Gastrodia

Description

Gastrodia is a preparation made from the rhizome or tuber of an orchid, Gastrodia elata. It is a member of the Orchidaceae family. Gastrodia elata is a native of the Far East; its natural areas of distribution include Tibet, western China, Korea, and Japan. While gastrodia appears in the oldest lists of Chinese medicinal herbs, it was not known to Western herbalists.

Gastrodia is first mentioned in the Shennong Bencao Jing, which was compiled around a.d. 100. A later Chinese herbalist named Tao Hong placed gastrodia in the category of superior herbs, which meant that it could be taken for long periods of time, and that it could be used to promote longevity as well as to treat illnesses. It was originally called chiqian, which means "red arrow" in Chinese, because its stem is red and arrow-shaped. Later it was named tian ma, or "heavenly hemp," which is the name that it still bears in Chinese herbal formularies.

Like other wild orchids, Gastrodia elata has been placed on the list of endangered species. The increasing difficulty of finding wild gastrodia in the 1970s led to an interesting discovery about this plant. Chinese herbalists tried to cultivate gastrodia, but failed until biologists discovered that the plant needs two fungi in order to survive and reproduce. It needs the Armillaria mellea mushroom on its tuber in order to grow and mature; and it requires a second fungus called Mycena osmundicola to help its seeds to sprout. After this complicated relationship was understood, herbalists were able to grow gastrodia.

Another aspect of this discovery was the finding that most of the medicinal benefits associated with gastrodia are actually produced by the Armillaria mushroom. Many growers then decided to cultivate the mushroom by itself without the gastrodia tuber. Some herbalists now use the Armillaria mushroom in their preparations instead of wild or cultivated gastrodia.

General use

In the categories of Chinese herbal medicine, gastrodia is classified as having a sweet and slightly warm nature with a neutral taste. Its traditional uses are to calm the liver and to clear the meridians by invigorating the patient's circulation. In the categories of Western medicine, gastrodia is said to have sedative and analgesic properties. The specific conditions that were treated by gastrodia include migraine headaches, dizziness or vertigo due to liver inflammations, convulsions caused by heat excess, paralysis, general fatigue , numbness in the hands or feet, and pain in the joints. More recently, gastrodia has been used to relieve nervous headaches, pain in the trigeminal nerve, nocturnal emissions, difficult breathing, insomnia due to stress , and hypertension .

Chemical analysis of gastrodia indicates that it contains significant amounts of calcium, magnesium , and potassium . Its active ingredients include gastrodioside, vanillin (from the rhizome), and vanillyl alcohol (from the tuber). These last two compounds are related to vanilla flavoring, which comes from another orchid called Vanilla plantifolia. Research indicates that vanillin has anticonvulsive properties. Other research suggests that the gastrodia tuber has analgesic and sedative effects because the compounds in it decrease the level of dopamine in the brain. Most of the other traditional Chinese uses for gastrodia have not been corroborated by research.

Preparations

Single-herb preparations

Gastrodia preparations are made from the tubers and rhizomes, or underground stems, of the plant. The rhizomes are dug in winter or spring. The bark is then removed and the rhizomes are cleaned and boiled, or steamed and baked. They are soaked in water a second time and sliced. In traditional Chinese herbal medicine, gastrodia is given as a decoction (concentration of herb after boiling down), in doses of 3–10 g per day.

The Armillaria mushroom that is necessary for the growth of the gastrodia tuber has been given the Chinese name of tian ma mihuanjun. It is more potent than the gastrodia tuber because it is the source of the tuber's active compounds. Although exact comparisons have not yet been determined, most Chinese practitioners use about half the customary dosage of gastrodia when they are replacing it with Armillaria. The mushroom or the gastrodia tuber are given in powdered form, in doses of 1.0–1.5 g, two or three times per day.

Herbal formulas

Gastrodia has been a favorite herb to use in combination formulas to treat specific conditions. Most of these formulas are made up as tablets or capsules. A Chinese pharmacology textbook lists the following herbal mixtures containing gastrodia:

• For dizziness and headache caused by a hyperactive liver: gastrodia combined with uncaria and haliotis.
• For disturbances caused by wind-phlegm: gastrodia with pinellia and atractylodes.
• For migraine: gastrodia combined with cnidium.
• For convulsions caused by liver heat: gastrodia with antelope horn and uncaria.
• To clear the meridians and relieve pain or numbness in the limbs: gastrodia combined with achyranthes, chin-chiu, and chiang-huo.

Precautions

Gastrodia is considered a mild herb by the Chinese, and therefore generally safe to use. It is best, however, to consult an experienced practitioner of Chinese herbal medicine before using gastrodia either as a single herb or in formulas.

Side effects

One source reports that the side effects of gastrodia include skin allergies, hair loss , and other allergic reactions.

Interactions

Because gastrodia has not been used by Western herbalists, its potential interactions with standard pharmaceutical preparations have not been studied.

Resources

BOOKS

Reid, Daniel P. Chinese Herbal Medicine. Boston: Shambhala, 1993.

ORGANIZATIONS

American Association of Oriental Medicine (AAOM). 433 Front Street, Catasauqua, PA 18032. (610) 266-2433.

American Foundation of Traditional Chinese Medicine (AFTCM). 505 Beach Street, San Francisco, CA 94133. (415) 776-0502. Fax: (415) 392-7003. [email protected].

OTHER

Dr. James A. Duke. Phytochemical and Ethnobotanical Databases. United States Department of Agriculture, Agricultural Research Service. Beltsville Agricultural Research Center. Beltsville, MD.

Rebecca J. Frey, PhD