Prunasin 2 -glucoside

The main cyanogenic glycoside in laurel is prunasin, the P-o-glucoside of benzaldehyde cyanohydrin. The enzymic hydrolysis of prunasin may be visualized as an acid-catalysed process, first of all hydrolysing the acetal linkage to produce glucose and the cyanohydrin. Further hydrolysis results in reversal of cyanohydrin formation, giving HCN and benzaldehyde. 

Bitter almonds contain amygdalin, which is the P-D-glucoside of prunasin, so it hydrolyses sequentially to the same products. Cassava, which is used in many parts of the world as a food plant, contains linamarin, which is the P-D-glucoside of acetone cyanohydrin. Preparation of the starchy tuberous roots of cassava for food involves prolonged hydrolysis and boiling to release and drive off the HCN before they are suitable for consumption. 

Salicin is an (9-glycoside of a phenol, namely salicyl alcohol. Salicin is a natural antipyretic and analgesic found in willow bark, and is the template from which aspirin (acetylsalicylic acid, see Box 7.13) was developed. Prunasin from cherry laurel is an example of a cyanogenic glycoside, hydrolysis of which leads to release of toxic HCN (see Box 7.7). It is the (9-glucoside of the alcohol mandelonitrile, the trivial name for the cyanohydrin of benzaldehyde. It is the further hydrolysis of mandelonitrile that liberates HCN. 

Nahrstedt, A., Jensen, P.S. and Wray, V. (1989) Prunasin-6 -malonate, a cyanogenic glucoside from Merremia dissecta. Phytochemistry, 28, 623. ... 

Wild cherry is a large tree, native to southern Canada. It is widespread in the United States and Europe. The bark, small branches, and twigs are used to prepare the fluid extract and tincture. The main constituent of wild cherry extract is the glucoside prunasin, which on enzymatic hydrolysis yields prussic acid, glucose, and benzaldehyde. Also present are coumarin, phytosterols, benzoic acid, and fatty acids (e.g., oleic, linoleic, and palmitic acids). It has a characteristic sweet, tart, cherry-like flavor. Wild cherry bark extract is commonly used at concentrations of approximately 50-800 ppm in foods and pharmaceuticals. 

Sambunigrin (D-mandelonitrile glucoside) from the leaves of the elder tree—Sambucus nigra (Caprifoliaceae)—is isomeric to prunasin. 

The bitter taste sometimes occurring in stewed sour cherries, plums and other stone fruits of the Rosaceae family is caused by the presence of cyanogenic glycosides, especially prunasin (see Section 10.3.2.3.1). Rowan berries, the fruit of rowan Sorbus aucuparia), which are used to make jam or jelly with a distinctive bitter taste, contain 3-hydroxy-5-hexanolide -D-glucoside (8-224). Enzymatic... 

Bark contains condensed tannins, prunasin (d-mandelonitrile glucoside) emulsin eudesmic acid (3,4,5-trimethoxybenzoic acid) /i-couma-ric acid scopoletin sugars andothers (karrer). Fruit skin contains capulin anthocyanins. Prunasin is a cyanogenic glucoside that is hydrolyzed by the enzyme prunase into hydrocyanic acid (HCN, prussic acid). 

Bennett, W.D. Isolation of the Cyanogenetic Glucoside Prunasin from Bracken Fern. Phytochem. 7, 151 (1968). 

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