Page 105 - phytochemistry II -pharmD general
P. 105
These complex ester alkaloids are the physiologically active medicinally
valuable alkaloids of Veratrum. They are applied as hypotensive agents, and are
often used in combination with Rauwolfia alkaloids.
They are used in the form of pure alkaloidal salts e.g. protoveratrine A&B or purified
alkaloidal extracts or even in the form of the crude drug (rhizomes or roots).
Other classes of alkaloids
The versatility of alkaloids structures embrace a wide range of heterocyclic
structures; some of these were unknown to chemists, before their discovery in
natural alkaloids.
The following are just examples of these unusual heterocyclic ring structures,
that are chosen because representative alkaloids are of either medicinal,
toxicological or commercial values.
1. Pyrrolizidine alkaloids H OH
HO
N
Pyrrolizidine
Pyrrolizidine alkaloids are a group of naturally occurring alkaloids of which
there are over 300 known examples. They are found very frequently in plants of
the family Leguminosae (mainly the genus Crotalaria), and in the family
Compositae (mainly the genus Senecio)
2. Quinolizidine alkaloids
N
Quinolizidine
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