Abstract: The leaves of Lespeda.dunnii were dealt with different extraction reagents. The flavonoids extracted were proved to exsist in Lespeda.dunnii. by the characteristic coloration reactions of the flavaonoids in comparison to UV and visible spectrum shown between the extracted substance and rutin.The technological conditions were approached by single factor and orthogonal test for the extraction of the flavonoids from Lespeda.dunnii.The results showed that the optimum technological conditions are: temperature at 75℃, the extraction reagent of 75% ethanol, material to extraction reagent 1:30 and the extraction time 3.5h. The flavonoids ratio yield of extraction reaches 89.46%. In addition, The anti-oxidant capacity of the flavonoids from Lespeda.dunnii. was preliminarily studied, as well.

Key words: Lespeda.dunnii, flavonoids, extraction technological conditions, hydroxy free radical