Study on extraction process of flavonoids from Litchi seed

Extraction of flavonoids from Litchi seed,refluxing,heating extraction and microwave extraction were studied,the influence of solvent concentration,temperature,microwave power,extracting time and stock ratio on yield were studied by orthogonal test,the optimal conditions were determined: total flavonoids yield was 6.76% under the following conditions 50% alcohol solution as solvent,temperature 80 ℃,time 1 h,stock ratio 1 ∶10,extracting for three times.The optimum heat extracting procedure was determined as follows:50% alcohol solution as solvent,temperature 70 ℃,time 1.5 h,stock ratio 1 ∶12,extracting for two times,and total flavonoids yield was 6.37%.The optimum microwave extracting procedure was determined as follows:60% alcohol solution as solvent,microwave power 700 W,time 2.5 h,stock ratio 1 ∶25,and total flavonoids yield was 6.86%.