Biflavone glucosides from Ginkgo biloba yellow leaves.

Phytochemical investigation of Ginkgo biloba (Ginkgoaceae) has resulted in the isolation of two new biflavone glucosides, ginkgetin 7''-O-beta-D-glucopyranoside (1) and isoginkgetin 7-O-beta-D-glucopyranoside (2). The structures were determined on the basis of chemical and spectroscopic evidences.