Abstract: In order to research the optimal ultrasonic extraction process and antipyretic effect of total flavonoids (TF)extracted from the fibrous root of Anemarrhena asphodeloides.Four main factors including ethanol concentration,ultrasonic extraction time,extraction times and ratio of material liquid were studied by using single factor experiment and response surface method.According to the mathematical model established by taking the four main factors into consideration,the best extraction technology was set as follows.The ethanol concentration was 70%,extraction time was 40 min,liquid to material ratio was 50 mL/g and the extraction times were 2 times.Yeast induced rat model was used to study the antipyretic effect of the total flavone extract and the contents of TNF-α,PGE-2,IL-6 and AVP in serum was determined to study the antipyretic mechanism.Compared with the model group,the body temperature of rats with fever decreased significantly,the content of TNF-α,PGE-2,IL-6 in serum and hypothalamus decreased significantly and the content of AVP in serum and hypothalamus increased significantly.It can be indicated that the total flavonoids from the fibrous root of Anemarrhena asphodeloides have antipyretic efficacy.Our conclusion could provide a useful reference for the comprehensive development and utilization of fibrous roots of Anemarrhena asphodeloides.

Key words: fibrous root of Anemarrhena asphodeloides, total flavonoids, extraction process, antipyretic effect