Amygdala Amara, B.P., Bitter Almond.
Bitter almonds are the ripe dried seeds of Prunus Amygdalus, Stokes, var. amara, Baillon (N.O. Rosaceae). They are also official in the U.S.P. Almond trees, both sweet and bitter, are widely cultivated in the countries that border on the Mediterranean. The fruit is a drupe, which splits open as it ripens, disclosing the hard endocarp, within which the almond is to be found. Bitter almonds are exported chiefly from Morocco and Sicily. The seeds are shorter and broader than the ordinary Jordan sweet almond, being about 2 centimetres long and 1.25 centimetres broad, and are at once distinguishable by the characteristic odour evolved when they are triturated with water, as well as by their bitter taste.
Constituents.—The chief constituents of bitter almonds are fixed oil (about 50 per cent.), the bitter crystalline glucoside amygdalin (about 3 to 4 per cent.), and at least two enzyme ferments, emulsin and laccase, together with other proteins. The fixed oil, obtained by crushing and pressing the seeds, constitutes the bulk of the genuine almond oil of commerce. When the cake thus produced is mixed with warm water and allowed to stand, the ferment emulsin splits up the glucoside amygdalin into dextrose, hydrocyanic acid, and benzaldehyde. If steam be then passed through the mixture, the hydrocyanic acid and benzaldehyde distil over, partly in the free state, but mainly in unstable combination as benzaldehyde-cyanhydrin. These form a heavy oil (essential oil of almonds) which sinks in water. Bitter almonds yield about 0.5 to 0.8 per cent. of essential oil, which may contain from 4 to 7 per cent. of hydrocyanic acid.
Action and Uses.—The action of bitter almonds depends upon the hydrocyanic acid they yield. Unpleasant symptoms, especially in children, may arise from eating relatively small quantities. For administration in cough mixtures, Pulvis Amygdalae Amarae Compositus is prepared, bitter almonds being used instead of the sweet variety in the B.P. formula; from the compound powder the corresponding Mistura Amygdalae Amarae is prepared. For toilet purposes, and as a basis of lotions, Mistura Amygdalae Amarae is preferred without gum acacia and sugar.
- Mistura Amygdalae Amarae, B.P.C.—BITTER ALMOND MIXTURE. 3 in 40.
- Used as a basis for soothing skin lotions, especially to allay the smarting of sunburn.
- Mistura Amygdalae Amarae Composita, B.P.C.—COMPOUND BITTER ALMOND MIXTURE. 1 (compound bitter almond powder) in 8.
- Contains a variable amount of hydrocyanic acid and is given for coughs. Dose.—15 to 30 mils (½ to 1 fluid ounce).
- Pulvis Amygdalae Amarae Compositus, B.P.C.—COMPOUND BITTER ALMOND POWDER.
- Bitter almonds, 10; refined sugar, 5; gum acacia, 1.