Isoquinoline alkaloids Flashcards
What are isoquinoline alkaloids?
Isoquinoline alkaloids are heterocyclic, aromatic organic compounds. They are isomers of quinoline. They are benzopyridines which means they comprise of benzene ring fused with pyridine ring.
Which plants are isolquinoline alkaloids found in?
They are found in papaveraceae, berberidaceae and ranunculaceae families and show remarkable biological properties.
How are they synthesized?
They are derivates of tyrosine or phenylalanine. They are synthesized from the condensation of phenylethylamine derivates with phenylacetaldehyde drivates.
What is the classification of isoquinoline alkaloids?
Classified into 3 groups:
1. Benzyl-isoquinoline alkaloids (e.g. Opium)
2. Tetrahydro-isoquinoline alkaloids (e.g Ipecac)
3. Phenithyl isoquinoline alkaloids (e.g Colchicine)
What is opium?
Opium is the dried latex obtained from the unripe capsules of Papaver somniferum.
Which family does opium belong to?
Papaveraceae
How is opium produced?
It is produced by drawing longitudinal incisions into the unripe capsules of P. soniferum and collecting the dried latex.
Which are the active constituents of opium?
It contains more than 30 alkaloids, most of which are combined with organic acid, meconic acid. Major alkaloids are:
1. Morphine (8-12%)
2. Codeine (0.8-2.5%)
3. Noscapine (4-8%)
4. Papaverine (0.5-2.5%)
5. Thebaine (0.5-2%)
What is the extraction process of morphine?
- The opium powder is shaken with Calcium chlroide salt and filtered.
- The filtrate is concentrated with 10% w/v solution of NaOH to solubilize morphine and codeine.
- Filtrate is extracted with chloroform containing solvent
4.Morphine is extracted as the upper aqueous layer contains morphine and bottom layer contains codeine. - Aqueous layer is first acidified and subsequently alkalized and morphine is extracted as white crystals
What are the characteristics of morphine?
White colorless crystals, bitter tase and odorless
Uses of morphine
analgesic
respiratory, emetic and cough center suppressant
hypnotic and sedative effect
produces euphoria and subject to abuse
What is codeine?
Codeine is an ether of morphine. It is also known as methylmorphine
How is codeine produced?
It is produced either by methylation of morphine or by demethylation of thebaine
What are macroscopic characteristics of papaverine
White crystalline, bitter taste, odorless
Uses of codeine
narcotic analgesic
anti-tussive agent
less potential for abuse than morphine
Papaverine
It is found in opium and can be synthetically produced
Use of papaverine
used as for vasospam and visceral spasms (anti-spasmodic drug)
Noscapine
also known as narcotine, not a narcotic, exists as a free base in opium
used as anti-tussive
Thebaine
it is used to reverse opioid poisoning and to quit addiction
It is a biosynthetic intermediate of morphine pathway
What is Ipecac?
Ipecac is the dried rhizome and root of Caephalis Ipecachuana from family Rubiaceae
Biosynthesis
The biosynthesis starts when dopamine molecule is condensed with a secologanin molecule, which is deglucosylated and a glycone proemetin is produced.
It is then condensed with a second molecule of dopamine to produce caephalin and emetin.
Major alkaloids of ipecac
Caephalin, emetin and psychotrine
Use of ipecac
It is used to induce vomiting in case of drug overdose or poisoning. It irritates the gastric mucosa and triggers the chemoreceptor center in the brain.
Emetin extraction
Obtain the dried root, crush and make a powder. Then dissolve it with a solvent like ethanol or water.
The solvent is concentrated to increase emetin dissolution
The process may require purification and crystallization to obtain purified emetin.
Caephalin
Isoquinoline alkaloid obtained from Caephalin Ipecachuana.
Used to induce vomiting.
Psychotrin
Yellow colored crystalline alkaloid found in ipecac. which has effective properties against HIV-reverse transcriptase
