CYANOGENIC GLYCOSIDES

(Cyanophore or cyanogenetic glycosides)

These glycosides upon hydrolysis yield HCN. They mostly present in plants of family Rosaceae, Euphorbiaceae, Leguminosae.

Most commonly occurring glycoside is amygdalin from bitter Almonds.

Test: -

HCN evolves over a period of 30min. This changes the colour of paper from yellow to Brick red due to conversion of sod-picroate to sod-isopurpurate. Hydrolysis will be more rapid if we add few drops of H₂SO₄.

Wild Cherry

B.O. Prunus seotina

Family Rosaceae

P.U. Dried (stem) bark

Habitat: -

Plants are indigenous to Eastern United States and Canada. Plants are tall attaining a height of 30m.

Collection: -

The bark is collected in autumn, at which time it is most active carefully dried in sun and kept in airtight container. The colour of bark is short and granular and the colour of fractured surface is reddish Grey. The drug is almost odourless but after moistening with water it evolves a strong odour of bitter almonds i.e. odour of benzaldehyde. Taste of drug is astringent, bitter resembling to that of bitter almonds.

Constituents: -

Active constituents are prunacin, which is formed by partial hydrolysis amygdalin. It is accompanied by enzyme prunase, benzoic acid, trimethyl gallic acid and traces of volatile oil.

Uses: -

Wild cherry possesses tonic, sedative and expectorant properties. It is also used as flavouring agent.

Lactone Glycosides

Cantharide (Animal source). Beatles

Z.O. Cantharis vesicatoria

Family Meloidae

P.U. Dried insects

These are found on certain shrubs or trees of the families caprifoliaceae and oleaceae. These plants are found in central and southern Europe.

Collection: -

These insects are collected in June and July particularly in morning when they are inactive or sluggish plants are shaken with sticks and insects are collected on cloths spreading on the ground. The insects are killed by exposing them to the fumes of carbon disulphide, acetic acid, chloroform or ammonia. Finally the dried insects are stored in airtight containers and few drops of carbon tetrachloride or chloroform are added as a preservative.

Constituents: -

Contheridine 0.1-0.6% is the active constituent, other constituents are fat 12%, fixed oil, uric acid, formic acid and acetic acid.

Uses: -

Counter-irritant

Vesicant.

Rubifacient.

Now a day it is less commonly used.