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Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

II) Terpenoid Bitter Principles

a) Monoterpenes

1) Cantharidin:
O O
COOH
-H 2 O
O O O O O
COOH
O O
Cantharidic acid Cantharidin
Cantharidin

▪ It is obtained from cantharides “Spanish flies”, Cantharis vesicatoria, family Meloidae.

▪ It is the inner anhydride of the dicarboxylic acid “cantharidic acid”.
▪ Optically inactive.

▪ Insoluble in cold water, soluble in the organic solvents.

Preparation:

• The acidified (dil. HCl) powdered insect suspension is extracted using ethyl acetate.

• The ethyl acetate extract containing cantharidin and fats is evaporated, and fats are removed by

petrol ether in which cantharidin is slightly soluble.
• The crude cantharidin is crystallized from hot alcohol.

Chemical test:

▪ To a crystal of cantharidin, add drop of dilute formaldehyde and few drops of concentrated
sulfuric acid. A brown to black color is developed.

Uses:

a) Topical:
1) Removal of warts.

2) Hair preparations

b) Internal: False popular reputation as aphrodisiac; It is dangerous and may result in priapism

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