ABSTRACT
Chemical Composition of EGb 761 341
In Vitro Effects of EGb 761 on Differential Gene Expression
in Neuronal Cells 344
In Vivo Effects of EGb 761 on Differential Gene Expression in the Brain 346
Conclusion 349
References 349
CHEMICAL COMPOSITION OF EGb 761
The leaves of Ginkgo biloba L. contain a variety of chemical compounds, some
of which are unique to this ancient tree. Various substances can be found in its
leaves, among which flavonoids and terpenoids are probably the most interesting
components (1-3). In dried Ginkgo leaves, the content of flavonoid glycosides
is 0.5-1% w/w, whereas the content of terpenoids is often ,0.1% w/w (2). The phenolic aglycone moiety of the flavonoid glycosides is made up pre-
dominantly of the flavonols quercetin or kaempferol, the occurrence of isorham-
netin being significantly smaller. Other flavonoids are found only in very small
amounts. The glycoside moiety consists of mono-or diglycosides (mainly
D-glucose and L-rhamnose units) that are connected to the aglycone via
O-b-glycosidic bonds. Some of these glycosides are additionally acylated by p-coumaric acid (Fig. 16.1). These latter compounds are distinctive to Ginkgo
biloba leaves and extracts (4,5).
