桑叶总黄酮的提取及其抑菌活性研究

以抑菌活性为评价指标,对桑叶总黄酮的提取工艺进行了优化,并对优化条件下得到的粗提物采用不同溶剂进行分级提取和定性分析,测定了各萃取物的总黄酮含量,考察了萃取物对大肠杆菌、金黄色葡萄球菌的抑菌圈直径、最低抑菌浓度,选取抑菌效果最佳的萃取物进行了稳定性实验。结果表明,桑叶总黄酮提取的最佳条件为:温度70℃,乙醇体积分数70%,提取时间4 h,固液比1∶30(g∶mL);抑菌效果最佳的为乙酸乙酯萃取物,且乙酸乙酯部分对温度和紫外线照射的影响均具有良好的稳定性。

Extraction of Total Flavonoids of Mulberry Leaves and Their Antibacterial Activities

The extraction process of total flavonoids from mulberry leaves was optimized based on antibacterial activity.The curde extract obtained at the optimal condition was fractionated by different solvents and then qualitatively analyzed.The contents of total flavonoids of fractionated extracts were determined.The diameter of antibacterial circle and minimum inhibitory concentration of extracts on Escherichia coli(Ec.) and Staphyloccocus aureus Rosenbach(Sa.) were investigated.The stability of the better fractionated extract was tested.The results showed that the optimal extraction condition for curde extract is 70 ℃,70 % ethanol concentration,4 h and solid-liquid 1 ∶ 30(g ∶ mL).The fractionated extract being better antibacterial effect was ethyl acetate extract.Furthermore,ethyl acetate extract had better stabilities on temperature and UV irradiation.