Variation of Four Flavonol in Fructus sophorea at Different Growth Periods

To investigate the relationship between Quercetin,Genistein,Kaempferol and Isorhamnetin in Fructus sophorea at different growth periods in order to define the optimal harvesting time for different applying purpose,samples of F. sophorea were collected from blooms to seed stage. The content of four flavonol in the extracts obtained from F. sophorea was simultaneously determined by HPLC after hydrolysis. The content of Quercetin increased first and then decreased during the growthpetiods. The content was the highest in early July,which was over 12. 4%. Genistein was produced in mid-August,and the contents increased gradually and tended to stabilize In mid-October. The average content was about 5. 6%. The content of Kaempferol was the highest and over 6. 2% in mid-August. The content of Isorhamnetin was the highest in early July.The average content was about 1. 3%. Content of the four flavonol in F. sophorea varied at different development stages and different season. The results suggested that the harvesting time for extracting Quercetin and Genistein is in early of july,for extracting Kaempferol is in mid-August,for extracting Isorhamnetin is in mid-September and for extraction of total flavonoids should be picked in December.