·OH was slightly lower than that of Vc.Further analysis showed that under optimized conditions,the yield of total flavonoids from leaves(3.460%)was higher than those of stems and roots(2.059%and 1.875%),higher than those of single microwave extraction and ultrasonic extraction(3.377%and 3.390%),lower than that of heating reflux extraction(3.635%),while the time was only 1/4 of that of refluxing extraction.
基金项目
国家自然科学基金(31760084)
广东省植物资源生物炼制重点实验室开放基金(2021GDKLPRB03)
湖南省中医药科研重点项目(A2023045)
维普
万方数据