|
Ephedra sinica, Ephedraceae. The common name is ephedra and the Chinese name
is ma huang.
Ephedra has been used in traditional Chinese medicine for 5,000 years. The
root of the plant is also used in TCM, but for other ailments. Western herbal
tradition had little reference to the plant. Ephedrine was isolated from the
plant in the late 1800s, but it was not until the 1920s that it became pharmaceutically
popular.
There has been a good deal of public press on Ephedra and ephedrine in recent
years. Much of the concern focusing on the use of ephedrine-containing diet
pills and stimulants pills, which have become popular among young people. There
have been several deaths in which these products have been implicated. The
other major problem is the possibility of methamphetamine production from the
either ephedrine or the herb Ephedra. Fourteen states have regulated the sale
of ephedrine, but there is some debate about the regulation of Ephedra, the
herb.
There are 40 species within the family Ephedraceae that
grow in China, India, Egypt, the Middle East, Europe and the Americas. They
are an evolutionary primitive group of shrubs that grow on dry, rocky or sandy
terrain in desert or arid areas. Although Ephedra sinica (from China) is the
primary medical species, E. equisetina is another Chinese variety of commercial
importance. The American variety, E. antisyphilitica, from the Southwest, was
popularized by the Mormon’s in Utah and called Mormon tea or Brigham Young tea.
This plant, however, contains none of the pharmacological alkaloids of the Chinese
plant.
The plant is a low growing, evergreen, almost leafless
shrub that grows up to three feet tall. The stems, that branch from the base,
are erect, longitudinally striated with internodes at regular intervals. Small
triangular leaves grow at these nodes. The plant is strongly aromatic, with
a bitter taste.
The dried stems is the part of the shrub that is used. It is available in
bulk herb, capsules, hydroalcoholic extract and is often found in weight loss
and energy formulas.
Alkaloids are the main active ingredients of Ephedra, primarily ephedrine and
pseudoephedrine. Ephedrine is similar in action to epinephrine (adrenaline)
in the body. It stimulates the central nervous system and sympathetic nervous
system, causes vasoconstriction, cardiac stimulation (increased cardiac output,
heart rate and blood pressure) and bronchodilation. It stimulates alpha, beta
1 and bera 2 adrenergic receptors.1
Ephedrine also exerts its effect on dopamine receptors and is used in the treatment
of narcolepsy.2
Ephedrine is also used for weight loss, when combined with methylxanthines and
salicylates, it is claimed be thermogenic.3
Pseudoephedrine acts similar to ephedrine except its hypertensive and CNS stimulation
are weaker. It also demonstrates anti-inflammatory effects4.
The German Commission E approves Ephedra for diseases of the respiratory tract
with mild bronchospasms.5
It is commonly used as a bronchodilator and anti-asthmatic. In China it is
used (combined with other herbs) for treatments of colds, influenza, pneumonia,
whooping cough, and bronchitis.6
Ephedra has become a popular ingredient of weight loss and energy products.
It has also become a substance of abuse in products such as Herbal Ecstasy,
that are purported to give a natural high, and have been linked to a number
of deaths.
The alkaloidal content of Ephedra varies considerably
depending upon varieties, altitude, weather conditions and time of harvest.
It generally contains a total of 0.5 to 2.5 percent of a group of alkaloids
referred to as ephedra alkaloids, with ephedrine being about 30 to 90 percent
of that total.7 These alkaloids
consist of ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, methylephedrine
and methylpseudoephedrine. Other constituents include tannins, saponins, proanthocyanidins,
phenolic acids, flavonoids and essential oils.8
The German Commission E recommends herbal preparations
corresponding to 15 to 30 mg. of ephedrine per dose, with a daily dosage not
to exceed 300 mg. total alkaloid. The FDA recommends a maximum daily dose of
150 mg. Tea made with one teaspoon of good quality Ephedra herb to one pint
of water should yield approximately 15 to 30 mg of ephedrine. The hydroalcoholic
extract dosage would depend on the strength of the extract.9 The FDA also recommends it not be used
over one week at a time.
Excessive or long term use of ephedra is to be
avoided. Ephedra should be discontinued if increased blood pressure, heart
rate or anxiety occurs. It should not be used with any of the following conditions:
high blood pressure, gastric ulcers, heart disease, stimulant sensitivities,
pregnancy, lactation, diabetes, thyroid dysfunction and difficulty in urination
due to enlarged prostate.
In large doses ephedra can cause nervousness, headaches,
vomiting, insomnia, dizziness, palpitations, tachycardia, increased blood pressure,
skin flushing, anxiety and agitation. There has been recent reports that ephedrine
can cause nephrolithiasis.10 Ephedra is contraindicated
with cardiac glycosides or halothane because it can disturb the heart rhythm.
Combined with Guanethidine it can enhance sympathomimetic effects. Usage should
be avoided with MAO-inhibitors.11
1 Blumenthal
Mark, King, Penny. “Ma Huang: Ancient Herb, Modern Medicine, Regulatory Dilemma”.
Herbalgram; 34. Summer 1995. 24.
2 Robson, Terry.
“Ephedra Sinica et spp.” Australian Journal of Medical Herbalism; 7(3).
1995.
3 Blumenthal
Mark, King, Penny. “Ma Huang: Ancient Herb, Modern Medicine, Regulatory Dilemma”.
Herbalgram; 34. Summer 1995. 24.
4 Hiroshi Hikino,
et al. “Antiinflammatory Principle of Ephedra Herbs”. Chemical Pharmacological
Bulletin; 28(10). 1980. 2900-4.
5 Blumenthal,
Mark, et al. The Complete German Commission E Monographs. American
Botanical Council, Texas. 1998.125-126.
6 Robson, Terry.
“Ephedra Sinica et spp.” Australian Journal of Medical Herbalism; 7(3).
1995.
7 Blumenthal
Mark, King, Penny. “Ma Huang: Ancient Herb, Modern Medicine, Regulatory Dilemma”.
Herbalgram; 34. Summer 1995. 23.
8 Robson, Terry.
“Ephedra Sinica et spp.” Australian Journal of Medical Herbalism; 7(3).
1995.
9 Blumenthal
Mark, King, Penny. “Ma Huang: Ancient Herb, Modern Medicine, Regulatory Dilemma”.
Herbalgram; 34. Summer 1995. 25.
10 Powell, T,
et al. “Ma-huang strikes again: ephedrine nephrolithiasis”. American Journal
of Kidney Disease: 32(1). Jul 1998. 153-9.
11 Blumenthal,
Mark, et al. The Complete German Commission E Monographs. American
Botanical Council, Texas. 1998.125-126.
|
|