柿叶黄酮超声辅助提取工艺及其抗氧化性研究

Study on the Extraction Technology by Ultrasonic Assisted and Antioxidant Activity of Total Flavonoids from Persimmon Leaves

研究超声波辅助提取柿叶总黄酮的工艺条件及其抗氧化活性。采用单因素试验与正交试验,考察乙醇浓度、固液比、超声功率、浸提温度及提取时间等因素对柿叶总黄酮提取率的影响,并以柿叶总黄酮体外清除DPPH自由基能力为指标,评价其抗氧化活性。结果表明,超声波辅助提取柿叶总黄酮最佳工艺条件为乙醇浓度为70%,固液比1∶20（g/mL）,超声功率350 W,超声时间40 min,浸提温度55℃,提取2次,柿叶总黄酮得率约为0.70%（以干柿叶计）;在0-100μg/mL范围内,柿叶总黄酮抗氧化能力高于VC,对DPPH自由基的体外清除率达85.96%;超过100μg/mL时,清除作用基本稳定不变,浓度和清除率不显示量效关系。通过拟合线性方程计算柿叶总黄酮的IC（50）值为5.45μg/mL,表明柿叶黄酮是良好的抗氧化剂。

The extraction technology by ultrasonic assisted and antioxidant activity of total flavonoids from persimmon leaves were studied. Single factor test and orthogonal test were made to study the effects of ethanol concentration, solid-liquid ratio, ultrasonic power, extraction temperature and extraction time on the extraction rate of total flavonoids from persimmon leaves and clearing DPPH radical scavenging ability in vitro of total flavonoids from persimmon leaves was taken as an index to evaluate the antioxidant activity. The results showed that the best condition for extraction technology by ultrasonic assisted from persimmon leaves was when ethanol concentration was 70%, solid-liquid ratio was 1∶20（g/mL）, ultrasonic power was 350 W, ultrasonic time was 40 min, soaking temperature was 55℃and extraction was made for 2 times, then total flavonoids from persimmon leaves could be 0.70%（calculated in dry persimmon leaves;in the scope of 0-100μg/mL,the antioxidant capacity of total flavonoids from persimmon leaves was higher than Vc, DPPH free radical scavenging rate was 85.96%;when it was over 100μg/mL, clear effect was basically stable, concentration and clearance did not show the relationship between quantity and effect. By fitting the linear equation of total flavonoids from persimmon leaves, the IC50 value was 5.45μg/mL, which showed that flavonoids from persimmon leaves were good antioxidants.