Ephedrine and other ephedrine alkaloids are phenylalkylamines, which are organic compounds consisting of a phenyl group, a carbon chain, and an amine group. To see their structures, simply click on the following links (a pop-up window will open): ephedrine, norephedrine, pseudoephedrine, norpseudoephedrine, and methylephedrine. These compounds constitute the active elements of plants belonging to the genus Ephedra (Lee et al., 2000). They are biosynthesized in the stems of many Eurasian species of Ephedra through the decarboxylation of phenylalanine and tyrosine. Among these plants, ephedrine alkaloids are found in varying amounts. In addition to Ephedra plants, ephedrine alkaloids, predominantly norpseudoephedrine, are found in khat (Catha edulis), which is a plant native to the Arabian peninsula. In Eurasian Ephedra plants, collectively referred to as Ma Huang, the two most prevalent ephedrine alkaloids are ephedrine and pseudoephedrine (Caveney et al., 2001).

It has been suggested that ephedrine alkaloids serve a two-fold protective purpose in plants: 1) since ephedrine levels build up towards the end of the growing season, they might serve to protect the stem from UV radiation, 2) ephedrine is a known toxin to weevils (Caveney et al., 2001). In traditional Chinese Medicine, Ma Huang is taken in whole-herb form. However, in a recent study, the powder form was found to be significantly more toxic to human, mouse, rat, and hamster cell lines. Interestingly enough, pre-commercial Ma Huang is mainly distributed in powder form (Lee et al., 2000).

© Copyright 2001 Department of Biology, Davidson College, Davidson, NC 28036. Send comments, questions, and suggestions to: jokogoy@davidson.edu