A comparative study of commercial samples of ephedrae herba.

A total of 22 commercial Ephedra herba samples which belonged to EPHEDRA SINICA, E. INTERMEDIA, E. EQUISETINA, and E. DISTACHYA, respectively, were collected from the Taiwan herbal market. The contents of the six ephedrine alkaloids - ephedrine (E), pseudoephedrine (PE), methylephedrine (ME), methyl-pseudoephedrine (MPE), norephedrine (NE), and nor-pseudoephedrine (NPE) - in these samples were determined by capillary electrophoresis and were found to differ greatly among the samples. Generally, E. SINICA was superior (1.594 +/- 0.467%) and E. INTERMEDIA was inferior (1.210 +/- 0.372%). Among the individual constituents, the sum of E and PE contents in each sample was about nine-tenths of the total alkaloids, and the ratios of E/PE, ME/MPE, and NE/NPE in the given species were definite and could be used to aid in identifying the origin of the herbs. The alkaloid contents were found to be higher in the internodes of the herbs and in those items with thin stems, more powdery and less fibrous characters. There were no indications for alkaloids in the roots of the plants.