Q: What is Ginko Biloba and what is it good for? - Layperson

In Traditional Chinese pharmacopeia the seeds (with fleshy rind removed) are considered more important than the leaves. The nut, called Pak Ko, is recommended to expel phlegm, stop wheezing and coughing, urinary incontinence and spermatorrhea. The raw seed is said to help bladder ailments, menorrhea, uterine fluxes, and cardiovascular ailments. The powdered leaf is inhaled for ear, nose, and throat disorders like bronchitis and chronic rhinitis. Locally applied boiled leaves are used for chilblains.. The seeds are used as an astringent for the lung, to stop asthma and enuresis.

Ginkgo leaves are a Chinese herb that has been used much more in the West than in its homeland. Over five hundred scientific studies on the chemistry, pharmacology and clinical effects of gingko leaves have been conducted by European researchers over the last 20 to 30 years. The majority of studies on ginkgo leaf extract have involved a product produced by a German/French consortium, referred to in the scientific literature as EGb761.

The extract utilized in medicine is standardized in a multi-step procedure designed to concentrate the desired active principles from the plant. These extracts contain approximately 24% flavone glycosides (primarily composed of quercetin, kaempferol, and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B, and C, and 2.6-3.2% bilobalide). Other constituents include proanthocyanadins, glucose, rhamnose, organic acids, D-glucaric acid and ginkgolic acid (at most 5 ppm ginkgolic acids). Biochemical studies have concentrated on the flavonoids: much of the curative properties of the ginkgo tree are due to the activities of these flavonoids. The complex extract itself, rather than a single isolated component, is believed to be responsible for Ginkgo's biological activity.

  Ginkgo standardized extracts have been widely used in Europe for a wide variety of clinical conditionsassociated with age-related physical and mental deterioration. These include:

1) Alzheimer's Disease / age-related dementia: Ginkgo extracts appear to be capable of stabilizing and, in some cases, improving the cognitive performance of patients with schizophrenia. Based on a quantitative analysis of the literature there is a small but significant effect of 3 to 6 month treatment with 120 to 240 mg of Gbe on objective measures of cognitive function in Alzheimer's Disease ( Oken, Oregon Health Sciences University, 1998 ). The last publication ( Le Bars, Memory Centers of America, New York, Jan 2002 ) indicated that " a treatment effect favorable to EGb could be observed with respect to cognitive performance and social functioning  regardless of the stage of dementia, whether mild or moderately severe. However, the relative changes from baseline measured at endpoint depended heavily on the severity at baseline. Improvement was observed in the group of patients with very mild to mild cognitive impairment, while in more severe dementia, the mean EGb effect should be considered more in terms of stabilization or slowing down of worsening, as compared to the greater deterioration observed with placebo". Further research in the area will need to determine if there are functional improvements and to determine the best dosage. Additional research will be needed to define which ingredients in the ginkgo extract are producing its effect in individuals with AD. A recent study makes clear that  EGb treatment may enhance the effectiveness of antipsychotic drugs and reduce their extrapyramidal side effects ( Zhang, Yale University School of Medicine, 2001 ).

2) Cardiovascular Disease: Treatment with Ginkgo biloba extract lowers fibrinogen levels and decreases plasma viscosity ( EGb can limit oxidative stress )

3) Cerebral vascular insufficiency and impaired cerebral performance: Administration of EGb has been shown to improve a variety of conditions associated with cognitive functions, particularly for memory loss, attention, alertness, vigilance,  reaction times and depressive mood. A recent australian study indicates significant improvements in speed of information processing working memory and executive processing attributable to the EGb ( Stough C, Swinburne University of Technology, Melbourne, 2001 ).

Other therapeutic applications include: 

1) Congestive symptoms of premenstrual syndrome: Ginkgo extract was effective for the treatment of the congestive (particularly breast symptoms) and neuropsychological symptoms of PMS.

2) Intermittent Claudication: A recent meta-analysis ( Pittler, University of Exeter, 2000 ) found a significant difference in the increase in pain-free walking distance in favor of Ginkgo biloba (weighted mean difference: 34 meters ). In studies using similar methodological features (ergometer speed: 3 km/h, inclination: 12%) this difference was 33 meters in favor of Ginkgo biloba.

3) Vertigo / Equilibrium Disorder / Prevention of altitude sickness.

4) Tinnitus (ringing in the ear). An overview ( Holstein, Karlsruhe, 2001 ) of results of 19 clinical trials shows a statistically significant superiority of treatment with the Gbe 761 as compared with placebo or reference drugs applied of periods of 1 to 3 months. " Therapeutic success was not directly correlated with either the genesis or the duration of tinnitus. However, investigations of prognostic factors revealed that short-standing disorders have a better prognosis, so that better results can be expected from early-onset treatment."

5) Liver Fibrosis: Ginkgo biloba was shown to be effective in arresting the development of liver fibrosis associated with chronic hepatitis B.

6) Macular degeneration: In spite of the small population sample, a statistically significant improvement in long distance visual acuity was observed in patients with macular degeneration.

Ginkgo's most powerful effect is on the circulating system. Ginkgo flavenoids directly dilate the smallest segment of the circulating system, the micro-capillaries, which increase both blood circulation and oxygen levels in the brain as well as in other critical organ tissues. Ginkgo also prevents platelet aggregation or clumping inside the arterial walls. This increases arterial wall strength and flexibility and decreases the opportunity for the formation of arteriosclerostic plague. Since ginkgo increases oxygen flow to the brain and enhances the brains uptake and utilization of glucose it also is being researched for its role in the senility, forgetfulness, headaches and Alzheimer's disease and its role in improving alertness, memory and mental performance.

Related to circulatory improvement, German researchers have also been studying ginkgo as a treatment for atheroclerotic peripheral vascular disease. This disease impairs walking and ginkgo has been shown to help blood flow to the legs allowing people to walk further with far less pain.

Aside from these critical, high profile circulatory effects, ginkgo also increase the body's ability to produce the universal energy molecule adenosine triphosphate (ATP). This can in turn, decrease fatigue and listlessness.

Ginkgo is a highly important antioxidant shown to have a special affinity for scavenging the superoxide radicals. Due to its antioxidant role, ginkgo can increase cellular longevity, protect against pulmonary disease, provide membrane stability, and support ocular strucular integrity (i.e.. prevent maculos degeneration).

There are a variety of different Ginkgo Biloba raw materials available to manufacturers for use in brand name products. The raw materials chosen is a key in the effectiveness of the final product.

Ginkgo leaves should be hand picked to insure that the plant's terpene rich veins are not distroyed. Once harvested, the leaves need to be dried to an extract moisture level to maintain active constituent potencies. After drying the leaves must be stored in temperature and humidity controlled warehouses until the extraction process occurs. Following extraction, there should be a guaranteed potency of a minimum of 24% ginkgoflavonglycosides and 6% total terpenelactones.