Ephedrine (EPH) is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia. Ephedrine is similar in structure to the synthetic derivatives amphetamine and methamphetamine. Chemically, it is an alkaloid derived from various plants in the genus Ephedra (family Ephedraceae). It is most usually marketed in the hydrochloride and sulfate forms.

In traditional Chinese medicines, the herb má huáng (麻黄, Ephedra sinica) contains ephedrine and pseudoephedrine as its principal active constituents. The same is true of other herbal products containing extracts from Ephedra species. Nagayoshi Nagai was the first one to isolate ephedrine from Ephedra distachya (syn. Ephedra vulgaris) in 1885. The substance called soma mentioned in old Hindu books such as the Rig Veda, may have been ephedra extract. This, however, is disputed, as the identity of soma.

The production of ephedrine in China has become a multi-million dollar export industry. Companies producing for export extract US$13 million worth of ephedrine from 30,000 tons of ephedra annually, 10 times the amount that is used in traditional Chinese medicine. Long, Professor. http://www.chinadialogue.net/article/show/single/en/692-Chinese-medicine-s-great-waste-of-resources

Chemistry

Ephedrine exhibits optical isomerism and has two chiral centres. By convention the enantiomers with opposite stereochemistry around the chiral centres are designated ephedrine, while pseudoephedrine has same stereochemistry around the chiral carbons. That is, (1R,2R)- and (1S,2S)-enantiomers are designated pseudoephedrine; while (1R,2S)- and (1S,2R)-enantiomers are designated ephedrine.

The isomer which is marketed is (-)-(1R,2S)-ephedrine.

As with other phenylethylamines, it is also somewhat chemically similar to methamphetamine, although the amphetamines are more potent and have additional biological effects.

Ephedrine may also be referred to as: (αR)-α-1benzenemethanol, α-2benzyl alcohol, or L-erythro-2-(methylamino)-1-phenylpropan-1-ol. Ephedrine hydrochloride has a melting point of 187-188°C.Budavari S, editor. The Merck Index: An encyclopedia of chemicals, drugs, and biologicals, 12th edition. Whitehouse Station: Merck

Mechanism of action

Ephedrine is a sympathomimetic amine, the principal mechanism of its action relies on its direct and indirect actions on the adrenergic receptor system, which is part of the sympathetic nervous system or SNS. Central nervous system or CNS involvement is present, but the predominant clinical effects are caused by involvement with the sympathetic segment of the peripheral nervous system because while ephedrine does cross the blood-brain barrier, it doesn't do this very efficiently (efficient crossers with similar modes of action would include amphetamine and methamphetamine).