Alkaloids 3 Flashcards
Amaryllidaceae family includes…….
snowdrop
daffodil
snowflake
All these species are common in _______________.
Galanthus spp (snowdrop), Narcissus spp (daffodil) and Leucojum spp (snowflake). All these species are common in Europe.
Galantamine, lycorine and related alkaloids are biosynthesized from …….
phenylalanine and tyrosine
Lycorine and many of the other compounds are…………..
benzylisoquinoline alkaloids
Galantamine is benzylisoquinoline alkaloids True or False?
False
galantamine is different (azepine).
Galantamine was originally isolated from …………in early 1950’s
Galanthus woronowii
Galantamine isolated in 1950s was shown to inhibit …….
acetylcholinesterase
State how Galantamine was marketed?
originally in control of anaesthesis to antagonise ________ such as ___________ and derivatives. The use then spread to other fields of medicine.
It has been marketed as a hydrochloride salt (Nivalin®) since 1958; originally in control of anaesthesis to antagonise muscle relaxants such as curare and derivatives. The use then spread to other fields of medicine.
Use of Galantamine from 1980s
It was shown to penetrate the blood-brain barrier and enhance cognitive function in Alzheimer’s patients. It has dual action; is a reversible inhibitor of acetylcholinesterase and as well influences nicotinic receptors via an allosteric site which results in the release of acetylcholine.
Note: It does not provide a cure but slows down the reduction of cognitive function.
Used for mild to moderate dementia associated with Alzheimer’s.
Available as tablets and modified release tablets.
Galantamine is commercially isolated from…….
Leucojum and Galanthus spp
Galantamine is also synthesized and marketed as …..
Reminyl®.
Lycorine has antifungal action. True or False?
True
Psilocybin & Psilocin are structurally related. True or False?
TRUE
Psilocybin & Psilocinare structurally related and are often termed as…..
‘psychedelics’.
Facts about Psilocybin and it conversion in the body
Psilocybin occurs in a number of Psilocybe specie
(called magic mushrooms) and is converted to psilocin in the body after ingestion.
Facts about Psilocybin and LSD(lysergic acid diethylamide)
Both psilocybin and LSD interact with ________________ and this decreases activity in some parts of the brain, especially the _____________ which is considered to be about the sense of oneself and introspective thought. Hence, the brain becomes less sensitive to _____________.
Both psilocybin and LSD interact with serotonin receptors and this decreases activity in some parts of the brain, especially the default mode network (DMN) which is considered to be about the sense of oneself and introspective thought. Hence, the brain becomes less sensitive to negative thoughts.
More recently, …………….. is being considered as a possible therapeutic drug for psychiatric, depression, and anxiety.
Psilocybin
State the use of Psilocybin in cancer patients
use it in cancer patients to help reduce anxiety and depression
List the side effects of Psilocybin
5
increase in blood pressure, heart rate, and headaches, with a few subjects reporting fear and anxiety.
Ergot Indole Alkaloids are biosynthesized from?
tryptophan.
Ergot alkaloids’ are so named because…..
they are obtained from the fungus ‘Ergot’ (Claviceps purpurea).
What is Ergot?
Ergot is the _____________ stage of the fungus _____________ growing on the rye ________.
Ergot is the sclerotium stage of the fungus Claviceps purpurea growing on the rye Secale cereale.
list the number of indole alkaloids with interesting pharmacological applications known 6
physostigmine, psilocin, reserpine, vinblastine.
Synthetic derivatives based on 5 hydroxytryptamin include sumatriptan and zolmitriptan.
What is the consequence of ergot being a parasite of cultivated plants (cereal crops)?
is that it gets consumed widely from time to time. The ergot may be collected with the grain and if consumed, will cause the disease ‘ergotism’.
what are the symptoms of ergotism?
One symptom of ergotism is the burning sensation and occurrence of gangrene in the body extremities. This results from eating contaminated grain over a long time. Some of the biologically active compounds have a vasoconstriction action on the blood vessels. Other symptoms include hallucinations, epileptic fits, and convulsions.
The midwives in the 16th century are known to have collected the ergot and used it to promote childbirth. True or False?
True
Different alkaloids have been isolated from ergot. These can be divided into whether they are based on what and what?
lysergic acid or iso-lysergic acid
The pharmacologically active alkaloids isolated from ergot are based on……….
The pharmacologically active ones are based on (+)-lysergic acid.
The alkaloids can also be divided into those that are water-soluble (___%) and water-insoluble (_______ %). true/false
The alkaloids can also be divided into those that are water-soluble (20 %) and water-insoluble (80 %).
List an example of a water-soluble alkaloid and its structure
has a _________ side chain bonded to the C-8 _________ group
Ergometrine (isomer = ergometrinine) – has a 2-amino-propan-1-ol side chain bonded to the C-8 carboxylic acid group
State the clinical features of Ergometrine
Clinical features: Produces an ___________ and contraction of the __________, and is used as the ___________ as an intramuscular injection after childbirth for prevention and treatment of _________. Also formulated with _________; together more effective in early pregnancy haemorrhage.
Clinical features: Produces an oxytocic effect and contraction of the blood vessels, and is used as the maleate salt as an intramuscular injection after childbirth for prevention and treatment of haemorrhage. Also formulated with oxytocin; together more effective in early pregnancy haemorrhage.
List an example of a water-insoluble alkaloid
Water-insoluble alkaloids (peptide derivatives)
________ is based on lysergic acid amide, which is coupled to ___________, ____________, and ________.
Water-insoluble alkaloids (peptide derivatives)
Ergotamine – is based on lysergic acid amide, which is coupled to proline, phenylalanine, and alanine.
State the clinical features of Ergotamine
Acts as an agonist on _________ and _______ receptors; produces __________ – used in the treatment of _________as the tartrate salt
Clinical features: Acts as an agonist on 5-HT and α–adrenergic receptors; produces peripheral vasoconstriction – used in the treatment of migraine attacks as the tartrate salt
Bromocryptine is an example of a semi-synthetic derivative of Ergot indole alkaloid used for…..
maybe used to treat _____________ more useful for reducing the release of prolactin due to a tumor and thus___________; also used to treat __________; some use for the treatment of __________
maybe used to treat Parkinsonism (dopamine agonist); more useful for reducing the release of prolactin due to a tumor and thus reduce lactation; also used to treat ACROMEGALY; some use for the treatment of breast cancer.
Pergolide and Cabergoline are semi-synthetic derivatives indicated for……
__________ and ____________ (latter also has a similar action to ___________ , but has a longer duration of action) - used to treat __________ (adjunct to __________).
Pergolide and Cabergoline (latter also has a similar action to bromocryptine, but has a longer duration of action) - used to treat Parkinsonism (adjunct to co-beneldopa).
What is the therapeutic use of Methysergide?
Methysergide – _______________, used as a prophylactic to treat severe cases of ________ and ___________. Not recommended as a _________due to side effects. However, triptans (e.g. sumatriptan), which are also serotonin ________, modeled on ________, have replaced METHYSERGIDE.
Methysergide – 5-HT antagonist, used as a prophylactic to treat severe cases of migraine and cluster headaches. Not recommended as a first-line treatment due to side effects. However, triptans (e.g. sumatriptan), which are also serotonin agonists, modeled on lysergic acid, have replaced methysergide.
What is the therapeutic indication of Lysergic acid diethylamide (LSD-25)?
Lysergic acid diethylamide (LSD-25) – powerful hallucinogenic drug that can lead to severe psychotic states; abused considerably and as little as 50 μg is needed for producing an effect.
List examples of therapeutically important alkaloids
Ephedrine, castanospermine, nicotine , arecoline , tubocurarine , colchicine emetine , reserpine , vinblastine and vincristine , strychnine , physostigmine and pilocarpine, and quinine .
Ephedrine (decongestant), castanospermine (AIDS virus), nicotine (antismoking), arecoline (vermicide), tubocurarine (muscle relaxant), colchicine (gout), emetine (amoebic dysentery), reserpine (antihypertensive), vinblastine and vincristine (anticancer), strychnine (appetite stimulant), physostigmine and pilocarpine (miotic), and quinine (malaria).
