Abstract: To compare the contents of flavonoid aglycones in the leaves of Ginkgo biloba L.from different species in the southwest of Hubei province and to discuss the influential factors of environment.RP-HPLC was used to determine the flavonoid aglycones.The contents of carbon,hydrogen and nitrogen were measured by elementar vario MICRO CUBE analyzer.The results showed that the contents of flavonoids and flavonoid aglycones varied greatly from different species.Ratio of flavonoid aglycones in the leaves of EnG15 and EnG23 were better than others.Furthermore,the flavonoids content and the corresponding nitrogen content was correlated positively.Appropriate nitrogen may help improve ratio of flavonoids component in the leaves of G.biloba. The results of this study may provide a basis for the optimization of the quality and resources of G.biloba.

Key words: Ginkgo biloba L., flavonoids, quercetin, kaempferol, isorhamnetin