Ginkgo is popularly known as living fossils. It is also known by other names like Fossil tree, Kew Tree and Silver Apricot. Ginkgo trees are in a position to live long for thousands of years. Historically, medicinal use of Ginkgo was documented in 2600 BC for the treatment of respiratory tract diseases like bronchitis and bronchial-asthma. The botanical name of ginkgo is Ginkgo biloba Linn. and it is a member of family Ginkgoaceae. Ginkgo although not described in Ayurvedic Pharmacopeia is major herbal drug of western Medical Herbalism.
Ginkgo biloba is found in a wild state in China only. Now it is cultivated across the globe. The leaves of Ginkgo are used to prepare standardized extracts. Chemically it contains flavonoids (isorhamnetin, kaempferol), bioflavonoids (5-methoxybilobetin, amentoflavone, bilobetin, ginkgetin, isoginkgetin, sciadopitysin), diterpenes: ginkgolide A, B, C, J, M.
- Cerebral insufficiency.
- Difficulty concentrating.
- Hearing disorders.
- Leg-pain when walking (claudication).
- Memory disorders, including Alzheimer’s disease..
- Memory loss.
- Mood disturbances.
- Raynaud’s syndrome.
Preclinical Studies of Ginkgo Biloba
Anti-anxiety, anti-inflammatory anti-lipoperoxidant, antioxidant, anticancer, anti-platelet, aphrodisiac, anti-stress, anti-ischemic, antidepressant, and gastro protective.
Clinical Studies of Ginkgo Biloba:
- In a randomized, double-blind, placebo-controlled trial two doses of Ginkgo biloba extract were tested in five hundred thirteen patients with dementia of the Alzheimer’s type. The patients were instructed to consume Ginkgo biloba extract at daily doses of 120 mg or 240 mg or placebo for 26-weeks. The trial, however reported ineffectiveness of Ginkgo biloba extract in dementia of the Alzheimer’s type.
- The U.S. trial enrolled more than 300 people with Alzheimer’s disease or non-Alzheimer’s dementia. The participants were instructed to consume either 40 mg of extract of Ginkgo biloba or placebo by oral-route, three times a day. The results showed significant (but not dramatic) improvements in the treated group.
- In a randomized, placebo-controlled trial with Ginkgo biloba (180 mg per day) significant cognitive benefits were observed in healthy persons.
- A randomized, placebo-controlled trial with Ginkgo biloba failed to show efficacy in memory loss.
- In a double-blind cross-over trial, sixty minutes after internal administration of a single dose (600 mg dose of extract of Ginkgo biloba), there was significant improvement in short-term memory parameters as compared to the control. According to researchers, the study demonstrates a specific activity of extract of Ginkgo biloba on central cognitive processes. Ginkgo biloba extract can be used as treatment of memory related diseases.
In a triple blind, placebo controlled study, efficacy of Ginkgo biloba was assessed in twenty-four patients with history of erectile dysfunction associated with antidepressants. Based on the observations statistically no significance difference was observed in the treatment and side-effects.
A comparative clinical-trial evaluating effect of dosages of 120 mg and 240 mg of Ginkgo biloba in patients showed a definite therapeutic benefit on pain free walking distance with 240 mg.
Another two placebo- controlled trials, involving 190 patients, demonstrated decreased pain and improved walking distance in patients diagnosed with peripheral vascular disease (PVD).
In a study fifty-four patients diagnosed with chronic refractory schizophrenia, twenty-seven were treated with haloperidol plus Ginkgo biloba, and the rest received haloperidol + placebo. Based on the observations it was concluded that Ginkgo biloba may enhance the efficacy of haloperidol on schizophrenia, especially on positive symptoms.
- A recent clinical study done on 1,121 patients on basis of using telephone interviews and questionnaires, failed to show a benefit of ginkgo in the treatment of tinnitus. The pattern however did not use the standard procedure (audiometric testing) as an outcome for measuring difference.
- In yet another randomized using Ginkgo biloba, placebo-controlled trial, 103 patients diagnosed with new-onset tinnitus showed fifty percent improvement or even disappearance of clinical symptoms in 70. In case of placebo, participants took 119 days to show improvement as compared to the Ginkgo biloba group.
An open trial of cedemin, a Ginkgo biloba extract with PAF-antagonistic effects for ulcerative colitis has been reported but details are missing.
A study reported effect of concentrated oral liquor of Ginkgo biloba in the treatment of bronchial asthma but details are missing.
A double blind study reported efficacy of Ginkgo biloba in protecting against hypoxia (Schaffler, V. K. & P. W. Reeh. 1985).
A study reported favorable effect of Ginkgo biloba in senile macular degeneration.
A clinical study demonstrated favorable effect of Ginkgo biloba in the treatment of mountain-sickness and reactivity of vascular system on exposure to cold.
In an open study, polysomnographic effect of Ginkgo biloba as an adjuvant therapy with tricyclic antidepressant, trimipramine was investigated in patients suffering from severe depression. The authors reported favorable response of Ginkgo biloba as an adjuvant to trimpramine in treating depression.
Side-effects: Gastric upset, hemorrhage, nephropathy, diarrhea, allergic skin rash or dermatitis, rarely spasms, cramps and atonia and adynamia.
Special precautions: Bleeding diathesis.
Dose: Powder (A standardized extract containing 24% Ginkgo flavonglycosides of 40 mg thrice-a-day).
Special note: Ginkgo has shown to increase production of adenosine triphosphate, resulting in increased cerebral glucose metabolism.
Cohen, A.J. & Bartlik, B. (1998). Ginkgo biloba for antidepressant-induced sexual dysfunction. Journal of Sex and Marital Therapy 24: 139-143.
Drew, S. & Davies, E. (2001), Effectiveness of Ginkgo biloba in treating tinnitus: double blind, placebo controlled trial. BMJ 2001; 332:73.
Drew, S. & Davies, E. (2001), Effectiveness of Ginkgo biloba in treating tinnitus: double blind, placebo controlled trial. BMJ.; 322(7278):73.
Hemmeter, U et al., (2001), Polysomnographic effect of Ginkgo biloba as an adjuvant therapy in patients with major depression medicated with trimipramine. Pharmacopsychiatry; 34(2); 50-9.
Hindmarch, I. (1988). Activity of Ginkgo biloba Extract on Short-term Memory. In E. W. Funfgeld (ed.) 1988. Op. cit. Pp. 321-326.
Hofferberth, B. (1994). The efficacy of EGb 761 in patients with senile dementia of the Alzheimer type, a double-blind, placebo-controlled study on different levels of investigation. Human Psychopharmacology 9: 215-222.
Kleijnen,J. & Knipschild P, (1992), Ginkgo biloba for cerebral insufficiency. Br. J Clin Pharmac 35: 352-358.
Winther, K., Randlov, C., Rein, E. et al. (1998). Effects of Ginkgo biloba extract on cognitive function and blood pressure in elderly subjects. Current Therapeutic Research 59: 881-888.
Zhou, D. et al., (1999), The effects of classic antipsychotic haloperidol plus the extract of Ginkgo biloba on superoxide dismutase in patients with chronic refractory schizophrenia. Chin Med J (Engl) 1999 Dec; 112(12): 1093-6.