Alkaloids are nitrogen-containing organic compounds produced by plants and animals that have pharmacological effects. The document discusses the biosynthesis of several classes of alkaloids including those derived from ornithine, lysine, phenylalanine, tyrosine, tryptophan, and lysergic acid. Key intermediates include ornithine, tropine, dopamine, and tryptamine, which contribute carbon and nitrogen atoms to various alkaloid structures like piperidine rings in lysine derivatives or indole rings in tryptophan derivatives. Morphine, codeine, and other opium alkaloids are derived from tyrosine, while quinine is derived from tryptophan and terpenoid

1. BIOSYNTHESIS OF
ALKALOIDS
Ornithine derivatives, Tropane biosynthesis, Lysine derivatives,
Phenylalanine derivatives, Tyrosine derivatives, morphine
biosynthesis, Tryptophan derivatives, Quinoline derivatives,
Lysergic acid biosynthesis
SUBMITTED TO
MADAM NAZIA ASLAM

2. DEFINITION
An alkaloid is a nitrogenous organic molecule that has a pharmacological effect on
humans and animals. They are a class od compounds which typically contain nitrogen
and have complex ring structures. Alkaloids are found as secondary metabolites in
plants (e.g., Vinca and Datura), animals (e.g., in shellfish), fungi and can be extracted
from their sources by treatment with acids (usually hydrochloric acid or sulphuric
acid) though organic acids such as maleic acid and citric acid.

3. ORNITHINE DERIVATIVES
• In plants it is formed mainly from L-glutamate.
• Ornithine supplies a C4N building block to the alkaloid, principally as a five
membered pyrrolidine ring system, but also as a part of the tropane alkaloids.
• Derivatives such as;
• Tobacco (nicotine, nornicotine)
• Solanaceae family

5. BIOSYNTHESIS OF TROPANE
• The starting compound of this synthesis is ornithine and methylornithine is the first
intermediate.
• Ornithine Tropine
• Phenylalanine Tropic acid
• Tropine + Tropic acid l – Hysocyamine/Atropine

7. LYSINE DERIVATIVES
• L-Lysine is the homologue of L-ornithine, and it too functions as an alkaloid
precursor, using pathways analogous to those noted for ornithine.
• Lysine supplies a C5N building block to the alkaloid, principally as a six-membered
piperidine ring system.
• Derivatives such as;
• lupine, lupinine, lupanine, anabasine, pelletierine alkaloids
• Lycopodium, a substance obtained from Lycopodium spp.

8. PHENYLALANINE DERIVATIVES
• L-phenylalanine is less frequently utilized, and usually it contributes only carbon
atoms, e.g., C6C3, C6C2, C6C1 units without providing a nitrogen atom from its amino
group.
• Ephedrine, the main alkaloid in species of Ephedra (Ephedraceae) is a prime
example.

10. TYROSINE DERIVATIVES
• The first essential intermediate is dopamine; dopamine is the precursor in the
biosynthesis of papaverine, berberine and morphine.
• L-phenylalanine is also the precursor of the formation of ephedrine.

11. BIOSYNTHESIS OF MORPHINE
• A range of similar compounds like the opium alkaloids, thebaine codeine etc. are
derived during the formation of morphine.
• Tyrosine is the precursor of morphine – a potent analgesic.
• Tyrosine is the precursor of codeine – a anti-tussive

13. BIOSYNTHESIS OF TRYPTOPHAN
DERIVATIVES
• The tryptophan derivatives corresponds to 25% of all known alkaloids and many of
them are medicinally valuable.
• Tryptophan and its decarboxylated product (tryptamine) are precurosrs fro the
biosynthesis of broad range of indole alkaloids of which the vinca and rauwolfia
alkaloids are examples and also in the alkaloids belonging to the families like
Apocynaceae, Loganiaceae and Rubiaceae.

15. BIOSYNTHESIS OF QUINOLINE ALKALOIDS
• Some of the most remarkable examples of terpenoid indole alkaloid modifications
are to be found in the genus Cinchona (Rubiaceae), in the alkaloids quinine,
quinidine, cinchonidine and cinchonine for their antimalarial properties.

17. BIOSYNTHESIS OF LYSERGIC ACID
DERIVATIVES
• The building blocks for lysergic acid are tryptophan (less the carboxyl group) and
isoprene unit.
• Alkylation of tryptophan with dimethylallyl diphosphate gives 4-dimethylallyl-L-
tryptophan, which then undergoes N-methylation. Formation of tetracyclic ring
sytem of lysergic acid is known to proceed through chanoclavine-I and agroclavine.