Kimbel KH

Ginkgo biloba [letter; comment]

In: Lancet (1992 Dec 12) 340(8833):1474

Kleijnen J Knipschild P

Ginkgo biloba [see comments]

In: Lancet (1992 Nov 7) 340(8828):1136-9

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. The clinical evidence is similar to that of a registered product which is prescribed for the same indication. However, further studies should be conducted for a more detailed assessment of the efficacy.

Kleijnen J Knipschild P

The comprehensiveness of Medline and Embase computer searches. Searches for controlled trials of homoeopathy, ascorbic acid for common cold and ginkgo biloba for cerebral insufficiency and intermittent claudication.

In: Pharm Weekbl Sci (1992 Oct 16) 14(5):316-20

OBJECTIVE: To assess the comprehensiveness of Medline and Embase computer searches for controlled trials. DESIGN: Comparison of articles found after an exhaustive search of the literature with the yield of a Medline or Embase search. This was performed for controlled clinical trials on the efficacy of three interventions: homoeopathy, ascorbic acid for common cold, and ginkgo biloba for intermittent claudication and cerebral insufficiency. The number of controlled trials found by exhaustive search of the literature was 107, 61 and 45, respectively. RESULTS: For homoeopathy, ascorbic acid and ginkgo the proportion of all trials found by Medline was 17%, 36% and 31% respectively and for Embase 13%, 25% and 58% respectively. After checking of the references in the Medline articles 44%, 79% and 76% of all trials were identified. After checking of the references in the Embase articles 42%, 72% and 93% of all trials were identified. About 20% of the articles was not correctly indexed. Of the best trials 68%, 91% and 83% could be found with Medline and 55%, 82% and 92% of the best trials were identified through Embase. CONCLUSIONS: For the topics mentioned, Medline and Embase searches are sufficient to get an impression of the evidence from controlled trials, but only if references in the articles are followed for further evidence. If one wants to get a more complete picture, additional search strategies make sense. Of course, this picture may be different for other topics.

Kobayashi N Suzuki R Koide C Suzuki T Matsuda H Kubo M

[Effect of leaves of Ginkgo biloba on hair regrowth in C3H strain mice]

In: Yakugaku Zasshi (1993 Oct) 113(10):718-24 (Published in Japanese)

Effects of 70% ethanolic extract from leaves of Ginkgo biloba (GBE) on the hair regrowth in normal and high butter diet-pretreated C3H strain mice which posterior hair we shaved were investigated. GBE showed a promoting effect on the hair regrowth. GBE had the inhibitory effects on blood platelet aggregation, thrombin activity and fibrinolysis. GBE inhibited the increase of serum the triglyceride level in high cholesterol diet-treated rats. These results suggested that GBE promotes the hair regrowth and could be used as a hair tonic.

Koltringer P Langsteger W Klima G Reisecker F Eber O

[Hemorheologic effects of ginkgo biloba extract EGb 761. Dose- dependent effect of EGb 761 on microcirculation and viscoelasticity of blood]

In: Fortschr Med (1993 Apr 10) 111(10):170-2 (Published in German)

Method: In a randomized open clinical trial involving 42 patients with pathological visco-elasticity values, the effect of a single intravenous injection of 50, 100, 150 or 200 mg of the Ginkgo biloba extract EGb 761, commercially available as Tebonin p.i. on the microcirculation of the skin (Doppler flowmetry) and the visco- elasticity of whole blood was investigated. Results: A dose-dependent significant increase in the microcirculation was found. In the case of visco-elasticity, this dose-dependence was less marked. The present study thus confirms the positive effect of EGb 761 on the microcirculation and whole-blood visco-elasticity in patients with pathological visco-elasticity values, already found in earlier studies, and shows it to be dependent on the dose employed.

Krauskopf R., Guinot Ph., Peetz H.G.:

Long term on line EEG analysei de monstrating the pharmaco-dynamic effect of a defined Ginkgo biloba extract.

In: Beaufour -Schwabe Internat. Report, 1983.

Kunkel H

EEG profile of three different extractions of Ginkgo biloba.

In: Neuropsychobiology (1993) 27(1):40-5

Two experiment were conducted to assess the electroencephalographic effects of (1) three different dosages of a total extract of Ginkgo biloba (EGb 761, Tebonin) and (2) three different extractions of G. biloba (Tebonin and two fractions from it). The medicament was tested against placebo using a double-blind cross-over design in 12 normal healthy males for each experiment. Medication was administered for 3 days preceding the recording sessions. 25 parameters were computed from the EEG spectra. Medication-related effects were obtained for most of the power measures, whereas dominant frequencies of the respective frequency band remained largely unchanged. The differences between the EEG effects of the two studies are critically discussed.

Lee K Ku JR Koh SD Kim KS

Effects of methanol extract of ginkgo biloba (EGb), its ethylacetate fraction (EAF) and butanol fraction (BF) on the isolated aorta.

In: Jpn J Pharmacol (1992) 58 Suppl 2:377P

Long R Yin R Zhen Y

[Partial purification and analysis of allergenicity, immunogenicity of Ginkgo biloba L. pollen]

In: Hua Hsi I Ko Ta Hsueh Hsueh Pao (1992 Sep) 23(4):429-32 (Published in Chinese)

Pollens of Ginkgo biloba L. (G.b.l.p) have been found to be a kind of important allergen which causes pollinosis in Chengdu. The goal of this study is to purify G.b.l.p and to determine the allergenicity and immunogenicity of various fractions. Crude extract was purified by gel filtration with Sephadex G25, then G75. Two elution peaks were observed. On SDS-PAGE, the molecular weights of protein of the 1st peak and the valley were 30-42 kd and 13-18kd, respectively, and that of the 2nd peak was less than 13 kd. 40 patients with allergic rhinitis and/or asthma underwent the skin test with crude extract and various fractions of gel filtration; it revealed that the strongest allergenic activity existed in the 1st peak and there was mild allergenic activity in the 2nd peak. The in vitro allergenic activity and immunogenic activity of various fractions were examined by ELISA inhibition test. It was further confirmed that the allergenic activity and immunogenic activity of the 1st peak were the strongest, and those of the 2nd peak were the lowest. It is suggested that diagnosing reagents can be made satisfactorily by partial purification, i.e. discarding the inactive fractions, since allergenicity exists in various fragments. But fractions of allergen with high IgG immunogenicity should be selected to produce immunotherapy agents so as to enhance the production of blocking antibody and thus improve the therapeutic effect.

Marcocci L Maguire JJ Droy-Lefaix MT Packer L

The nitric oxide-scavenging properties of Ginkgo biloba extract EGb 761.

In: Biochem Biophys Res Commun (1994 Jun 15) 201(2):748-55

Ginkgo biloba extract EGb 761 was found to be a scavenger of nitric oxide in in vitro acellular systems, under physiological conditions. EGb 761 competed with oxyhemoglobin for reaction with nitric oxide generated during the interaction of hydroxylamine with Complex I of catalase. An EGb 761 dose-dependent decrease in the amount of nitrite formed in the reaction of oxygen with nitric oxide produced from solution of 5 mM sodium nitroprusside was also observed. These data implicate it as a potential therapeutic agent in conditions of altered production of nitric oxide.

Olivier-J; Plath-P

Combined low power laser therapy and extracts of Ginkgo biloba in a blind trial of treatment for tinnitus.

In: Laser Therapy (1993) 5(3): 137-139

Tinnitus is an annoying and often debilitating condition of neurootologic origin but of uncertain aetiology. Many treatment methods have been tried, but to date none has been consistently successful. The present preliminary study presents a blind trial of laser therapy (c/w HeNe 632.8 nm and pulsed GaAs 904 nm) combined with doses of an extract of Ginkgo biloba (50 mg) in two groups of 20 patients, one experimental and one control. All 40 patients received the biloba extract injection, but only the 20 experimental patients received real laser irradiation, 8 days, 8 min per day. The control group received sham irradiation in a blind arrangement. Fifty percent of the experimental group was assessed to have a reduction in tinnitus of more than 10 dB, compared with 5% in the control group in both self-assessment and audiometric findings. Although only a preliminary report, the results are very encouraging, and the authors suggest that this combined photochemotherapy is a promising treatment for tinnitus.

Otani M Chatterjee SS Gabard B Kreutzberg GW

Effect of an extract of Ginkgo biloba on triethyltin-induced cerebral edema.

In: ACTA NEUROPATHOL (BERL) (1986) 69(1-2):54-65

The effect of an extract of Ginkgo biloba was studied on cerebral edema in rats intoxicated with triethyltin chloride (TET). Brains of TET-treated rats showed elevated water and sodium levels and a significant increase in the sodium/potassium ratio. Animals treated with TET plus the extract did not show water and electrolyte changes. The course of intoxication and treatment was studied light- and electron-microscopically. A severe edema with extensive vacuolization was seen in the cerebral and cerebellar white matter. Morphometric measurements revealed a significant decrease in these manifestations of the cytotoxic edema when the animals were treated with an extract of Ginkgo biloba. Thus, we conclude that this extract has a protective effect on the development of a cytotoxic edema in the white matter of the brain.

Oyama Y Fuchs PA Katayama N Noda K

Myricetin and quercetin, the flavonoid constituents of Ginkgo biloba extract, greatly reduce oxidative metabolism in both resting and Ca(2+)-loaded brain neurons.

In: Brain Res (1994 Jan 28) 635(1-2):125-9