Sources and Chemical Composition

Ephedra (epherdre du valais in French and Walliser meertraubchen in German) is a small perennial shrub with thin stems. It rarely grows to more than a foot in height, and at first glance, the plant looks very much like a small broom. Different, closely related species are found in Western Europe, southeastern Europe, Asia, and even the Americas. Some of the better known species include Ephedra sinica and E. equisentina from China (collectively known as ma haung), as well as E. geriardiana, E. intermedia, and E. major, which grow in India and Pakistan, and countless other members of the family Ephedraceae that grow in Europe and the United States (E. distachya, E. vulgaris) (20).

Ephedra species vary widely in their ephedrine content. One of the most common Chinese cultivars, known as "China 3," contains 1.39% ephedrine, 0.361% pseudoephedrine, and 0.069% methylephedrine (21). This mix is fairly typical for commercially grown ephedra plants. Noncommercial varieties of ephedra may contain no ephedrine at all (22), while others may contain more pseudoephedrine than ephedrine. Depending on the variety, trace amounts of phenylpropanolamine, (-) norephedrine, and methylephedrine may also be present, however (+) norephedrine does not occur naturally, and its presence is proof of adulteration.

Labels on herbal supplements listed total ephedra alkaloid content, usually 10 or 11 mg per serving. Depending on the raw materials used, different production runs of the same product contained ephedrine and pseudoephe-drine in varying proportions. Occasionally, supplement makers were accused of adulterating their product by adding synthetic ephedrine or pseudoephe-drine. Unlike with (+)-norephedrine, these compounds occur naturally and product adulteration should not have been alleged just because alkaloids other than ephedrine were detected in trace amounts, or because the ratio of ephedrine to pseudoephedrine was close to, or even greater than, 1:1. Of course, if one of the minor alkaloids, such as methylephedrine, were found to be present in concentrations approaching those of ephedrine, the ratio could only be explained by adulteration.

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