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The history of Ephedra (ma-huang)

2011; SAGE Publishing; Volume: 41; Issue: 1 Linguagem: Inglês

10.4997/jrcpe.2011.116

2042-8189

MR Lee,

Hormonal and reproductive studies

Early historyEphedra (ma-huang) is a Chinese shrub that has been known for at least 5,000 years.The Chinese emperor Shen Nung, around 2,700 BC, catalogued 365 herbs in terms of their bitterness, the main groups being strong, medium and mild.Ma-huang, whose literal translation means 'hemp yellow', was placed in the medium group.In the latter part of the sixteenth century, Li Shih-Chen produced a famous dispensatory, the Pents'ao Kang Mu, in which the shrub is clearly described. 1,2Ephedra was said to be useful as a circulatory stimulant, a diaphoretic and an antipyretic.It was also believed to be useful in the treatment of cough and as a result the stem became an important ingredient of many antitussive preparations.At the end of the sixteenth century the dried stems were exported to Japan, a trade which was to play an important part in stimulating the interest of Japanese physicians and chemists in the plant some three hundred years later.Other species of Ephedra (later recognised as E. pachyclada and E. intermedia) which were thought to have medicinal value were found in Greece, Russia, India and the Americas.Various religious groups, including Hindus and Parsees, used them in their ceremonies to produce feelings of exhilaration.Ephedra acts as a central nervous excitant as a result of the rapid passage of ephedrine through the blood-brain barrier.This stimulates neurons in the limbic system, which also control part of the hypothalamus (supporting a variety of functions, including emotion).As the preparations used by Indian religious sects also contained ethyl alcohol it is impossible in retrospect to know how much of the ecstatic experience was due to alcohol, how much to ephedrine and how much to the interaction between the two psychostimulants.In the Americas, a number of other Ephedra species were known to the indigenous people.These were later classified as E.antisyphilitica, E. californica and E. nevadensis. 3They were thought to act against syphilis and gonorrhoea and were applied either directly to the genital organs or taken by mouth. 3E. nevadensis had some interestingThe history of Ephedra (ma-huang) aBstraCt Ephedra is a Chinese shrub which has been used in China for medicinal purposes for several thousand years.The pure alkaloid ephedrine was first isolated and characterised by Nagai in 1885.It was then forgotten until it was rediscovered by Chen and Schmidt in the early 1920s.Its actions on the adrenoceptors could be classified into separate alpha and beta effects -a defining moment in the history of autonomic pharmacology.Ephedrine became a highly popular and effective treatment for asthma, particularly because, unlike adrenaline (until then the standard therapy), it can be given by mouth.Ephedrine as a treatment for asthma reached its zenith in the late 1950s, since when there has been a gradual and inevitable decline in its therapeutic use.From mainstream medicine, ephedrine moved into the twilight zone of street drugs and nutritional supplements.Ephedra and ephedrine products are now banned in many countries, as they are a major source for the production of the addictive compound methamphetamine (crystal meth).