Figure 1.

The bottom line (at AU 0.00) shows the reference standard with the labeled flavonol gylcosides: rutin, quercitrin, quercetin, kaempferol, and isorhamnetin. Note that the 5 different ginkgo products (A, B, C, D, E) have substantial variation in the amount of the various glycosides, as reflected by the height of the chromatogram peak. There was more than a 25-fold variation in some constituents between products. (Reproduced with permission from Dubber MJ, Kanfer I. High-performance liquid chromatographic determination of selected flavonols in Ginkgo biloba solid oral dosage forms. J Pharm Pharm Sci. Sep 24 2004;7(3):303–309)