Page 94 - Phytochemistry 2 (06-PG 605)

Dimeric Vinca Alkaloids (Vindoline + Catharanthin Units)

Vinblastine and vincristine
These are dimeric alkaloids having indole and dihydro-indole
nuclei. They differ in the presence of N-methyl group in vinblastine
and N-formyl group in vincristine. They have closely related
structures.

N

N
H3COOC

N

H3CO N HO OCOCH3
COOCH3
R = CHO R
Vincristine R = CH3
Vinblastine

Tests for identification
1. Vanillin /HCl reagent gives with:

- Vinblastine a pink colour
- Vincristine an orange-yellow colour
2. Para-dimethylaminobenzaldehyde (PDAB) reagent (Van-Urk's
reagent): gives vinca alkaloids in presence glacial acetic acid and
concentrated H2SO4 a reddish-brown colour.
Uses
 Vinblastine is used for treatment of Hodgkin's disease and
carcinoma resistant to other therapy.
 Vincristine has a cytotoxic effect. It is used in treatment of
leukemia in children.

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