Seasonal Variation of Flavonoid Content in Ginkgo biloba L. Leaves in Xuzhou

In order to know the seasonal variation of the content of flavonoid in Ginkgo biloba L.leaves in female and male tree,determine the picking season of Ginkgo biloba L.leaves in Xuzhou.The flavonoid was extracted by ethanol-ultrasonic method,the contents of flavonoid in Ginkgo biloba L.leaves in different gender and growth season were abstracted and measured by by UV spectrophotometry after purification.The results showed that the content of flavonoid in Ginkgo biloba L.leaves in Xuzhou was the highest in May and August,the content of flavonoid in the leaves of male trees was higher than that of female trees in April and May,which was lower than that of female trees in other months.Comprehensive consideration,the suitable picking season of medical Ginkgo biloba L.leaves in Xuzhou was in late August,and female trees was better.