Page 20 - Phytochemistry 2 (06-PG 605)

Classification of alkaloids

Alkaloids have been classified according to the following:

1- Biogenetic classification:

• (biosynthetic pathway of production in the plant)

• Phenyl alanine (phenylalkylamine alkaloids)

• Tyrosine (Opium alkaloids)

• Ornithine (Tropane alkaloids)

• Tryptophan (Indole & Quinoline alkaloids )

2- The taxonomical origin classification:

In many cases different alkaloids obtained from the same plant have similar
chemical structure, e.g.Coca alkaloids, Atropa alkaloids, Rauwolfia alkaloids, ergot
alkaloids and so on.

3-The pharmacological action classification: e.g.CNS stimulant alkaloids; caffeine

4- Classification as amines: Classification as 1ry, 2ry, 3ry ,4ry alkaloids

5- Chemical classification:

Classification according to the nature of the basic chemical structure from which
they are derived.

According to chemical structure, two broad divisions may be recognized:

• A- Non-heterocyclic or atypical alkaloids that are called “protoalkaloids” or
biological amines.

• B- Heterocyclic or typical alkaloids, that are sub-classified into different
groups according to their ring structure.

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