Clinical Studies
Cardiovascular and Circulatory Disorders
Overall, studies confirm the efficacy of Ginkgo extract for treating disturbances of cerebral (or cerebrovascular) function, especially in elderly patients. Well-designed studies have indicated therapeutic efficacy for conditions of mild to moderate forms of degenerative dementia. Larger studies are required for EEG analysis and the examination of saccades (rapid involuntary eye movements). Thus far, studies indicate treatment with Ginkgo extract EGb 761 increases alertness or vigilance (DeFeudis, 1991).
Kleijnen and Knipschild (1992a) examined 40 clinical studies on Ginkgo in the treatment of cerebral insufficiency published from 1977-1991. Of these, only 8 were judged to be well-performed, including 4 not cited by SØholm (1998) above: Wesnes et al., 1987; Haguenauer et al., 1986; Meyer, 1986; Taillandier et al., 1986. And yet all these trials lacked checking for blindness of the placebo (inquiring of the patients as to whether they thought they had received the active or placebo medication) (Kleijnen and Knipschild, 1992a).
SØholm (1998) reviewed the clinical literature from 1975-1997 when around 2,500 patients had participated in over 40 controlled trials of Ginkgo. SØholm noted that from placebo-controlled studies in about 1,200 patients, cognitive symptoms were reduced by approximately 25% overall. Eleven of the clinical studies fulfilled the essential criteria for biometric parameter analysis used in testing clinical drugs: Le Bars et al., 1997; Kanowski et al., 1996; Vesper and Hänsgen, 1994; Grässel, 1992; Brüchert et al., 1991; Halama, 1991; Hofferberth, 1991; Maier-Hauff, 1991; Schmidt et al., 1991; Eckmann, 1990; Vorberg et al., 1989. Hopfenmüller (1994) conducted a meta-analysis of clinical trials on Ginkgo in the treatment of cerebral insufficiency and found 7 that confirmed Ginkgo extract was effective compared to placebo. Efficacy in treating both individual symptoms and the total complex of symptoms was calculated as significant compared to placebo (p<0.01).
In reviewing the value of Ginkgo as a substance to reduce declining mental function, Curtis-Prior et al. (1999) found the activities of Ginkgo as a cerebral blood flow-enhancing, antioxidant, and free radical scavenging substance to be well-documented. Combined with the activity of antagonizing the pro-inflammatory platelet aggregating factor, as shown by Guinot et al. (1989) in healthy male volunteers, they assessed these activities as "compatible" with the benefits seen in clinical reports of Ginkgo in treatments of dementia and cerebral insufficiency. At the same time, they lamented the over-reliance on self-assessment questionnaires in clinical trials of the extract to assess efficacy and suggested that for future, more objective assessments, the already tested and computerized Cambridge Neuropsychological Test Automated Battery (CANTAB) be employed.
Vesper and Hänsgen (1994) conducted a double-blind, placebo-controlled study in which they administered placebo or a Ginkgo extract (LI 1370) for over 12 weeks to 90 outpatients (average age 62.7 years) diagnosed with cerebral insufficiency. In comparison to placebo, significant improvement in patient performance was noticed in various parameters at the end of the treatment. The parameters measured included: a) the quality of information processing stabilized in time-interval testing; b) ability to attain consistent attentiveness over a long period of time while performing certain tasks, and ability to perform tasks which required the patient to quickly reorient and readapt; c) improvement in visual memory with respect to parameters sensitive to cerebral insufficiency; d) positive changes in subjective performance as tracked by the patient or by the people in the patient’s environment.
In a year long open study of 112 patients with chronic cerebral insufficiency, each of whom received 120 mg/day of Ginkgo extract, regression of major symptoms of vertigo, headache, tinnitus, short-term memory loss, vigilance, and mood disturbances were found. Heart rate, blood pressure, and cholesterol and triglyceride levels showed no change during the course of the study, nor were any significant side effects or drug interactions noted at any time (Vorberg, 1985).
The second main therapeutic area of Ginkgo extract, which is attended by confirming clinical studies, is that of peripheral vascular disturbances such as intermittent claudication. Most trials in this area have been performed on patients suffering from arterial occlusive diseases characterized as Stage IIb, according to Fontaine. Assessment of the overall value of Ginkgo extract for this therapeutic category is difficult, as is usual in assessing drugs for chronic arteriopathies, because of the inherent inter-individual variations in these diseases (DeFeudis, 1991).
Peters et al. (1998) investigated the effects of Ginkgo extract (EGb 761, 40 mg 3 X daily for 24 weeks) in 111 adult patients diagnosed with peripheral occlusive arterial disease (POAD) of the legs at stage IIb intermittent claudication (pain-free walking distance on a treadmill of less than 150 m). The study was a multicenter, randomized, placebo-controlled, double-blind trial. Treatment with the extract or placebo began after a two-week placebo run-in phase. The goal of the study was to detect a difference in the pain-free walking distance after treatment with the Ginkgo extract, which was measured after weeks 8, 16 and 24 on a treadmill. Throughout the treatment period, the Ginkgo group showed a more obvious and continuous increase in the mean pain-free walking distance until at the end, the increase was 44.7 m compared to baseline after the two-week placebo run-in (108.5 m), versus a mean increase of 21.4 m in the placebo group. The difference was statistically significant at all 3 examination times in the Ginkgo group (p=0.017, p=0.007, and p=0.016 at week 24) compared to the placebo group. The mean maximum pain-free walking distances which were also significantly higher in the Ginkgo group versus the placebo group at weeks 8, 16 and 24: +21.8 versus +10 m; +35.0 versus 19.3 m, and +61.1 compared to 25.0 m. Remarkably, the only side effects reported in any the participants were gastric pain; heartburn was reported in one patient in the placebo group. Accordingly, the Peters and coworkers concluded that their proves the Ginkgo extract can significantly increase pain-free walking distances in these patients under the standardized measurements they employed, that the treatment is clinically relevant and well-tolerated, and similar in efficacy to pentoxifylline in the treatment of POAD.
Mouren et al. (1994) conducted a randomized, placebo-controlled, double-blind, parallel study involving 20 patients diagnosed with claudicating atherosclerotic arterial occlusive disease of stage II. All patients were given placebo for 15 days under single-blind conditions, and then randomized into two groups receiving either placebo or Ginkgo extract EGb 761 (320 mg/day). Transcutaneous oximetery (measuring the partial pressure of oxygen during exercise) was used to estimate local arterial perfusion and regional capillary perfusion. After 4 days of Ginkgo extract, the areas of ischemia decreased by 38%, whereas in the placebo group they remained relatively unchanged. The difference was statistically significant.
Thomson et al. (1990) followed 37 patients with stage II peripheral vascular disease in a randomized, double-blind, placebo-controlled study. After an initial washout period, the patients received either placebo or a Ginkgo extract (Tanakan®) for 6 months. At 6, 12, and 24 weeks and before the beginning of treatment, effects were measured by claudication distance, A/B ratio, and Doppler ankle pressure response to exercise, together with recovery time and a 10 cm analog scale (LAS) estimation of maximal pain severity. LAS scores were significantly improved in the Ginkgo group after 24 weeks, and claudication distance was significantly increased compared to placebo. However, A/B ratio, Doppler ankle responses to exercise for any interval and the post-exercise recovery time all failed to show any significant change in either group. The authors concluded that Ginkgo extract was effective in improving claudication distance and pain associated with walking, although the Doppler studies failed to suggest gross improvement in perfusion of the leg in peripheral vascular disease.
Bauer (1984) followed 79 patients suffering from peripheral arteriopathy who were given placebo or Ginkgo extract (Rokan®, 40 mg/day) for 6 months in a double-blind, randomized clinical trial. Measurements of pain-free walking distance, maximum walking distance, and plesthymography recordings indicated Ginkgo extract to be significantly superior to placebo. These results confirmed patient and physician overall assessments of the treatment.
Thrombosis, hemostasis, and embolism
Citing the presence of PAF in the mucosa of patients with active ulcerative colitis, Sandberg-Gertzén (1993) conducted a small open study using a standardized extract of Ginkgo (Cedemin) in 10 patients with the disease. The two men and 8 women participants (ages 35-75) suffered from light to moderate symptoms yet showed light to severe pathological states upon sigmoidoscopic examination. Every evening for 3 weeks, the patients received the extract in the form of an enema in a dosage of 200 mg/100 mL of suspension. Two patients found some effect, 5 experienced no benefit, and in two the disease went into remission. But since these results were no better than those on placebo, Sandberg-Gertzén concluded that the Ginkgo extract delivered as an enema appears to be ineffective against distal ulcerative colitis (Sandberg-Gertzén, 1993).
Chung et al. (1987) examined the effect of a ginkgolide mixture (BN 52063) containing 40% ginkgolide A, 40% ginkgolide B, and 20% ginkgolide C on PAF in 6 normal human subjects in a double-blind, placebo-controlled, crossover study. The conclusion drawn from this study was that the ginkgolide mixture exhibited PAF inhibition due to several measurements. Two hours. after ingestion of 400 mg of the mixture, weal and flare responses were inhibited in a dose-related manner. From 120 mg, the flare area was reduced by a mean of 62.4%, and the weal volume by a mean of 60%. Either dose inhibited PAF-induced platelet aggregation in platelet-rich plasma. The same mixture was also found to inhibit PAF-induced, but not ADP-induced, platelet aggregation.
Metabolic and Nutritional Disorders
In a prospective trial, Pietta et al. (1998) compared the total radical-trapping antioxidant potential (TRAP) of a Ginkgo extract (100 mg ginkgolides and 400 mg Ginkgo flavonoids) to that of an extract of green tea (400 mg total catechin tannins). The placebo-controlled study was conducted with 12 healthy subjects ages 20-25, none of whom were taking antioxidants and had a habitually low dietary flavonoid intake. Following a fast, the subjects ingested either a placebo (maltodextrin), Ginkgo extract (~1.6 g), or green tea extract (600 mg). Tests of blood samples taken before the substances and at 6 hour intervals revealed a longer lasting and more rapid antioxidant potential of the Ginkgo extract compared to the green tea extract. Yet, in a separate assay of the total antioxidant potential of these extracts, green tea showed about twice the activity of the Ginkgo extract (5.2 mM Trolox versus 2.4 mM Trolox value). Pietta et al. concluded, therefore, that in order to be useful, in vitro comparisons of the antioxidant activity of medicinal plants must be combined with in vivo comparisons.
Performance and endurance enhancement
Roncin et al. (1996) tested the prophylactic potential of Ginkgo extract (EGb 761, 80 mg 2 x/day for 30 days, dispensed daily) in a placebo-controlled, randomized study on altitude sickness in 44 healthy, male mountain climbers (ages 28-31) during an ascent in the Himalayas (1800 to 5200 m). The researchers pointed out that earlier investigators had found favorable results in related trials of the extract on preventing mountain sickness (a.k.a., high altitude sickness) (Ajasse, 1984), and on microcirculation of the extremities during exposure to cold (Clement et al., 1982). Inclusion criteria included a score of 2 or greater on the acute mountain sickness questionnaire in order to diagnose the illness; scores from which show a good correlation with the Environmental Symptom Questionnaire. Exclusion criteria included the long-term use of various prescription drugs that would interfere with the results (e.g., anticoagulants, calcium channel blockers, anti-ischemic agents) and rheological treatments. For pain, the subjects were asked to refrain from using aspirin. In addition to the questionnaires, peripheral vasomotor reactions were measured by plethysmography at room temperature and functional disability was measured on a 6-point scale for numbness, swelling of hands, pain, stiffness, and parasthesia. The active treatment group included 3 exsmokers and 2 smokers. Despite this unfavorable weighting of the Ginkgo group compared to the placebo group, the results still showed a highly significant protection from symptoms of altitude sickness in the Ginkgo group compared to the placebo group, and none of the patients failed to complete the trial. In the placebo group, 40.9% developed acute altitude sickness on the basis of cerebral factor versus no one in the Ginkgo group. On the basis of respiratory factor, 13.6% developed acute altitude sickness versus 18.8% on placebo. The effect of cold showed a most noticeable difference with the placebo group deteriorating by 104% and the Ginkgo group improving by 22.8% (p<10-6). Similar, highly significant results were found in favor of Ginkgo over placebo by physician assessment, the acute mountain sickness questionnaire, and a vasomotor questionnaire. The decrease in vasomotor disorders affecting the extremities as measured by plethysmography was also highly significant (p<10-8) in the Ginkgo group (Roncin et al., 1996).
Neurological, Psychological, and
Behavioral Disorders
Alzheimer’s disease
Oken et al. (1998), published a meta-analysis of clinical trials of Ginkgo extract in the treatment of cognitive function in Alzheimer’s disease. The investigators found only 4 out of 50 that met all 6 of the essential inclusion criteria used (Le Bars et al., 1997; Kanowski et al., 1996; Hofferberth, 1991; Wesnes et al., 1987). This amounted to 212 subjects in the placebo groups and the same number in the Ginkgo groups. Their quantitative analysis showed a significant (p<0.0001) although modest effect size of the Ginkgo treatment (at 120-240 mg/day for 3-6 months) when including the Alzheimer Disease Assessment Scale-cognitive subtest. They concluded that more research is needed to determine what functional improvements may result, the most effective dosage to use, and the active constituents of Ginkgo extract in the treatment of cognitive impairment or dementia in Alzheimer’s disease.
Maurer et al. (1998) used an extract of Ginkgo (EGb 761, 240 mg/day for 3 months) in a double-blind, randomized, placebo-controlled parallel-group design trial in 20 patients diagnosed with mild to moderate dementia of the Alzheimer type (DAT). The placebo group showed deterioration while the Ginkgo group showed a modest though significant improvement (p<0.013). In the ADAS cognitive subscale, a psychometric test, the level of improvement was comparable to that of a cholinesterase inhibitor administered for the same length of time in another study. In addition, EEG and Clinical Global Impression tests showed indications of improvement in dynamic functional and psychopathological states in the Ginkgo group. Maurer et al. noted that the improvements in attention and memory in mild to moderate DAT were evidenced in the topographic normalization of EEG recordings after the 3-month treatment with Ginkgo, but that this requires further confirmation. No adverse effects were reported and their data were in agreement with a meta-analysis on EGb 761 performed independently by Weiß and Kallischnigg (1991).
Le Bars et al. (1997) conducted a placebo-controlled, double-blind, randomized study of Ginkgo extract EGb 761 on 202 patients to assess the efficacy and safety of EGb 761 in Alzheimer’s disease or multi-infarct dementia, without other significant medical conditions. The primary outcome measures were Alzheimer’s Disease Assessment Scale-Cognitive subscale (ADAS-Cog), Geriatric Evaluation by Relative’s Rating Instrument (GERRI), and Clinical Global Impression of Change (CGIC). In 27% of the patients taking EGb 761, an improvement of at least 4 points was seen for the ADAS-Cog compared to placebo. For GERRI, 37% taking EGb 761 were considered improved compared to 23% taking placebo, although no differences were seen for placebo in CGIC. In addition, no significant differences were seen compared to placebo regarding the safety profile of EGb 761.
Cognitive disorders
Winther et al. (1998) studied the effect of a Ginkgo extract (GB-8) in elderly volunteers diagnosed with well-defined, mild to moderate age-related cognitive impairment in accordance with the Mini-Mental State Examination (M-MSE). Volunteer selection was limited to those showing a score of 22-28 in the M-MSE. In addition, they measured changes in blood pressure before and after the treatment period. The randomized double-blind, placebo-controlled study consisted of 54 patients (61-88 years old) who were assigned to either a placebo group, a low dosage group (40 mg 3 X/day for 3 months), or a high dosage group (80 mg 3 X/day for 3 months). After the first 4 weeks and the end of the treatment period, results of the Wechsler Memory Scale test showed a significant improvement (p<0.016) in the low dosage group and tendency to improvement in the high dosage group compared to the placebo group, which showed no significant change. Results from the Memory Assessment Clinic Self-Rating Scale (MAC-S) at the start and after the end of the study revealed significant changes compared to baseline in the low dosage group and the high dosage group. Changes in the placebo group were less significant. Comparing the 3 groups using the cerebral insufficiency test, Winther et al. reported that compared to baseline the low dosage group improved the most and that the improvement was highly significant (p<0.001). As for blood pressure, a significant decrease (p<0.04) was found only in diastolic pressure (73 to 68 mm Hg) and only in the low dosage group. The researchers concluded that in a homogenous group of elderly subjects with mild to moderate cognitive impairment (primarily due to the aging process), the low dosage of Ginkgo extract (GB-8) improved short-term verbal memory, attention, and concentration within the first 4 weeks of treatment. The effect did not become significant, however, until the end of 3 months of treatment. They added that some patients in the high dosage group experienced side effects (sleep disturbances, dyspepsia, and dizziness). With respect to the change in diastolic BP, the authors note that this effect might support the suggestion by others (Subhan and Hindmarch, 1984), that Ginkgo improves cognitive function through a vasodilating activity. Winther et al. add that since the effect was clinically relevant, it warrants further study in hypertensive patients.
Brautigam et al. (1998) studied the potential cognitive benefits of a water/alcohol extract (70% v/v) of Ginkgo leaves (Geriaforce®, Biohorma B.V., 1:4 extract; 0.34 mg/mL total ginkgolides and 0.20 mg/mL total flavone glycosides). The 24-week randomized, double-blind, placebo-controlled study involved 241 non-institutionalized elderly patients (both sexes, ages 55-86) with self-reported concentration/memory complaints. Results were compared between a placebo group, a low-dose (40 drops or 1.9 mL 1:1 with placebo 3 X/day), and a high-dose Ginkgo group (40 undiluted drops, or 1.9 mL 3 X/day). Visual short-term memory (Benton test) appeared to have improved significantly (p=0.0076). The low-dose group showed an optimal increase of 26%, while increases of 18% and 11% in the high-dose and placebo groups, respectively, were found. However, no improvements were found compared to placebo in the Ginkgo groups in verbal short-term memory or verbal long-term memory. In a subgroup of patients who showed comparatively lower baseline scores at the start of the trial, Brautigam et al. found a significant though modest difference compared to placebo (p<0.02) in long-term memory: recognition improvement using (Rey 2 test). The authors concluded that while Ginkgo extracts "might be promising" in cognitively-impaired elderly persons, further research with longer trials in patients with lower cognitive function using tests for sensomotoric and cognitive speed and accuracy are recommended.
Rai et al. (1991) conducted a 6-month, double-blind, placebo- controlled study of Ginkgo extract (Tanakan®, 40 mg, 3 X/day) in 31 patients over the age of 50 who showed a mild to moderate degree of memory impairment. Digit copying sub-test of the Kendrick battery performance improved at both 12 and 24 weeks, and the median speed of response on a computerized version of a classification task showed significant improvement over placebo after 24 weeks The researchers concluded that Ginkgo extract exhibited a beneficial effect on cognitive function in this group of patients.
Dementias
Kanowski et al. (1996) administered Ginkgo extract (EGb 761, single dose 240 mg/day p.o. for 6 months) or placebo to 216 outpatients (ages >55) diagnosed with mild (79%) or moderate (21%) multi-infarct dementia and primary dementia (senile or presenile primary degenerative, Alzheimer type), according to the DSM-III-R. Of the 156 who completed the prospective randomized, double-blind, placebo-controlled trial, there was a significantly greater number who showed improved responses in the Ginkgo group (p<0.05 in both the Clinical Global Impressions item two and Syndrom-Kurztest scores). An intent to treat analysis in 205 of the patients showed similar results. Also, the number of responders was significantly greater compared to the placebo group (p<0.005). Among adverse events, 63 occurred in the Ginkgo group with 5 serious events, versus 59 in the placebo group with two serious events. While all serious adverse events could not be attributed to EGb 761, a number of possible reactions could not be ruled out: headache, allergic skin reactions, and gastrointestinal complaints in 4 cases; the latter being more intense in 9 patients in the placebo group (Kanowski et al., 1996
Weitbrecht and Jansen (1985) in a double-blind, randomized trial compared a 3-month treatment with Ginkgo biloba extract versus placebo in a homogeneous population of 40 geriatric patients with primary degenerative dementia. The treatment was evaluated by patient self-evaluation, clinical geriatric scales, and psychomotor tests, which were carried out before the study and after 4, 8, and 12 weeks of treatment. By the 8th week, statistically significant improvements were found in the Ginkgo group by psychometric tests and clinical scales.
Gebner et al. (1985) studied the effect of daily administration of Ginkgo extract (3 X 40 mg) compared to placebo and 5 mg nicergoline in 60 patients with mental deterioration, which corresponded with an increase in age. The subjects were assessed with a series of examinations and pharmaco-EEG before and at 4, 8, and 12 weeks The EEG results revealed no advantage of Ginkgo extract over the two reference drugs, but the vigilance of those who had a more unfavorable initial situation improved. The authors concluded that Ginkgo extract has a positive effect on geriatric subjects diagnosed with deterioration of mental performance and vigilance as reflected at the behavioral level. By contrast, very little improvement was noted in healthy subjects.
Retinopathies
Chung et al. (1999) found ocular blood flow velocity significantly increased by Ginkgo extract (Ginkoba®, 40 mg p.o. 3 X/day X 2) in a randomized prospective double-blind cross-over phase I clinical trial in 11 healthy volunteers (mean age 34). Ocular blood flow velocity was measured by color Doppler imaging and none of the patients had any history of either ocular or systemic disease or were taking systemic or topical medications concomitantly with the trial. The ophthalmic artery showed a significant increase in end diastolic velocity versus baseline compared to placebo, without altering arterial blood pressure, the heart rate, or intraocular pressure. No discomfort or side effects from the treatment were found. Chung et al. noted that despite increasing evidence that patients with glaucoma are burdened with poor ocular blood flow, current treatments neither document this fact nor offer treatments for the problem. Yet, considerable research of late has focused upon optimum ocular circulation. The authors further note that vascular abnormalities, such as deficits in ocular blood flow and altered vasodilation of choroidal circulation in glaucoma patients, may be some of the first signs of the disease.
Psychological and behavioral disorders
Depression
Schubert and Halama (1993) investigated the effect of EGb 761 (80 mg X 3/day for 8 weeks) in 40 patients (ages 51-78) suffering from episodes of depression combined with mild to moderate cerebral dysfunction. For a minimum of 3 months, the patients showed a lack of response to treatment with tetracyclic and tricyclic antidepressants (e.g., amitriptyline, doxepin, maprotiline, trimipramine). Maintaining their antidepressant medications, half the patients received the Ginkgo extract while the other half received placebo. The randomized placebo-controlled, double-blind study found highly significant results at 4 weeks into the study, with the Hamilton Depression Scale (HAMD) decreasing from 14 to 7. Results were still significant after 8 weeks (p<0.01) and cognitive functions also showed significant improvement in the Ginkgo group.
Seasonal Affective Disorder (SAD)
In 17 patients (ages 26-68 years) diagnosed with seasonal affective disorder (SAD), Lingaerde et al. (1999) conducted a randomized double-blind, placebo-controlled, parallel group study of Ginkgo extract PN246 (Bio-Biloba, Pharma Nord, Vejle, Denmark, 120-160 mg/day) as a possible means of preventing winter depression. The extract used was standardized to contain 7 mg terpene lactones and 24 mg flavone glycosides per coated tablet. After the 10-week trial (extended to a period of two years), Lingaerde et al. reported no significant difference compared to placebo.
Sikora et al. (1998) studied the effect of Ginkgo (EGb 761, 240 mg/day, p.o.) in 32 men diagnosed with erectile dysfunction suspected to be of vasculogenic origin. The 24-week trial placebo-controlled, double-blind, randomized trial included diagnostic measurements included nocturnal penile tumescence and rigidity recording (NPTR), duplex-sonography, dynamic cavernosometry, and examinations of drug-induced tumescence, before and after the treatment period. The drop-out rate (reasons not stated) was relatively high, leaving just 23 patients for follow-up examination. Overall, the results showed no significant benefit from the Ginkgo extract in these patients, which was in contrast to earlier results from an uncontrolled preliminary study.
Tamborini and Taurelle (1993) conducted a double-blind, placebo-controlled multicenter trial of Ginkgo (EGb 761, 80 mg twice daily) in 165 women between the ages of 18 and 45 who experienced congestive symptoms of PMS. These symptoms were present in all the patients during 7 days of the cycle and consisted of edema of the extremities, pain in the breast, and abdomino-pelvic distention accompanied by neuropsychological problems. Treatment with the Ginkgo extract or placebo was received by the patients for two menstrual cycles after an observational cycle, and initiated from day 16 of the first until day 5 of the second cycle. Patient self-evaluations during the treatment phase and evaluations by practitioners before the treatment and after were used to judge the efficacy of the Ginkgo extract. Of the 143 patients who completed the trial, a significant difference was found in the Ginkgo group versus the placebo group in the amelioration of congestive symptoms (p<0.07), which was especially noticeable in those affecting the breast (p<0.03), as well as edema of the extremities (p<0.05). Significant improvements were also seen in neuropsychological symptoms (irritability-aggression) compared to placebo (p<0.001) and the tolerability of the treatment was judged to be good or very good by 86% of the patients. Patient evaluation scores were significantly higher in favor of the Ginkgo extract versus placebo (p<0.07) and in the evaluation of the practitioners (p<0.01).
Respiratory and Pulmonary Disorders
Ten patients with exercise-induced asthma were studied (Wilkens et al., 1990) for the effect of single-dose and short-term treatment with the PAF-antagonist BN 52063, which is a mixture of ginkgolides A, B and C (molar ratio 2:2:1). Inhalation of BN 52063 was not found to have beneficial effects on pulmonary function, but short-term treatment by mouth appeared to provide partial protection against exercise-induced bronchoconstriction and antagonized platelet secretion of Beta-TG and PF4. The authors noted that further studies were warranted to more decisively evaluate the role of this mixture in asthma therapy.