Dose Of Ginkgo Biloba Extract Research Articles

Meta-analysis of the efficacy and safety of Ginkgo biloba extract for the treatment of dementia.

BackgroundThe benefit of Ginkgo biloba for the treatment of dementia remains controversial. The aim of this study was to evaluate the efficacy and safety of Ginkgo biloba in patients with dementia in whom administration effects were reported using meta-analysis.MethodsWe searched MEDLINE, Embase, the Cochrane databases, and Ichushi for controlled trials of Ginkgo biloba for the treatment dementia. Clinical characteristics and outcomes were extracted. Meta-analysis results were expressed as standard mean differences (SMDs) in scores of the Syndrome Kurztest (SKT), Alzheimer’s Disease Assessment Scale Cognitive Subscale (ADAS-Cog) for cognition efficacy, or odds ratios (ORs) for dropouts and adverse drug reactions.ResultsThirteen studies using the extract EGb761 met our inclusion criteria, which were duration of 12 to 52 weeks and daily dose of more than 120 mg, and included a total of 2381 patients. Meta-analysis was performed by using 9 of 13 studies, 7 of which used the SKT and 2 ADAS-Cog (dose 120 mg, 26 weeks) scores as efficacy parameters. In meta-analysis of all patients, SMDs (95% confidence interval [CI]) in the change in SKT scores (7 studies) were in favor of Ginkgo biloba over placebo (SMD = –0.90 [–1.46, –0.34]), but 2 studies that used ADAS-Cog did not show a statistically significant difference from placebo for ADAS-Cog (–0.06 [–0.41, 0.30]). For Alzheimer’s disease (AD) and vascular dementia (VaD) subgroups, SMDs [95% CI] in SKT in the combined AD and VaD subgroup (–1.07 [–1.66, –0.47]) and AD subgroup (–1.36 [–2.27, –0.46]) were in favor of Ginkgo biloba over placebo. In terms of daily dose of Ginkgo biloba in the combined AD and VaD subgroup, SMD in SKT score in 240-mg daily dose groups was significantly greater than with placebo (–0.71 [–1.28, –0.14]). Dropout rates for any reason did not differ between two groups, but dropout rates due to side effects were significantly lower in Ginkgo biloba groups compared with placebo groups (OR = 1.72 [1.06, 2.80]).ConclusionsTaking a 240-mg daily dose of Ginkgo biloba extract is effective and safe in the treatment of dementia.

Ginkgo biloba extract for dementia: a systematic review.

BackgroundGiven the increasing burden of dementia internationally and the lack of effective treatments, several countries are already recommending the use of ginkgo biloba extract (GbE) in the treatment of dementia, despite the inconsistent research results about its effectiveness.AimConduct a meta-analysis of studies about the effect of GbE on cognition and daily functioning in persons with dementia.MethodsSearches of various English and Chinese databases identified reports of placebo controlled, randomized trials of ginkgo biloba treatment (lasting a minimum of 22 weeks) for dementia that were published from January 1982 to September 2012. Data extraction and critical appraisal of studies were conducted using the GRADE system. Heterogeneity, sensitivity and potential publication bias of the studies were evaluated using RevMan 5.1. Pooled results of the metaanalysis were presented as forest plots using standardized mean differences (SMD) in scores for continuous variables and relative risk (RR) for categorical variables.ResultsNine studies with a total of 2578 patients met the inclusion and exclusion criteria. Pooled results from the six studies that were included in the meta-analysis (total n=1917) found that GbE was superior to placebo in preventing deterioration in cognitive functioning and in activities of daily living, but these results were only valid for studies with younger subjects (with a mean age below 75). There were no significant differences in the dropout rates between groups or in the overall rates of adverse events during treatment. However, there was considerable heterogeneity in the results between the studies (primarily based on the age of the subjects) and there were several potential biases in the reports (most of which were supported by pharmaceutical firms), so the overall evidence was considered of ‘low quality’.ConclusionThis meta-analysis highlights serious weaknesses in the available studies about this important problem. GbE may be effective in persons under 75 years of age with dementia, but large, placebo controlled, randomized trials focused on milder forms of dementia (including mild cognitive impairment) that compare different doses of GbE and that follow subjects for prolonged periods (at least one year) are needed to confirm this result.

The protective effect of Ginkgo biloba extract against experimental cisplatin ototoxicity: animal research using distortion product otoacoustic emissions

Cisplatin, an effective therapeutic agent for various human cancers, has dose-limiting side effects of ototoxicity and nephrotoxicity. Cisplatin ototoxicity is thought to result from increased amounts of toxic free radicals or cell membrane changes leading to increased intracellular calcium content. Ginkgo biloba extract prevents lipid peroxidation, decreases intracellular free oxygen radical levels, regulates the cell membrane calcium transport mechanism and prevents cell death. This study aimed to investigate the protective effect of Ginkgo biloba extract against cisplatin-induced ototoxicity in rats. Twenty Wistar albino rats with normal hearing (confirmed by distortion product otoacoustic emission testing prior to cisplatin application) were randomly allocated to two groups. Both groups received a single intraperitoneal dose of cisplatin (12 mg/kg). Group two also received daily intraperitoneal doses of Ginkgo biloba extract (100 mg/kg) for 10 days. Distortion product otoacoustic emission measurements were repeated on days 10 and 17 and signal-to-noise ratios were compared. Compared with group one, group two had significantly better distortion product otoacoustic emission results at 3, 4, 6 and 8 kHz on days 10 and 17. These findings suggest that Ginkgo biloba extract protects the inner ear against cisplatin-induced ototoxicity.

Long-term use of standardised ginkgo biloba extract for the prevention of Alzheimer's disease (GuidAge): a randomised placebo-controlled trial

Prevention strategies are urgently needed to tackle the growing burden of Alzheimer's disease. We aimed to assess efficacy of long-term use of standardised ginkgo biloba extract for the reduction of incidence of Alzheimer's disease in elderly adults with memory complaints. In the randomised, parallel-group, double-blind, placebo-controlled GuidAge clinical trial, we enrolled adults aged 70 years or older who spontaneously reported memory complaints to their primary-care physician in France. We randomly allocated participants in a 1:1 ratio according to a computer-generated sequence to a twice per day dose of 120 mg standardised ginkgo biloba extract (EGb761) or matched placebo. Participants and study investigators and personnel were masked to study group assignment. Participants were followed-up for 5 years by primary-care physicians and in expert memory centres. The primary outcome was conversion to probable Alzheimer's disease in participants who received at least one dose of study drug or placebo, compared by use of the log-rank test. This study is registered with ClinicalTrials.gov, number NCT00276510. Between March, 2002, and November, 2004, we enrolled and randomly allocated 2854 participants, of whom 1406 received at least one dose of ginkgo biloba extract and 1414 received at least one dose of placebo. By 5 years, 61 participants in the ginkgo group had been diagnosed with probable Alzheimer's disease (1·2 cases per 100 person-years) compared with 73 participants in the placebo group (1·4 cases per 100 person-years; hazard ratio [HR] 0·84, 95% CI 0·60-1·18; p=0·306), but the risk was not proportional over time. Incidence of adverse events was much the same between groups. 76 participants in the ginkgo group died compared with 82 participants in the placebo group (0·94, 0·69-1·28; p=0·68). 65 participants in the ginkgo group had a stroke compared with 60 participants in the placebo group (risk ratio 1·12, 95% CI 0·77-1·63; p=0·57). Incidence of other haemorrhagic or cardiovascular events also did not differ between groups. Long-term use of standardised ginkgo biloba extract in this trial did not reduce the risk of progression to Alzheimer's disease compared with placebo. Ipsen.

Testicular Histomorphometry and Ultrastructure of Rats Treated with Cadmium and Ginkgo biloba

The aim of this study is to investigate the association of a single low dose of Cd and daily doses of Ginkgo biloba extract (GbE) on the testis and accessory glands of rats. The animals were treated with a single dose of 3 µmol/kg body weight of cadmium chloride (CdCl₂) and/or 100 mg/kg body weight of GbE. The plasma testosterone levels; corporal, testicular, and accessory glands weight; gonadosomatic index, volumetric proportion; and absolute volume of testicular components did not change after the treatments. CdCl₂ caused significant reduction in Leydig cells volume and altered Leydig cell morphology, as well as vacuolated Sertoli cells cytoplasm, irregular chromatin condensation of late spermatids, and modified acrosome formation. However, animals that received GbE did not show these alterations. The reversal of Cd-induced alterations by the extract is a strong indication that G. biloba is helpful in diminishing the effect of Cd toxicity.

Influence of Ginkgo biloba extract on the pharmacodynamic effects and pharmacokinetic properties of ticlopidine: An open-label, randomized, two-period, two-treatment, two-sequence, single-dose crossover study in healthy Korean male volunteers

Background: Ginkgo biloba extract is an herbal medicine used in the treatment of vascular disorders that may be coadministered with antiplatelet agents such as ticlopidine. Regulatory authorities requested evaluation of the pharmacodynamic and pharmacokinetic interactions between these entities, according to the drug-development guidance for fixed-dose combination formulations in Korea. Objective: This study was performed to evaluate the potential pharmacodynamic and pharmacokinetic interactions between ticlopidine and Ginkgo biloba extract. Methods: An open-label, randomized, 2-period, 2-treatment, 2-sequence, single-dose crossover study was conducted in healthy Korean male volunteers. All volunteers were randomly assigned to a sequence group for the 2 treatments, which consisted of ticlopidine 250 mg alone and ticlopidine 250 mg with Ginkgo biloba extract 80 mg, separated by a 1-week washout period between the treatments. Bleeding time was determined just before dosing and at 5, 12, and 48 hours after dosing. Platelet aggregation was evaluated before dosing and at 4, 8, 26, and 48 hours after dosing. Blood samples (8 mL) from each of the volunteers were collected from an indwelling intravenous cannula inserted into a forearm vein before dosing and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 24, and 48 hours after dosing. Ticlopidine concentrations were determined by a validated method using HPLC and ultraviolet detection. Adverse events were identified using general health-related questions, vital signs, physical examinations, ECGs, and laboratory tests. Results: A total of 24 healthy men participated in the study (mean [SD] age, 24.1 [4.3] years; weight, 66.6 [7.4] kg; height, 174.7 [5.0] cm). The baselinecorrected bleeding times were not significantly different between the ticlopidine-alone and ticlopidine/ Ginkgo biloba groups, and changes in platelet aggregation were not significantly different between the groups. Likewise, the pharmacokinetic parameters of ticlopidine were not significantly different between the groups; the geometric mean ratios of the ticlopidine/ Ginkgo biloba group to the ticlopidine-alone group were 1.03 (90% CI, 0.92–1.16) for C max, 1.08 (90% CI, 0.98–1.19) for AUC 0-last, and 1.10 (90% CI, 1.00–1.20) for AUC 0–∞. A total of 28 adverse events were reported: 11 in the ticlopidine-alone group and 17 in the ticlopidine/ Ginkgo biloba group. The adverse events judged to be possibly related to ticlopidine in the ticlopidine-alone group were epigastric discomfort (2 cases), diarrhea (1), skin eruption (1), and a feeling of being cold (1) or hot (1). The adverse events judged to be related to ticlopidine or Ginkgo biloba in the ticlopidine/ Ginkgo biloba group were epigastric discomfort (2), diarrhea (2), nausea (2), and headache (1). Conclusions: In this small group of healthy Korean men, the addition of a single dose of Ginkgo biloba extract did not prolong the bleeding time and was not associated with additional antiplatelet effects compared with the administration of ticlopidine alone. The coadministration of Ginkgo biloba extract with ticlopidine was not associated with any significant changes in the pharmacokinetic profile of ticlopidine compared with ticlopidine administered alone.

A Randomized, Double-Blind, Placebo-Controlled Trial of Two Doses of Ginkgo Biloba Extract in Dementia of the Alzheimers Type

Previous studies of Ginkgo biloba extract (GbE) in patients with various forms of cognitive impairment or dementia have shown promising results. To determine the clinical efficacy of GbE in mild to moderate dementia of the Alzheimer type. Randomized, placebo-controlled, double-blind, parallel-group, multicenter trial. Outpatient clinics of universities and private research centers specialized in dementia. 513 outpatients with uncomplicated dementia of the Alzheimer's type scoring 10 to 24 on the Mini-Mental State Examination and less than 4 on the modified Hachinski Ischemic Score, free of other serious illnesses and not requiring continuous treatment with any psychoactive drug. 26-week treatment with GbE at daily doses of 120 mg or 240 mg or placebo. Cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog), Alzheimer's Disease Cooperative Study Clinical Global Impression of Change (ADCS-CGIC). There were no significant between-group differences for the whole sample. There was little cognitive and functional decline of the placebo-treated patients, however. For a subgroup of patients with neuropsychiatric symptoms there was a greater decline of placebo-treated patients and significantly better cognitive performance and global assessment scores for the patients on GbE. The trial did not show efficacy of GbE, however, the lack of decline of the placebo patients may have compromised the sensitivity of the trial to detect a treatment effect. Thus, the study remains inconclusive with respect to the efficacy of GbE.

The effects of acute doses of standardized Ginkgo biloba extract on memory and psychomotor performance in volunteers

This study investigated the effects of acute doses of Ginkgo biloba extract (GBE) on memory and psychomotor performance in a randomized, double-blind and placebo controlled 5-way cross-over design. Thirty-one volunteers aged 30–59 years received GBE 150 mg (50 mg t.d.s), GBE 300 mg (100 mg t.d.s.), GBE 120 mg mane and GBE 240 mg mane and placebo for 2 days. Following baseline measures, the medication was administered at 0900 h for the single doses and at 0900, 1500 and 2100 h for the multiple doses. The psychometric test battery was administered pre-dose (0830 h) and then at frequent intervals until 11 h post dose. The results confirm that the effects of GBE extract on aspects of cognition in asymptomatic volunteers are more pronounced for memory, particularly working memory. They also show that these effects may be dose dependent though not in a linear dose related manner, and that GBE 120 mg produces the most evident effects of the doses examined. Additionally, the results suggest that the cognitive enhancing effects of GBE are more likely to be apparent in individuals aged 50–59 years. Copyright © 1999 John Wiley & Sons, Ltd.

Cardioprotective and Anti-oxidant Effects of the Terpenoid Constituents ofGinkgo bilobaExtract (EGb 761)

Hemodynamic and electron spin resonance analyses were used to assess thein vivoandin vitrocardioprotective and antioxidant effects of therapeutically relevant doses ofGinkgo bilobaextract (EGb 761) and its terpenoid constituents (ginkgolides A and B, bilobalide) in the rat. Significant anti-ischemic effects, indicating improved myocardial functional recovery, were observed after repeated (15-day) oral treatments with both EGb 761 (60 mg/kg/day) and ginkgolide A (4 mg/kg/day), as compared to placebo.In vitropre- and post-ischemic perfusion of hearts in the presence of the ginkgolides A and B (both at 0.05μg/ml) or bilobalide (0.15μg/ml), but not EGb 761 (5μg/ml), significantly improved all hemodynamic parameters. Post-ischemic levels of the 5,5-dimethyl-1-pyrrolineN-oxide (DMPO)/hydroxyl radical spin-adduct (DMPO-OH) in coronary effluents were significantly decreased afterin vivooral treatments or afterin vitroperfusion with EGb 761 or the terpenes, the most effective compound being ginkgolide A. As the presence of the terpenes did not influence the formation of the superoxide/DMPO adduct or DMPO-OH in acellular tests with superoxide and hydroxyl radical generators, their cardioprotective effects appear to involve an inhibition of free radical formation rather than direct free radical scavenging.