Hygrine Hygrine, molecular formula C 8 H 15 NO, is found mainly in coca
leaves (Erythroxylum coca). It is a thick yellow oil, having a pungent taste
and odour.
Cuscohygrine Cuscohygrine, molecular formula C 13 H 24 N 2 O, is a dimeric
pyrrolidine alkaloid found in coca, and also in many species of the
Solanaceae. It is an oil, but soluble in water.
Tropane alkaloids
These are the group of alkaloids that possess a 8-methyl-8-aza-bicyclo
[1,2,3]octane or tropane skeleton, e.g. atropine, cocaine and scopolamine.
Tropane alkaloids occur mainly in plants from the families Solanaceae and
Erythroxylaceae. 8-Aza-bicyclo[1,2,3]octane, i.e. tropane without the 8methyl group, is known as nortropane.
N
R
N Me
O
O
OH
N Me
O
O
O
OMe
1
2
3
4
5
6
7
8
Tropane R = Me
Nortropane R = H
Atropine
Cocaine
Atropine Atropine, molecular formula C 17 H 23 NO 3 , is a tropane alkaloid, first isolated from the ‘deadly nightshade’ (Atropa belladonna), and
also found in many other plants of the Solanaceae. Atropine is a racemic
mixture of D-hyoscyamine and L-hyoscyamine. However, most of the
pharmacological properties of atropine are due to its L-isomer, and due to
its binding to muscarinic acetylcholine receptors. Atropine is a competitive antagonist of the muscarinic acetylcholine receptors. The main
medicinal use of atropine is as an opthalmic drug. Usually a salt of
atropine, e.g. atropine sulphate, is used in pharmaceutical preparations.
Atropine is used as an acycloplegic to paralyse accommodation temporarily, and as a mydriatic to dilate the pupils. It is contraindicated in
patients predisposed to narrow angle glaucoma. Injections of atropine are
used in the treatment of bradycardia (an extremely low heart-rate),
asystole and pulseless electrical activity (PEA) in cardiac arrest. It is
also used as an antidote for poisoning by organophosphate insecticides
and nerve gases.
The major adverse effects of atropine include ventricular fibrillation,
tachycardia, nausea, blurred vision, loss of balance and photophobia. It also
6.2 ALKALOIDS
293
leaves (Erythroxylum coca). It is a thick yellow oil, having a pungent taste
and odour.
Cuscohygrine Cuscohygrine, molecular formula C 13 H 24 N 2 O, is a dimeric
pyrrolidine alkaloid found in coca, and also in many species of the
Solanaceae. It is an oil, but soluble in water.
Tropane alkaloids
These are the group of alkaloids that possess a 8-methyl-8-aza-bicyclo
[1,2,3]octane or tropane skeleton, e.g. atropine, cocaine and scopolamine.
Tropane alkaloids occur mainly in plants from the families Solanaceae and
Erythroxylaceae. 8-Aza-bicyclo[1,2,3]octane, i.e. tropane without the 8methyl group, is known as nortropane.
N
R
N Me
O
O
OH
N Me
O
O
O
OMe
1
2
3
4
5
6
7
8
Tropane R = Me
Nortropane R = H
Atropine
Cocaine
Atropine Atropine, molecular formula C 17 H 23 NO 3 , is a tropane alkaloid, first isolated from the ‘deadly nightshade’ (Atropa belladonna), and
also found in many other plants of the Solanaceae. Atropine is a racemic
mixture of D-hyoscyamine and L-hyoscyamine. However, most of the
pharmacological properties of atropine are due to its L-isomer, and due to
its binding to muscarinic acetylcholine receptors. Atropine is a competitive antagonist of the muscarinic acetylcholine receptors. The main
medicinal use of atropine is as an opthalmic drug. Usually a salt of
atropine, e.g. atropine sulphate, is used in pharmaceutical preparations.
Atropine is used as an acycloplegic to paralyse accommodation temporarily, and as a mydriatic to dilate the pupils. It is contraindicated in
patients predisposed to narrow angle glaucoma. Injections of atropine are
used in the treatment of bradycardia (an extremely low heart-rate),
asystole and pulseless electrical activity (PEA) in cardiac arrest. It is
also used as an antidote for poisoning by organophosphate insecticides
and nerve gases.
The major adverse effects of atropine include ventricular fibrillation,
tachycardia, nausea, blurred vision, loss of balance and photophobia. It also
6.2 ALKALOIDS
293