Ephedra equisetina

Ephedrine is an alkaloid that is present in various forms of the ephedrine family, and which is still extracted from Ephedra sinica and Ephedra equisetina. Because of the presence of two asymmetric atoms, there are four isomeric forms. Pseudoepinephrine (d-isoephrine) is a stereoisomer with pharmacological action that differs slightly from ephedrine. The pharmacological action of ephedrine is typical of noncatecholamine sympathomimetics of mixed action. It stimulates both a- and 8-adrenoreceptors, and simultaneously causes a release of norepinephrine from synaptic neurons. Its vasoconstrictive ability is approximately 100 times weaker than that of epinephrine however, the duration of action is approximately 10 times longer. It is much less toxic than epinephrine, which allows it to be used widely in medicine. 

This alkaloid was first isolated from Ephedra equisetina, a plant (ma huang) that has been used as medicine by the Chinese since antiquity. Most of the present supply is probably synthetic. Its chemical structure is closely related to epinephrine and tyramine, and differs from epinephrine chiefly by the absence of the two phenolic hydroxyls. Its effects on the circulation, intestines, bronchi, iris, etc., are superficially similar to those of epinephrine. It requires that larger doses be given but they are more lasting, due probably to ephedrine s much greater stability and resistance to oxidation. The effects can be produced by oral administration. Unlike epinephrine, it is not sensitized by cocaine or by denervation. From this, it has been argued that its point of attack is not sympathomimetic but muscular. It also stimulates the CNS. A number of isomers with similar actions are known. Ephedrine is used therapeutically in hay fever and asthma, in which it is less... 

Ephedra Equisetina, Ma Huang. Stems and Leaves of Ephedra equisetina Bunge, E sinica Stapf. and other species of Ephedra, Gnetaceae. Indigenous to China and India. ]t contains 0.75 to over 1% ephedrine it is the source of natural ephedrine. Contains also variable quantities of pseud oephed ri rt e. 

Feng and Read (104) found that the low yield of alkaloids obtained by previous workers was due to incomplete alkalinization of the herb before extraction with chloroform or ether. Hot extraction and the use of sodium hydrate to liberate the alkaloids has been found satisfactory. The ammonia-chloroform process has been critically studied and it was found that a large excess of ammonia was necessary to hberate the alkaloids. Feng (103) extracted Ephedra equisetina, first with 80% alcohol and finally with 0.2 % acetic acid. After working up the extracts, ephedrine was separated from f -ephedrine by crystallization of the hydrochlorides from 95% alcohol. -Ephedrine may be recovered from the mother liquors. Ghose and Krishna (114, 117, 118) described other methods of extraction and the preparation of alkaloid concentrates. They separated ephedrine from -ephedrine by extracting the dry hydrochlorides with chloroform, in which only the f -ephedrine salt is soluble. 

The Chinese herbal drug Mao (Japanese name Chinese name is Ma-huang) is prepared from the above-ground parts of Ephedra sp. plants, such as Ephedra equisetina. Ephedra distachya, and Ephedra sinica (Ephedraceae) which are native to China. Mao is used in Chinese traditional medicine prescriptions, and as a material for the preparation of ephedrine hydrochloride used for the treatment of cough. 

A wide variation exists in alkaloid content among different species of Ephedra in different parts of the world, with the highest total alkaloid content of 2.5 % in Ephedra equisetina. In fact, the yield of ephedrine in the extract of different species of Ephedra varies from 55 % to 83 % [10,13]. Cui and colleagues reported that the highest amount of ephedrine among different species analyzed was in Ephedra monosperma Gmel. Ex Mey (1.401 %), while the highest amount of pseudoephed-rine was in Ephedra intermedia Schrenk ex (0.912 %) [5] (Table 27.1). 

Ephedrine (l/ -25-2-methylamino-l-phenylpropan-l-ol) is an adrenergic amine present in many kinds of pharmaceutical preparations, obtained by synthesis or from natural sources. Belonging to the genus Ephedra (Ephedraceae), the Chinese species Ephedra sinica and Ephedra equisetina, also known as ma huang, and the Indian and Pakistani species E. gerardiana, E. intermedia, and E. major are the... 

Ephedra is the dried herbaceous stem of Ephedra sinica Stapf, Ephedra intermedia Schnenk et C.A. Mey. or Ephedra equisetina Bge. (Fam. Ephedraceae). 

Feng CT 1972 A method of preparing pure ephedrine hydrochloride from Ephedra equisetina Bge. Chin J Physiol 1 63-68... 

Tkraskina KV, Chumbalov TK, Ushakova MT, Anisimova AD 1966 Leukoephdine and ephdine from Ephedra equisetina and the study of their P-vitamin activity. Med Prom SSSR 20 27-29... 

Source Chinese ephedra Ephedra sinica Stapf. Intermediate ephedra Ephedra intermedia Shrenk et C. A. Mey. Mongolian ephedra Ephedra equisetina Bge. Other Ephedra spp. (Family Ephedraceae). 

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