A study about extraction total flavonoids from lotus (Nelumbo nuficera Gaertn) leaf by ultrasonic assisted method

Total flavonoids from lotus (Nelumbo nuficera Gaertn) leaf by ultrasonic assisted extraction was studied. Rutin being used as a standard to determine the content of flavonoids by measuring the absorbance at 510nm. The regression equation was C=0.0925A+0.0063(R=0.9996). The better extraction process was defined by single factor test,as following:60%～80% ethanol,raw material and solution ratio was 1 ∶25～1 ∶35,extraction time 2030min,extraction temperature 30～40℃. Based on the above conditions,the optimum extraction process was obtained by single factor test and results were:70% ethanol as a solvent ,the ration of raw material and solution 1 ∶35,soak 4h,ultrasonic extraction 30min at 40℃. At last,content of total flavonoids from lotus leaf was 7.47%. Ultrasonic technology has the advantages of higher extraction rate,shorter extraction time and less solvents and power consumption.