Plants ephedra

Ephedrine is found in the ephedra plant (Ephedra sinica— the Chinese herb Ma Huang). It is used as a nasal decongestant... 

Orantine (ephedradine A) was isolated as a natural alkaloid from the crude drug mao, which itself is prepared from the aerial part of Ephedra plants (129). The structure, including the absolute configuration, was deduced by X-ray crystallography after preliminary chemical and spectroscopic work. The natural product and the isomerization product of aphelandrine (179) are also identical in their chiroptical properties (128). 

The alkaloid ephedradine B (191) was isolated from the crude drug mao-kon, prepared from the underground parts of Ephedra plants. Its structure, including absolute configuration, was deduced from spectroscopic analyses and chiroptic comparison of 189 and 191. Furthermore, spermine was isolated by hydrolysis of 191 (see Section V). 

Ephedra plants are erect, branching shrubs found in desert or arid regions throughout the world. The 1.5M ft shrubs typically grow on dry, rocky, or sandy slopes. The many slender, yellow-green branches of ephedra have two very small leaf scales at each node. The mature, double-seeded cones are visible in the fall. 

All ephedra plants contain phenylalanine-derived alkaloids, including ephedrine, pseu-doephedrine, methylephedrine, and trace amounts of phenylpropanolamine. Previously marketed herbal supplements typically stated total ephedra alkaloid content, although actual levels of individual alkaloid varied depending on raw material and production runs. 

The chemistry and nomenclature of these compounds are somewhat confusing, and are best understood by reference to the synthetic route used by plants to make ephedrine. All ephedra plants contain phenylalanine-derived alkaloids. Plants use phenylalanine as a precursor, but incorporate only seven of its carbon atoms. Phenylalanine is metabolized to benzoic acid, which is then acetylated and decarboxylated to form pyruvic acid. Transamination, results in the formation of forms (-)-cathinone. 

Ephedra species vary widely in their ephedrine content. One of the most common Chinese cultivars, known as China 3, contains 1.39% ephedrine, 0.361% pseudoephedrine, and 0.069% methylephedrine (21). This mix is fairly typical for commercially grown ephedra plants. Noncommercial varieties of ephedra may contain no ephedrine at all (22), while others may contain more... 

In the United States, (+)-norpseudoephedrine, in its pure form, is considered a Schedule IV controlled substance. However, because of the small amounts of this alkaloid in ephedra plants or extracts, the Drug Enforcement Administration (DEA) had never stated or proposed that ephedra products were subject to the scheduling requirements of the Controlled Substances Act. Quite the contrary, DEA published a proposed rule in 1998 that stated DEA s intent to exempt legitimate ephedra products in finished form from regulation even as chemical mixtures. Other regulatory sanctions and actions on ephedra rendered action on this regulation moot. 

NambaT, KuboM,Kanai Y,NambaK,NishimuraH, QazilbashNA. Pharmacog-nostical studies of Ephedra plants Part I—The comparative histological studies on... 

Ephedrine is the predominant alkaloid of ephedra plants. Other phenylalanine-derived alkaloids found in ephedra plants are (+)-pseudoephedrine, (—)-norephedrine, (-l-)-norpseudoephedrine, (l)-A-methylephedrine and phenylpropanolamines. Ephedrine is a potent central nervous system (CNS) stimulant. Because ephedra is both an a- and p-adrenergic agonist, ingestion of quantities over 50 mg lead to a rise in blood pressure, heart rate and cardiac output. 

All ephedra plants contain phenylalanine-derived alkaloids. These include (-)-ephedrine, (+)-pseudoephedrine, (-)-norephedrine, (+)-norpseudo-ephedrine (also called cathine because it is a major alkaloid of Catha edulis or khat, a plant used as a stimulant in North Africa), (-)-A-methylephedrine and (+)-A-methylpseudoephedrine, (+)-pseudoephedrine, and (+/-)-norephedrine (phenylpropanolamine). Significant enantioselective differences with regard to both pharmacokinetic and pharmacodynamic effects of these agents are possible. All of these alkaloids have important effects on the cardiovascular and respiratory systems, but not to the same degree. 

Namba T, Kubo M, et al. Pharmacognostical studies of ephedra plants part I — the comparative histological studies on ephedra rhizomes from Pakistan and Afghanistan and Chinese crude drugs "Ma-Hung-Gen." PlantaMed 1976 29 216-25. 

In specially collected ephedra plants total alkaloid yields as high as 3.4% have been observed (142). A good grade of Ma Huang should yield 2% of total alkaloids (111) but the commercial product usually contains about 1 %. 

In Chinese traditional medicine, this crude drug has been used firom ancient times as a cough cure, and as an antipyretic and diaphoretic. On the other hand, the subterranean parts of Ephedra plants are used to stop sweating, as this medicine possesses a contradictory action to the above-ground parts of the same plant. 

Kitani Y, Zhu S, Omote T, Tanaka K, Batkhuu J, Sanchir C, Fushimi H, Mikage M, Komatsu K (2009) Molecular analysis and chemical evaluation of Ephedra plants in Mongolia. Biol Pharm Bull 32 1235-1243... 

O Dowd NA, McCauley PG, Richardson DHS, Wilson G (1993) Callus production, suspension culture and in vitro alkaloied of Ephedra.. Plant Cell Tissue Organ Cult 34 149-155... 

Rh2(5-DOSP)4 as catalyst and the presence of a chiral auxiliary bound to the diazoacetate derivatives, trans-2,3-dihydrobenzofurans have been prepared in good yields and high diastereoselectivities. This efficient method has been applied to the total syntheses of the complex macrocyclic spermine alkaloid (—)-ephedradine A (orantine) 32, an ypo-tensive component of the crude Chinese drug mao-kon prepared from the roots of Ephedra plants and the penta-cyclic indole alkaloid (—)-serotobenine 33 extracted from Rhaphidophara decursiva ... 

Ephedrine contains two chiral centres giving rise to four possible stereoisomers, with ephedrine and pseudoephedrine being dominant in the Ephedra plant. Ephedrine itself, (Fig. 18.5) is identifiable as the (lR,2S)-stereoisomer and... 

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