Seasonal Variations of the Flavonoid Content from Ginkgo biloba Leaves.

An HPLC method for the separation and the quantitative determination of flavonol glycosides, acylflavonol glycosides, and biflavones in crude leaf extracts from GINKGO BILOBA is described. The results, expressed in percentage of rutine, kaempferol P-coumaroyl glucorhamnoside, and bilobetin showed a higher amount of acylflavonol glycosides in buds, of flavonol glycosides in spring leaves, and of biflavones in autumn leaves.