4. Alkaloidal amines Flashcards
What are some alkaloidal amines?
- Ephedrine (in Ephedra distachya)
- colchicine [in seeds, corms of Autumn crocus (Colchicum autumnale) ]
- canthinone in Khat Plant (Catha edulis)
- mescaline [in Peyote cactus (Lophophora williamsii) ]
Explain the biosynthesis of colchicine?
- Phenylalanine→ Cinnamic acid→ p-coumaric acid→ ferulic acid
- Tyrosine→ Tyramine→ Tyrosol
- Tyrosol + p-coumaric acid → p-coumaroyltyramine
- p-coumaroyltyramine (hydroxylation, methylation and rearrangement reactions) →colchicine
What is the alkaloidal conc. of colchium plant?
Colchicum contains the alkaloids colchicine up to 0.8% in seed and 0.6% in corm.
Give physical characteristics of colchicine?
Colchicine occurs as pale yellow, amorphous scales or powder that turns yellow on exposure to light. It is soluble in water and ether and is freely soluble in alcohol and chloroform.
Give the solubility of colchicine?
Contains one amido nitrogen and do not form well defined series of salts as do other alkaloids but is precipitated by many alkaloidal reagents so are considered alkaloids.
Give the actions and uses of colchicine?
It reduces lactic acid production by leukocytes which in turn decrease uric acid in addition there is reduction in phagocytosis which decreases inflammatory response.
Colchicine doubles the chromosome number and is used to make new varieties of plants and to treat neoplastic diseases in animals at experimental level.
Give the dose of colchicine?
Prophylactic dose is 500-650ug,1-3 times daily and intravenously 0.5-1 mg, 1-2 times daily.
Explain the biosynthesis of ephedrine?
Formed either by extraction of plant material, orreduction condensation chemical reaction between L-1-phenyl-1acetylcabinol and methylamine. This yields L-Ephedrine free from D-isomer.
How is the carbinol precursor for ephedrine produced?
The carbinol precursor in the reaction is produced biosynthetically by fermentive action of brewer’s yeast on benzaldehyde. Reaction involves the dismutation of pyruvic acid to lactic acid and acetyl Co-A which in turn condenses with benzaldehyde to yield L-1-phenyl-1acetylcabinol.
Give the characteristics of ephedrine?
Ephedrine occurs as white, rosette or needle crystals or as an unctuous mass. Soluble in organic solvents. The solution is turbid if ephedrine is not dry. It melts at 30-40’C depending on its water content.
What are the uses of ephedrine?
Ephedrine is a potent sympathomimetic drug that stimulates alpha, beta 1 , beta 2 adrenergic receptors. It excites sympathetic system, causes vasoconstriction and cardiac stimulation and produces similar effects to those of epinephrine. It produces a rather lasting rise in blood pressure causes mydriasis and diminishes hyperemia.
What are the salts of ephedrine?
Ephedrine sulfate, Ephedrine HCl
Give the characteristics of ephedrine sulfate?
Occurs as fine, white odourless crystals or as powder and darkens when exposed to light.
What are the uses of ephedrine sulfate?
It is used to combat extensive hypotensive states and for allergic disorders such as bronchial asthma as well as local treatment of nasal decongestion.
What dose of ephedrine sulfate is used?
25-50mg, 6-8 times daily for oral/parenteral use.
0.1-0.15 ml of 1-3% solution 2-3 times a day for external use.
