Research on the Extraction Technology of the Total Flavonoids from Lotus Leaf

[Objective] The technical support for the development and utilization of lotus leaf ata large-scale was provided.[Method]The total flavonoids in lotus leaf were extracted with the ultrasound-assisted extraction method;its content was deter mined with spectrophotometric method and the optimum extraction process was studied through the single factor and orthogonal experiment.[Results] When the ethanol concentration was up to 60%,the largest yield of total flavonoids could be extracted;when the ration of the solution to raw material was from 10∶1 to 30∶1,the yield of flavonoids was increased with the ratio-increasing of the solution to raw material and when the ration was at 40∶1,the yield of flavonoids tended to being stable.When the was 35 min,the maximum yield of flavonoids could be extracted,but compared with the treating time of 30 min,its yield was only slightly increased.The appropriate extracting temperature should be at 40 ℃.The order of the factors impacting extracting yield of total flavonoids was ethanol concentration ultrasonic time liquid ratio ultrasonic temperature.[Conclusion] The best extracting process of total flavones from lotus leaf was: the ratio of lotus leaf powder to solution,35∶1;the ethanol concentration,60%;the immersion time,24 h;the extracting time,35 min and temperature,35 ℃,so that the yield of total flavonoids extracted from lotus leaf was 13.68%.