Ma Huang/Ephedra contains ephedrine. Sudafed contains pseudoephedrine which is a stereoisomer (I forget whether it’s an ordinary stereoisomer or if it’s a diastereoisomer). The difference between them is in the configuration of the amine group. Both compounds exert a stimulatory effect on the central nervous system (CNS), and both have peripheral effects within the peripheral nervous system (PNS) such as drying out the mucous membranes- which is the basis of their status as cold remedies. Ephedrine has less of a PNS and more of a CNS effect than does pseudoephedrine, which is why ephedrine is sold at truck stops to keep truckers awake, and pseudoephedrine (Sudafed) is sold as the cold remedy. (Not that pseudoephedrine can’t get you all jumpy and wired- believe me, it sure can if you take enough!)
There seems to be a common misconception among the proponents of alternative medicine that the "medical establishment" and the "giant pharmaceutical companies" are simply unwilling to concede that plants contain pharmaceutically active compounds in them. Which is silly, especially when you consider that pharmaceutical companies are always teasing new drugs from all kinds of plants around the world. But while plants may indeed be "all-natural", the problem is that they don't supply a fixed, certain dosage of pharmaceutically active material, they often contain unknown amounts of other alkaloids which aren't as researched, they don't come with warning labels, and they are unregulated.
For example, there are a lot of prescription and nonprescription drugs that have warnings on their labels: “Do not take this medication along with an MAO inhibitor”. Now “MAO” is monoamine oxidase- it is a “cleanup” enzyme within the CNS and PNS that inactivates stray neurotransmitters that have leaked away from their synapses. MAO inhibitors were the first class of medications that were found to be useful in combatting depression. (As an historical footnote, there is an interesting story here. The first MAO inhibitors were imperfect, and suppressed not only “brain MAO”, which is used in the CNS- thus treating depression, but also “body MAO”, which is used by the PNS, and which should not be monkeyed with. Patients taking these first drugs suddenly had their cloud of depression lifted. A few of them got really happy, and decided to throw themselves little parties with their friends, complete with wine and cheese. Both wine and cheese contain tyramine. As a result of their body MAO being inhibited, the tyramine killed them. This was known as the “wine and cheese” effect. It was eliminated when CNS-specific MAO inhibitors were developed.)
The MAO inhibitors were succeeded by later classes of antidepressants such as the tricyclics, and after that, Prozac and the other SSRIs. Now they are rarely used. They are considered the antidepressant of last resort because of their side effects. In fact, if you are taking an MAO inhibitor, there are many drugs that you shouldn’t take since they may induce seizures or cause other neurological complications.
But you can buy Saint John’s Wort without a prescription. The label says that the St. John’s Wort herbal tablets are a “dietary supplement”. What they don’t say is that Saint John’s Wort is an MAO inhibitor.
“Who are all you people, and how did you get in my computer?”