Study on the extraction method and antioxidant activity of flavonoids from Sophora japonica L.

The study aimed to explore the flavonoids contents and antioxidant activity of diffrerent extracts from Sophora japonica L by ultrsonoc-assisted aqueous two-phase extraction ( UATPE) , reflux extraction ( RE) , Semibionic extraction ( SBE) , water extraction ( WE) , Ultrasonic assisted aqueous two- phase ( alkaline UATPEA) , respectively.The results indicated that the content of flavonoids extracted by RE was the highest, which showed a significant difference ( p < 0.05) compared with other methods except for UATPE ( p > 0.05) .The antioxidant results showed that flavonoids extracts by the five different methods obtaining had strong antioxidant activity.The scavenging ability of DPPH free radical and reduction of copper ions of flavonoids extracted by UATPE was the strongest.In addition, ABTS radical scavenging effect and iron ion chelating power of UATPEA flavonoids extractes were better than that of other methods.Moreover, the extracts obtained by different methods inhibition linoleic acid was RE > UATPE > SBE > UATPEA > WE. The results indicated that the flavonoids in Sophora japonica L were soluble in organic solvent.The extracts obtained by UATPE had better antioxidant activity.