In: Arzneimittelforschung (1990 May) 40(5):589-93
In a randomized placebo controlled single-blind cross-over study of n = 10
apparently healthy subjects the influence of Ginkgo biloba (Kaveri) on blood
fluidity and cutaneous microcirculation was studied. Microcirculation was
measured before and every 30 min for 4 h after administration of Ginkgo biloba;
fluidity of blood was determined before and after 1, 2 and 4 h. Significant
changes in blood pressure or heart rate were found neither during Ginkgo phase
nor placebo phase. Haematocrit, plasma viscosity, erythrocyte rigidity,
thrombocyte and leukocyte count as well as thrombocyte aggregation and the
number of circulating thrombocyte aggregates were also not influenced by the
Ginkgo nor the placebo solution. In contrast a remarkable influence on the
erythrocyte aggregation was observed: comparing two samples a significant
decrease by 15.6% (p less than 0.001) with regard to the initial value was
observed after 2 h. The blood flow in the nail fold capillaries also increased
significantly by about 57% (p less than 0.004) 1 h after administration.
Bauer U
6-Month double-blind randomised clinical trial of Ginkgo biloba extract versus
placebo in two parallel groups in patients suffering from peripheral arterial
insufficiency.
In: Arzneimittelforschung (1984) 34(6):716-20
79 patients suffering from peripheral arteriopathy (Fontaine's stage IIb)
completed a 6-month double-blind randomised clinical trial of Ginkgo biloba
extract (GBE) (as coated tablets containing 40 mg GBE; rokan) versus placebo in
two parallel groups.
From the results of measurements of pain-free walking
distance, maximum walking distance and plethysmography recordings, GBE was shown
to be active and significantly superior to placebo. These results correlated
with the physician's and patients' overall assessment of response to treatment.
Hofferberth B
[The effect of Ginkgo biloba extract on neurophysiological and psychometric
measurement results in patients with psychotic organic brain syndrome. A
double-blind study against placebo]
Einfluss von Ginkgo biloba-Extrakt auf neurophysiologische und psychometrische
Messergebnisse bei Patienten mit hirnorganischem Psychosyndrom. Eine
Doppelblindstudie gegen Plazebo.
In: Arzneimittelforschung (1989 Aug) 39(8):918-22 (Published in German)
The range of typical symptoms of cerebro-organic syndrome such as dizziness,
memory and concentration loss, and orientation disorders can either be measured
objectively within a clinical trial or can be observed subjectively. Thirty-six
patients with classical symptoms of organic syndrome were recruited into a
placebo-controlled double- blind trial in which the therapeutic effect of Ginkgo
biloba extract EGb 761 (rokan) was measured by the following objective criteria:
quantified EEG, saccadic eye movements and psychometric tests (Wiener
Determination Test, Number Connection Test). Following 2 weeks' wash- out, 40
mg. EGb 761 was administered 3 times daily (= 120 mg daily dose) for 8 weeks.
The control group received placebo capsules of identical external appearance.
The tests listed above were carried out prior to treatment and after 4 and 8
weeks' therapy with the exception of quantitative EEG which was recorded at the
beginning and end of treatment only. Patients presenting with pathological
findings for at least two of the four test criteria were admitted to the trial.
Patients receiving unpermitted supplementary medication or suffering from acute
cardiovascular disturbances or digestive and metabolic disorders were excluded
from the trial. A highly significant difference could already been seen after 4
weeks of therapy and also after 8 weeks in the results of both the saccadic test
and the psychometric tests compared to the placebo control group. Saccade
duration was shortened and the latency reduced. In parallel, the number of
correct answers given in the Wiener Determination Test and Number Connection
Test increased significantly compared to the control group.
Hopfenmuller W
[Evidence for a therapeutic effect of Ginkgo biloba special extract.
Meta-analysis of 11 clinical studies in patients with cerebrovascular
insufficiency in old age]
Nachweis der therapeutischen Wirksamkeit eines Ginkgo biloba- Spezialextraktes.
Meta-Analyse von 11 klinischen Studien bei Patienten mit Hirnleistungsstorungen
im Alter.
In: Arzneimittelforschung (1994 Sep) 44(9):1005-13 (Published in German)
Eleven controlled clinical trials were evaluated in a meta-analysis in order to
proof the effectiveness of the ginkgo biloba special extract LI 1370 (Kaveri
forte). All included studies were placebo controlled randomized double blind
studies, using in most of the cases a daily dosage of 150 mg extract. The
requirements for the quality of the studies were the basic criteria for the
performance of clinical drug tests analysed from the biometrical scope. The
analysis of the individual studies revealed that three studies had to be
excluded from the meta-analysis according to methodological or objective
reasons. In two further studies the evaluation of the physician or the patients
was missing, therefore the studies could not be used for the analysis of the
"global effectiveness". All other studies were comparable with regard to
diagnoses, inclusion and exclusion criteria as well as methodology. Therefore a
statistical meta-analysis could be performed for them, analysing the parameters
"single symptoms", total score of clinical symptoms and "global effectiveness".
For all analyzed single symptoms significant differences could be concluded,
indicating the superiority of ginkgo biloba in comparison to placebo. The
analysis of the total score of clinical symptoms from all relevant studies
indicated that 7 studies confirmed the effectiveness (Ginkgo biloba being better
compared to placebo) while only one study was inconclusive (the medications were
not different). This relation confirms the therapeutical effectiveness of ginkgo
biloba regarding the clinical symptom complex.
Gessner B Voelp A Klasser M
Study of the long-term action of a Ginkgo biloba extract on vigilance and mental
performance as determined by means of quantitative pharmaco-EEG and psychometric
measurements.
In: Arzneimittelforschung (1985) 35(9):1459-65
The action of a Ginkgo biloba extract (rokan, Tanakan, G.B.E.) in promoting
blood flow has been demonstrated in several animal and human pharmacological
studies. The aim of this present study was to estimate the action of the
substance on the central nervous system in order to be able to assess its
potential use as a therapeutic agent in geriatric patients with cerebral
insufficiency. Quantitative pharmaco-EEG is the method of choice for studying
the vigilance- promoting effects of a drug. It is incomparable for confirming
the findings of behavioural and psychometric studies. 60 volunteers of either
sex participated in the double-blind trial. They were aged 57- 77 years and
showed mental deterioration corresponding to their age. They were randomly
divided into three experimental groups: 20 subjects received 3 X 40 mg/day
G.B.E., 20 received 5 mg nicergoline and 20 received a placebo of similar
appearance. The subjects underwent an extensive series of examinations before
and 4, 8 and 12 weeks after the start of medication. Analysis of the EEG results
for the whole group revealed no significant advantage of G.B.E. over the two
reference substances with regard to vigilance. However, a subclassification of
the subjects showed that the vigilance of those persons with a more unfavourable
initial situation measured in the resting EEG could be clearly improved by
chronic G.B.E. medication. This increase in vigilance was reflected at the
behavioural level by an improvement of reaction times in the G.B.E. group by
comparison with the reference substances.
*****BIOCHEMISTRY AND MOLECULAR BIOLOGY INTERNATIONAL*****
Shen JG Zhou DY
Efficiency of Ginkgo biloba extract (EGb 761) in antioxidant protection against
myocardial ischemia and reperfusion injury.
In: Biochem Mol Biol Int (1995 Jan) 35(1):125-34
The cardio-protective mechanisms of EGb 761, an extract of Ginkgo biloba leaves,
on myocardial ischemia-reperfusion injury were investigated using rabbits
subjected to 30 minutes of regional cardiac ischemia and 120 min of reperfusion
under anesthesia. Compared to the saline perfused group, EGb 761 treatment (10
mg/kg, injected into the coronary artery) significantly inhibited the increase
in lipid peroxidation and maintained total and CuZn-SOD levels in both plasma
and tissue during and at the end of reperfusion. Both the decrease in tissue
type plasminogen activator (t-PA) and the increase in plasminogen activator
inhibitor-1 (PAI-1) caused by ischemia-reperfusion were also significantly
suppressed by EGb 761 treatment. Furthermore, the ultrastructure of the myocytes
of the EGb 761 treated heart was slightly damaged after ischemia- reperfusion,
while the control ischemic-reperfused hearts demonstrated severe histological
damages such as swelling and vacuolization of the mitochondria.
These results
suggest that EGb 761 protects hearts by its antioxidant properties and by its
ability to adjust fibrinolytic activity.
*****BRITISH JOURNAL OF CLINICAL PHARMACOLOGY*****
Kleijnen J Knipschild P
Ginkgo biloba for cerebral insufficiency.
In: Br J Clin Pharmacol (1992 Oct) 34(4):352-8
1. By means of a critical review we tried to establish whether there is evidence
from controlled trials in humans on the efficacy of Ginkgo biloba extracts in
cerebral insufficiency.
2. The methodological quality of 40 trials on Ginkgo and
cerebral insufficiency was assessed using a list of predefined criteria of good
methodology, and the outcome of the trials was interpreted in relation to their
quality. A comparison of the quality was made with trials of co-dergocrine,
which is registered for the same indication.
3. There were eight well performed
trials out of a total of 40. Shortcomings were limited numbers of patients
included, and incomplete description of randomization procedures, patient
characteristics, effect measurement and data presentation. In no trial was
double-blindness checked.
Virtually all trials reported positive results, in
most trials the dosage was 120 mg Ginkgo extract a day, given for at least 4-6
weeks. For the best trials, there were no marked differences in the quality of
the evidence of the efficacy of Ginkgo in cerebral insufficiency compared with
co-dergocrine. The results of the review may be complicated by a combination of
publication bias and other biases, because there were no negative results
reported in many trials of low methodological quality.
4. Positive results have
been reported for Ginkgo biloba extracts in the treatment of cerebral
insufficiency.
*****CHEMICAL AND PHARMACEUTICAL BULLETIN*****
Itokawa H Totsuka N Nakahara K Maezuru M Takeya K Kondo M Inamatsu M
Morita H
A quantitative structure-activity relationship for antitumor activity of
long-chain phenols from Ginkgo biloba L.
In: Chem Pharm Bull (Tokyo) (1989 Jun) 37(6):1619-21
With the aim of obtaining compounds with strong antitumor activity, a
quantitative structure-activity relationship (QSAR) of antitumor phenolic
compounds (long-chain phenols) was derived using the Hansch- Fujita equation.
The ED50 values against Chinese hamster V-79 cells were analyzed in terms of log
P as the hydrophobic parameter and the energy of the lowest unoccupied molecular
orbital (ELUMO) calculated by using the modified neglect of differential overlap
(MNDO) method as the electronic parameter, by means of multiple regression
analysis. It was found that the activities mainly depended on log P (an optimum
log P of 8.3) and a low-lying ELUMO value. 4- Undecylcatechol, selected on the
basis of the above results, exhibited strong antitumor activity against Sarcoma
180 ascites and P- 388 lymphocytic leukemia.
*****CLINICAL THERAPEUTICS*****
Allain H Raoul P Lieury A LeCoz F Gandon JM d'Arbigny P
Effect of two doses of ginkgo biloba extract (EGb 761) on the dual- coding test
in elderly subjects.
In: Clin Ther (1993 May-Jun) 15(3):549-58
The subjects of this double-blind study were 18 elderly men and women (mean age,
69.3 years) with slight age-related memory impairment. In a crossover-study
design, each subject received placebo or an extract of Ginkgo biloba (EGb 761)
(320 mg or 600 mg) 1 hour before performing a dual-coding test that measures the
speed of information processing; the test consists of several coding series of
drawings and words presented at decreasing times of 1920, 960, 480, 240, and 120
ms. The dual-coding phenomenon (a break point between coding verbal material and
images) was demonstrated in all the tests. After placebo, the break point was
observed at 960 ms and dual coding beginning at 1920 ms. After each dose of the
ginkgo extract, the break point (at 480 ms) and dual coding (at 960 ms) were
significantly shifted toward a shorter presentation time, indicating an
improvement in the speed of information processing.
*****CORONARY ARTERY DISEASE*****
Tosaki A Engelman DT Pali T Engelman RM Droy-Lefaix MT
Ginkgo biloba extract (EGb 761) improves postischemic function in isolated
preconditioned working rat hearts.
In: Coron Artery Dis (1994 May) 5(5):443-50
BACKGROUND: We studied the effect of preconditioning and Gikgo biloba extract
(EGb 761) in relation to the recovery of contractile function after global
ischemia in the isolated working rat heart.
METHODS: Hearts (n = 12 in each group) were randomly divided into five groups:
In group I, hearts were subjected to 30 min of normothermic global ischemia
followed by 30 min of reperfusion; in group II, they were subjected to one cycle
of preconditioning consisting of 5 min ischemia and 10 min reperfusion before
the induction of 30 min of ischemia and 30 min of reperfusion; group III hearts
underwent two cycles of preconditioning; group IV hearts underwent three cycles
of preconditioning; and group hearts underwent four cycles of preconditioning
before the onset of 30 min ischemia followed by 30 min of reperfusion.
RESULTS: Ventricular fibrillation (total) and ventricular tachycardia (no
preconditioning) both fell from 100% to 50% (P < 0.05) after four cycles of
preconditioning. In relation to ventricular fibrillation, preconditioning
significantly reduced the formation of oxygen free radicals, measured by
electron spin resonance spectroscopy (ESR), but recovery of cardiac function was
low in all preconditioned groups. Because of the relatively low incidence of
arrhythmias (50% ventricular fibrillation and 50% ventricular tachycardia) and
relatively low cardiac function in Group V, EGb 761, a free-radical scavenger,
was chosen to improve myocardial contractile function in preconditioned hearts.
Fifty and 100 mg/kg of EGb 761 (per os) significantly improved coronary flow,
aortic flow, left ventricular developed pressure (LVDP), and the first
derivative of LVDP (LVDdP/dtmax) in the four-cycle preconditioned group. Thus,
after 30 min of reperfusion, aortic flow was improved from 11.6 +/- 0.9 ml/min
to 19.7 +/- 1.2 ml/min (P < 0.05) with a dose of 50 mg/kg of EGb 761 and to 22.0
+/- 1.5 ml/min (P < 0.05) with a dose 100 mg/kg of EGb 761, in the four-cycle
preconditioned group. During reperfusion, the formation of free radicals was
reduced by approximately 50 and 60% using 50 mg/kg and 100 mg/kg of EGb 761,
respectively, when compared with the four-cycle preconditioned drug-free control
group.
CONCLUSION: We have demonstrated that EGb 761 can improve contractile function
after global ischemia in the isolated working rat heart by reducing the
formation of oxygen free radicals, and we have shown that this protection is
additive to that of ischemia-induced preconditioning.
*****CURRENT MEDICAL RESEARCH AND OPINION*****
Rai GS Shovlin C Wesnes KA
A double-blind, placebo controlled study of Ginkgo biloba extract ('tanakan') in
elderly outpatients with mild to moderate memory impairment.
In: Curr Med Res Opin (1991) 12(6):350-5
Thirty-one patients over the age of 50 years and showing a mild to moderate
degree of memory impairment entered a 6-month double-blind, placebo controlled,
parallel group design study to assess the effects of a standardized Ginkgo
biloba extract (containing 24% flavonoid glycosides and 6% terpenes) on
cognitive function. Patients were allocated at random to receive oral doses of
40 mg Ginkgo biloba extract or identical placebo 3-times daily. Assessments were
made at baseline and after 12 and 24 weeks of treatment using a range of
psychometric tests. Efficacy data were available for 27 patients (15 in the
placebo group and 12 in the active treatment group). Statistical analysis of the
data as compared to baseline suggests that Ginkgo biloba extract had a
beneficial effect on cognitive function in this group of patients. Performance
on the Digit Copying sub-test of the Kendrick battery was significantly improved
at both 12 and 24 weeks, while the median speed of response on a computerized
version of a classification task also showed a significant superiority over
placebo at 24 weeks.
Grassel E
[Effect of Ginkgo-biloba extract on mental performance. Double-blind study using
computerized measurement conditions in patients with cerebral insufficiency]
Einfluss von Ginkgo-biloba-Extrakt auf die geistige Leistungsfahigkeit.
Doppelblindstudie unter computerisierten Messbedingungen bei Patienten mit
Zerebralinsuffizienz.
In: Fortschr Med (1992 Feb 20) 110(5):73-6 (Published in German)
Problem: The effect of ginkgo biloba extract EGb 761 on basic parameters of
mental performance.
Patients: Seventy-two outpatients with cerebral
insufficiency at three test centers. Study design: Double-blind, randomized
placebo-controlled study of 24 weeks duration.
Test parameters: Psychometric
computer-aided examination of the short-term memory and basic learning rate.
Results: Statistically significant improvement in the shortterm memory after 6
weeks and of the learning rate after 24 weeks in the test substance group, but
not in the placebo group (longitudinal analysis).
The difference between the
test substance and placebo groups (horizontal analysis) reached statistical
significance in the 24th week.
Conclusions: Treatment with ginkgo biloba extract
EGb 761 improves mental/mnestic performance.
GINGKO FRAUDS
We have tested many Gingko formulas. All Gingko was NOT created equally!
Many had an unacceptable levels of pesticide contamination. Others did NOT mention the concentration (potency) on the label, which should read 24%. Not surprisingly, they were the much cheaper 5-10% concentration, or, worse yet, "Gingko Leaf" which is almost worthless. If the label does not read, "Wildcrafted", you can be almost sure the Gingko Biloba's growth was accellerated with potent fertilizers and pesticides.
The best source of wild crafted 24% Gingko Biloba is at 870-856-4152, M-F 8-3 C.S.T. Sixty, 60mg caps for about $5.00.
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