Chemistry
Amygdalin is extracted from almond or apricot kernel cake by boiling in ethanol; on evaporation of the solution and the addition of diethyl ether, amygdalin is precipitated as white minute crystals. Liebig and Wöhler were already able to find three decomposition products of the newly discovered amygdalin: sugar, benzaldehyde, and prussic acid (hydrogen cyanide). Later research showed that sulfuric acid decomposes it into -glucose, benzaldehyde, and prussic acid; while hydrochloric acid gives mandelic acid, -glucose, and ammonia.
Several glucosidase enzymes are known to act on amygdalin, leading to its decomposition by various pathways. Maltase causes partial degradation, giving -glucose and mandelic nitrile glucoside, C6H5CH(CN)O·C6H11O5. Emulsin, on the other hand, decomposes it into benzaldehyde, cyanide, and two molecules of glucose; this enzyme occurs in the bitter almond, and consequently the seeds invariably contain free cyanide and benzaldehyde. An "amorphous amygdalin" is said to occur in the cherry laurel (Prunus laurocerasus). Lastly, amygdalin beta-glucosidase and prunasin beta-glucosidase consecutively catalyze loss of the two glucose units to yield mandelonitrile, which can then decompose to form free cyanide and benzaldehyde.
Natural amygdalin has the R configuration at the chiral benzyl center. Under mild basic conditions, this stereogenic center epimerizes; the S epimer is called neoamygdalin.
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