Alkaloids

Question 1

Unsaturated pyrrolizidine alkaloids are known to be toxic. What herbs are known to contain these alkaloids, and in what organ is the toxicity observed?

Answer 1

Symphytum officinale

Hepatotoxicity

Question 2

List some plant families known to be rich sources of alkaloids

Answer 2

Solanaceae
Papaveraceae
Liliaceae
Piperaceae

Question 3

What can you generalise about the phytochemical class of alkaloids?

Answer 3

Non protein secondary plant metabolite containing protein

All end in “-ine”

Broad range of action depending on type, but commonly exert either depressant (morphine) or stimulant (caffeine) effect on nervous system

Question 4

What class of alkaloid does atropine belong to, and what is it’s major action?

Answer 4

Tropane alkaloid (eg in Atropa belladonna)

Anticholinergic (blocks action of acetylcholine, a neurotransmitter that transfers signals between cells to affect body functions)
- drying mucus membranes, reducing sweating, secretions and salivation, dilating pupils, impair memory

Question 5

Describe the chemistry and pharmacology of Corydalis ambigua. What is the name of the major alkaloid present in the herb?

Answer 5

Over 20 alkaloids isolated
Sedative, anti-addictive, analgesic potency up to 10-40% of opium

Alkaloid herb, actions on CNS, alkaloids absorb readily and easily across blood brain barrier

L-tetrahydrodalmatine (THP) most potent; dopamine antagonist - helps interrupt chemical process of addiction.

Question 6

Cautions and contraindications of Hydrastis canadensis

Answer 6

Pregnancy, lactation, jaundiced neonates.

Kidney disease, babies with glucose-6-phosphate dehydrogenase deficiency

May inhibit absorption of cyclocsporine in renal transplant patients