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EPHEDRA [麻黃, MA HUANG]

Name : Ephedraephedraviridis-Foto_Dan Nickrent_opt

Chinese Name : 麻黃

Latin Name : Herba Ephedrae

Overview

This herb is the dried herbaceous stem of Ephedra sinica Stapf, E. Intermedia Schrenk et C.A.Meyer, or E. equisetina Bge, of the family Ephedraceae. It is mainly grown in the Hebei,Shanxi, Gansu, Liaoning, and Sichuan provinces and Inner Mongolia of China, where it is harvested in autumn, cleaned, dried, cut into segments, and used unprocessed or stir baked with honey. Processed ephendra is called jiao ma huang (processed ma huang)

Ephedra has been used for more than 2.000 years in Chinese medicine as a popular diaphoretic and antipyretic for colds and flu, fevers (particularly malarial fever), bronchial asthma, coughs, and breathing difficulties. It is also used traditionally to relieve edema.

The unprocessed ma huang is more effctive as a diaphoretic and diuretic medicine whereas the honey-stir-baked-processed  jiao ma huang is preferred for coughs, and to relieve asthma and dyspnca.

Ephedra’s use as a cardiac stimulant was adopted by Western medicine after K.K.Chen’s discovery in 1942 of ephedra’s cardiotonic and CNS stimulating properties, which are similar to epinephrine. In Chinese Medicine, ephedra has never been used as a cardiac stimulant or for weight loss, even today.

Use of Ephedra in TCM

Pungent and bitter in taste, and warm, it acts on the lung and urinary bladder meridians.

Effects, Medicial Uses, And Cominations.

  1. Disperses exopathogens and induces diaphoresis:
  • For Wind-Cold-type common colds, acute bronchitis, headaches, and fever with little sweating, ephedra is used alone in a decoction or with cinnamon twig, bitter apricot kernel, and licorine root, as in Ma Huang Tang.
  • To treat Wind-Cold-type affictions, headaches, coughs, sore throats, and stuffy noses, ephedra is blended with platycodon, perilla leaf, bitter almond, pinellia, and poria, as in Tong Xuan Li Fei Pian (R-47).
  • For Wind- Cold-Damp arthritis or chills without perspiration, ephedra is prescribed with white atractylodes and cinnamon twig.
  1. Invigorates the Lung-Qi and relieves bronchial asthma. To treat a cough with dyspnea and asthma, ephedra is combined with licorice root and bitter apricot kernel in a decoction. Ephedra is also blended with asarum, dry ginger, licorice root, cinnamon twig, white peony, schisandra, and pinellia tuber, as in Xiao Qing Long Tang (R-63), for a cough with profuse thin sputum. This recipe is used for common colds, bronchitis, bronchial asthma, and emphysema.
  2. Induces diuresis and reduces edema. To treat general nephrotic edema, ephedra is often used with licorice root and the lateral root of aconite.

Dosage

In a decoction of 5 to 10 g.

Precaution

Ephedra is a strong diaphoretic and cardiac stimulant, and must be used with caution. Do not overdose and avoid prescribing to patients who have night sweating, sweating due to yin deficiency, who are hypertensive, and have heart disorders. Its use should not be continued over a long period lest it weaken the body or become habit forming. Pregnant women shoud avoid te use of ephedra.

Side effects and toxicity

At the suggested therapeutic dose, it does not produce side effects. However, large doses or an overdose may  cause insomnia, anxiety, headaches, dizziness, tinnitus, nausea, vomiting, increased blood pressure, and heart palpitations (due to its CNS-activating and symathomimetic activities), anorexia, and urinary difficulties.

Chemical Constituents

The herb contains multiple (1 to 2 percent) organic alkaloids. Its most important constituents (about 40 to 90 percent) are I-ephedrine, d-pseudoephedrine, flavenes, and volatile oil. Other ingredients are ephedroxane, I-N-methylephedrine, d-nor-pseudoephedrine, I-n-methylephedrine, d-nor-pseudoephedrine, d-n-dimethylpseudo-ephedrine,beta-ephedrine, and I-alpha-d-terpinol.

Pharmacological Findings

  1. Diaphoretic and antifebrile.
  2. Coughing induced by stimulation of the tracheal or bronchial mucosa in anesthetized animals is suppressed by ephedra extract, or by ephedrine itself. Ephedrine produced stronger antitussive effects even in nonasthmatic subjects.
  3. Ephedra water or alcohol extract inhibits the release of histamines
  4. Similar to epinephrine but its action is milder and longer.
  • Ephedra dilates bronchioles and is spasmolytic
  • It relaxes the gastrointestinal smooth muscles and inhibits peristalsis
  • Ephedra is tensive on the uterine mucles in animals but relaxes human uterine muscles and relieves menstrual pain.
  • Increases the tension of the sphincter vesicae (the smooth muscle that controls the orifice of the bladder) and treats enuresis in children.
  1. Effects on the cardiovascular system:
  • Stimulates cardiovascular muscle, raises blood pressure, increases heartbeat, and augments arrhythmia.
  • Dilates cardiovascular, cerebrovascular, and muscular vascular systems, and increases blood flow.
  1. Ephedrine and pseudoephedrine increase the tone of skeletal muscles, and are useful in treating myasthenia gravis and fatigue.
  2. Ephedrine stimulates the respiratory, brain, and circulatory enters. Large doses cause stimulation, irritability, insomnia, and spasms. Pseudoephedrine has a strong diuretic effect. The volatile oil of ephedra is antifebrile, antiviral, and antimicrobial.

Clinical Findings

Currently, in world markets, pharmaceutical preparations containing ephedrine or the extract  of the ephedra herb are shrouded in confusion. Several analytical studies have shown that wide variations often exist between labeled and actual amounts of active constituents. In ephedra preparations, total alkaloid content has varied between 0 and 150 percent of the label claim.

The National Institutes of Health commissioned the RAND Corporation to conduct an exhaustive review of the scientific data on the safety of marketed ephedra products containing ephedrine or ephedra extract. In the United States, this included products under the brand names Metabolife, Xenadrine, and others. The study noted a strong link between these products and over 100 deaths, heart attacks, strokes, seizures, and serious psychiatric symptoms, as well as moderate side effects such as nausea, vomiting, jitteriness, arrhythmias, and palpitations. The investigaton concluded that there was no evidence to support the manufacturers’ claims that their products could enhance physical or athletic performance, long term weight loss, or weight maintenance. These ephedra products also contain stimulants, such as caffeine and amphetamines, other protent herbs with stimulating properties, vitamins, and minerals.