FROM:
J Pharm Pharmacol 1999 (May); 51 (5): 535–541
Curtis-Prior P, Vere D, Fray P
Cambridge Research Institute,
School of Applied Sciences
The Chinese tree Ginkgo biloba or "maiden hair tree" is
extensively cultivated for the exploitation of the medicinal
properties of its leaves. From these, a well-defined extract
designated "EGb 761" has been
developed, which was commercialized initially as Tanakan,
Tebonin and Rokin; a similar product, Kaveri (LI 3170), also
exists. The major therapeutic applications for these
products are "cerebral insufficiency", other cerebral
disorders, neurosensory problems and peripheral circulatory
disturbances. Four primary concepts of action have been
proposed to explain the pharmacotherapeutic benefits of
EGb761; these are: vasoregulatory, cognition-enhancing,
stress- alleviating, and gene-regulatory. These actions are
believed to be realized through the principal active
ingredients, flavonoids and the terpenoids ginkgolides and
bilobalide acting simultaneously in concert, combination and
synergy, so-called polyvalent action. It has been proposed
that EGb761 may improve the memory of healthy volunteers,
and in an assessment meta-analysis of forty clinical
studies, it was reported that Ginkgo was able to improve the
twelve different symptoms comprising 'cerebral
insufficiency', all of which are manifest in the elderly.
These were supported in a second major study, using LI1370.
However, in both instances, the evidence was largely based
upon the results of self-assessment questionnaires.
Latterly, in a large double blind study of men and women
with the diagnosis of uncomplicated dementia who were
administered Ginkgo for a year, a further positive outcome
was claimed. In this study, patients were tested using ADAS-
cog, GERRI and CGIC. It is suggested that whilst these
different outcomes are compatible with (but do not affirm) a
clinical benefit resulting from the use of Ginkgo, the
application of a more objective system of assessment would
be able to provide firm proof. It is proposed, therefore,
that an objective, computer-based testing system for
assessment of clinical improvement in volunteers and
patients administered Ginkgo (such as CANTAB) would provide
the convincing evidence currently being sought by patients,
carers, physicians, legislators and the pharmaceutical
industry.