ephedra(redirected from Ma juang)
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, drug derived from plants of the genus Ephedra (see Pinophyta), most commonly used to prevent mild or moderate attacks of bronchial asthma. Unlike epinephrine, to which it is chemically similar, ephedrine is slow to take effect and of mild potency and long
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a genus of gymnospermous plants of the family Ephedraceae. The plants are mostly low, strongly branched shrubs (sometimes lianoid) and small trees reaching 8 m in height. The shoots are virgate and segmented. The opposite leaves are small and usually reduced; the function of photosynthesis is taken over by the young branches. The strobili are unisexual. The staminate ones consist of an axis with two to eight pairs of bracts, whose axils bear microstrobili. The pistillate strobili consist of a seed embryo enclosed by a saclike cover.
There are more than 40 species, occurring in Eurasia, North Africa, and North and South America. They are found primarily in steppe, desert, and mountain regions. The USSR has about 15 species, occurring mainly in Middle Asia. E. equisetina and other species contain the alkaloid ephedrine, which is used in medicine. The branches of E. distachya are a popular remedy for rheumatism and other diseases; sheep are sometimes poisoned by the green branches of the species. The succulent seeds of some species are edible.
M. E. KIRPICHNIKOV