EPHEDRINE: NATURAL SOURCE:
The herb má huáng ( Ephedra sinica), used in traditional Chinese medicine (TCM), contains ephedrine and pseudoephedrine as its principal active constituents. This Chinese herb ma-huang, known in the est as ephedra, is the dried stem o! three species species o! primitive shrubs in the ephedra ephedra !amil" !ound !ound in desert regions regions around the world. world. Three Three spec species ies are comm common onl" l" used used as sour source ce plan plants ts## E. sini sinica ca,, E. inter interme medi dia, a, and and E. e$uisetina, all native to the steppes o! north and northwestern China. %amil"# Ephedraceae
STRUCTURE:
SYNTHESIS:
Ephedrine can be s"nthesi&ed !rom ben&aldeh"de in a !ew di!!erent wa"s. 'ccording to the !irst, ben&aldeh"de is condensed with nitroethane, giving -meth"l--nitro--phen"lethanol, which is reduced to -meth"l--amino--phen"lethanol. The necessar" *-isomer is isolated !rom the mi+ture o! isomers b" cr"stalli&ation. Meth"lation o! this gives ephedrine.
The second method consists o! the !ermentation o! glucose b" "east carboligase in the presence o! ben&aldeh"de, which during the process turns into phen"lacet"lcarbinol. This is reduced b" h"drogen in the presence o! meth"lamine to give the desired ephedrine.
MEDICINAL USES: •
ts chemical properties raise blood pressure and heart rate and open up the large air passages in the lungs..This compounds stimulate the brain, increase heart rate, constrict blood vessels (increasing blood pressure), and e+pand bronchial tubes (making breathing easier).
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t is also used !or allergies and ha" !ever nasal congestion and respirator" tract conditions such as bronchospasm, asthma, and bronchitis.
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Ephedrine has also been used as a weight loss product and b" athletes who believe it makes them stronger or have more energ" and endurance. t is used as a weight-loss aid, sometimes in combination with aspirin and ca!!eine.
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t is used to increase urine !low in people who retain !luids.
PROPERTIES:
Ephedrine was !ound to be ver" soluble in water, alcohol, and chloro!orm and nearl" insoluble in petroleum ether upon cooling. eing a strong base, ephedrine displaces ammonia !rom its salts. /olutions o! the salts in water var"ing !rom to 0 percent were !ound to be e+ceedingl" stable. 1o change in strength occurred a!ter 2 months storage at room temperature. The solutions are $uite sable at boiling temperature. ts speci!ic rotation varied with the di!!erent solvents used. Ephedrine h"drochloride has a melting point o! 34533 6C.7 STRUCTURE ACTIVITY RELATIONSHIP: •
(-)Ephedrine, (8) Ephedrine, (-) psi ephedrine and (8) psi ephedrine inhibit both the neuronal and e+traneuronal uptakes o! noradrenaline in isolated
9abbit heart. (-) ephedrine is the most active isomer !or the inhibition o! both neuronal and e+traneuronal uptakes. •
's it acts on -adrenergic receptor Ma+imal alpha- and beta-adrenergic receptor activit" depends on the presence o! h"dro+"l groups on the : and ; carbons o! the ben&ene ring.
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'mine
group
two
carbons
awa"
!rom
an
aromatic
group
!or
s"mpathomimetic activit". •
! the amine is primar" or secondar" it will have direct action, but i! the amine is tertiar" it will have poor direct action.
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'lso i! the amine has bulk" substituents then it will have greater eta adrenergic receptor activit", but it the substituent is non-bulk" then it will !avor the alpha adrenergic receptors.
