Abstract: Extraction technology of isflavones in Trifolium pratense was developed by using an obturated microwave-assisted extraction(MAE)equipment.Effects of ethanol-water solvent,microwave power,raito of liquid to material,extraction time and extraction times on extraction rate of isflavones were investigated by single factor and orthogonal test.The optimum extraction conditions for Trifolium pratense isflavones were established as follows:70% ethanol(V/V)as solvent,ratio of liquid to material 15:1(V/W),microwave power high fire(750W),extraction for 3 times and 1 min for each time.The extraction rate of isflavones in Trifolium pratense was as high as 98.91%.Compared with ultrasonic extraction,refluence extraction and Soxhlet extraction,microwave extraction is a rapid method with a good selectivity and handle expediently.

Key words: microwave extraction, Trifolium pratense, isoflavone, orthogonal test