Isoquinoline alkaloids

Question 1

What are isoquinoline alkaloids?

Answer 1

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.

Question 2

Which plants are isolquinoline alkaloids found in?

Answer 2

They are found in papaveraceae, berberidaceae and ranunculaceae families and show remarkable biological properties.

Question 3

How are they synthesized?

Answer 3

They are derivates of tyrosine or phenylalanine. They are synthesized from the condensation of phenylethylamine derivates with phenylacetaldehyde drivates.

Question 4

What is the classification of isoquinoline alkaloids?

Answer 4

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)

Question 5

What is opium?

Answer 5

Opium is the dried latex obtained from the unripe capsules of Papaver somniferum.

Question 6

Which family does opium belong to?

Answer 6

Papaveraceae

Question 7

How is opium produced?

Answer 7

It is produced by drawing longitudinal incisions into the unripe capsules of P. soniferum and collecting the dried latex.

Question 8

Which are the active constituents of opium?

Answer 8

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%)

Question 9

What is the extraction process of morphine?

Answer 9

1. The opium powder is shaken with Calcium chlroide salt and filtered.
2. The filtrate is concentrated with 10% w/v solution of NaOH to solubilize morphine and codeine.
3. Filtrate is extracted with chloroform containing solvent
   4.Morphine is extracted as the upper aqueous layer contains morphine and bottom layer contains codeine.
4. Aqueous layer is first acidified and subsequently alkalized and morphine is extracted as white crystals

Question 10

What are the characteristics of morphine?

Answer 10

White colorless crystals, bitter tase and odorless

Question 11

Uses of morphine

Answer 11

analgesic
respiratory, emetic and cough center suppressant
hypnotic and sedative effect
produces euphoria and subject to abuse

Question 12

What is codeine?

Answer 12

Codeine is an ether of morphine. It is also known as methylmorphine

Question 13

How is codeine produced?

Answer 13

It is produced either by methylation of morphine or by demethylation of thebaine

Question 14

What are macroscopic characteristics of papaverine

Answer 14

White crystalline, bitter taste, odorless

Question 15

Uses of codeine

Answer 15

narcotic analgesic
anti-tussive agent
less potential for abuse than morphine

Question 16

Papaverine

Answer 16

It is found in opium and can be synthetically produced

Question 17

Use of papaverine

Answer 17

used as for vasospam and visceral spasms (anti-spasmodic drug)

Question 18

Noscapine

Answer 18

also known as narcotine, not a narcotic, exists as a free base in opium
used as anti-tussive

Question 19

Thebaine

Answer 19

it is used to reverse opioid poisoning and to quit addiction
It is a biosynthetic intermediate of morphine pathway

Question 20

What is Ipecac?

Answer 20

Ipecac is the dried rhizome and root of Caephalis Ipecachuana from family Rubiaceae

Question 21

Biosynthesis

Answer 21

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.

Question 22

Major alkaloids of ipecac

Answer 22

Caephalin, emetin and psychotrine

Question 23

Use of ipecac

Answer 23

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.

Question 24

Emetin extraction

Answer 24

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.

Question 25

Caephalin

Answer 25

Isoquinoline alkaloid obtained from Caephalin Ipecachuana.
Used to induce vomiting.

Question 26

Psychotrin

Answer 26

Yellow colored crystalline alkaloid found in ipecac. which has effective properties against HIV-reverse transcriptase