Cyanogenic glycosides, including amygdalin from bitter almonds, release hydrocyanic acid upon hydrolysis, contributing to their medicinal properties. Bitter almonds, distinct from sweet almonds, contain amygdalin and are cultivated in various regions including Italy and Spain. The oil from bitter almonds is used in skin lotions, while their consumption is limited due to their toxic properties.

1. CYANOGENIC GLYCOSIDES
BITTER ALMOND

2. • INTRODUCTION :
• They are also called as cyanophore glycosides, because of the
presence of hydrocyanic acid (HCN) as aglycone moiety.
• These are the glycosides which on hydrolysis yields hydrocynic
acid (HCN), benzaldehyde and sugars.
• The medicinal activity of cyanogenetic glycosides is due to
presence of hydrocyanic acid.
• These are the characteristics of family Rosaceae.
• For examples Amygdalin obtained from bitter almond (Prunus
amygdalus), Prunasin obtained from wild cherry bark.

3. BITTER ALMOND
• Biological source :
• It consists of dried ripe seeds of Prunus amygdalus var amara
• Family : Rosaceae
• Geographical source :
• Bitter almonds trees are native of Iran and Asia
• At present they are widely cultivated in Sicily, Italy, Spain,
Portugal, France and Morocco.
• Bitter almonds tress can not be easily distinguished from sweet
almond trees (Prunus communis).

4. • Description
• Colour: Brown
• Odour: No specific odour
• Taste: Bitter
• Shape : flattened, oblong
• Surface : markings on testa
• Size : 20 mm long, 12.5 mm wide and 8 mm thick.
• In form and appearance bitter almonds are usually smaller and
less regular.
• They have a bitter taste and easily distinguished from that of the
sweet almond by its characteristic odour.

5. Chemical constituents
• Bitter almond contain fixed oil (40 to 45%) and proteins.
• Enzyme emulsin.
• It contains colorless, crystalline glucoside – Amygdalin (2.5 to 4%).
• Amygdalin on hydrolysis due to presence emulsin in presence of water
decompose into benzaldehyde and hydrocyanic acid.
• This change is effected by the emulsin contained in all the tissues of bitter
almond.
• It contains 0.5 % of volatile oil.
• Sweet almonds do not contain amygdalin and hence they are not bitter
in taste.
• Almond oil consist of a mixture of glycerides of oleic, linoleic, palmitic,
myristic, palmitoleic, margaric, stearic, linolenic, arachidic, gadoleic,
behenic and cruic acid.
• The unsaponifiable matter contains beta sitosterol, avenasterol,
cholesterol, brassica sterol and tocopherols.

6. Chemical test :
• Grignard Reaction Test:
• Liberation of hydrocyanic acid on hydrolysis, changes sodium
picrate (yellow colour) into sodium purpurate (brick-red colour).
• Procedure :
• First of all, dip a strip of white filter paper into a solution of picric
acid (1 % w/v in water) drain and then dip into a solution of
sodium carbonate (10% w/v in water) and drain. Now, place the
crushed and moistened drug material in a small flask, and
subsequently suspend the strip of the prepared sodium picrate
paper above the material and stopper the flask with an air tight
cork. Maintain the flask in a warm place for 1 hour when the
liberated HCN would turn the sodium picrate paper from its
original yellow colour to brick red colour due to the formation of
sodium isopurpurate (Grignard’s Reaction).

7. • Uses :
• Hydrocyanic acid is very poisonous and makes the drug
unsuitable for internal administration.
• Bitter almonds are used as sedative due to hydrocyanic acid
content.
• Oil is used in skin lotion as demulcent and emollient.
• Sweet almond oil is used as flavoring agent in food products but
bitter almond oil should not be used as flavoring of foods.