[Seasonal and sexual variety of Ginkgo flavonol glycosides in the leaves of Ginkgo biloba L].

HPLC methods have been developed for the determination of Ginkgo flavonol glycosides in the Ginkgo biloba leaves obtained from May to November in the fallen leaves and in the leaves obtained from female and male trees. The method includes hydrolysis of the leaves and subsequent quantitative chromatographic assay of the aglycones, followed by calculation of Ginkgo flavonol glycosides content. The result shows that the leaves obtained in May have the highest content of 0.96%, and then the content decreases from May to August, and from August to November remains almost the same, that is 0.5% also. Fallen leaves have the lowest content of 0.44%. The content range is 0.96% to 0.44%. Male trees have higher content of glycosides than female trees.