Cyanide cyanogenic glycosides

Cyanogenic glycosides are potentially toxic because they liberate hydrogen cyanide on enzyme-catalyzed or acidic hydrolysis. Give a mechanistic explanation for this behavior for the specific cases of... 

Naturally occurring compounds called cyanogenic glycosides, such as lotau-stralin, release hydrogen cyanide, HCN, when treated with aqueous acid. The reaction occurs by hydrolysis of the acetal linkage to form a cyanohydrin, which then expels HCN and gives a carbonyl compound-fa) Show the mechanism of the acetal hydrolysis and the structure of the cyanohydrin that results. 

Nonvolatile Inhibitors. Glycosides A number of toxic constituents are known to be released by the enzymatic degradation of various glycosides. Some of the volatile components have been mentioned previously—i.e., isothiocyanates from mustard oil glycosides and hydrogen cyanide from cyanogenic glycosides. 

Cyanogenic glycosides toygdalin (or its reduced form, prunasin) and dhurrin are known to be allelopathic (3,48). Not only are these glycosides hydrolyzed to produce hydrogen cyanide, but the benzaldehyde or hydroxybenzaldehyde (produced during hydrolysis) is oxidized to benzoic acid which itself nay be toxic to several species (3, 48). 

Linamurin is the principal cyanogenic glycoside in cassava its toxicity is due to hydrolysis by intestinal microflora releasing free cyanide (Padmaja and Panikkar 1989). Rabbits (Oryctolagus cuniculus) fed 1.43 mg linamurin/kg BW daily (10 mg/kg BW weekly) for 24 weeks showed effects similar to those of rabbits fed 0.3 mg KCN/kg BW weekly. Specihc effects produced by linamurin and KCN included elevated lactic acid in heart, brain, and liver reduced glycogen in liver and brain and marked depletion in brain phospholipids (Padmaja and Panikkar 1989). 

Effects of cyanide on wildlife and range animals that graze foliage with high cyanogenic glycoside content (Towill et al. 1978)... 

Over 2,650 plant species can produce hydrogen cyanide (Seigler 1991 Swain et al. 1992). These include edible plants such as almonds, pits from stone fruits (e.g., apricots, peaches, plums, cherries), sorghum, cassava, soybeans, spinach, lima beans, sweet potatoes, maize, millet, sugarcane, and bamboo shoots (Fiksel et al. 1981). The cyanogenic glycoside content of a foodstuff is usually expressed as the amount of cyanide released by acid hydrolysis glycoside concentrations are rarely reported (WHO 1992). 

Seigler DS. 1991. Cyanide and cyanogenic glycosides. In Rosenthal GA, Berenbaum MR, eds. Herbivores their interaction with secondary plant metabolites. Academic Press, New York, N.Y. 35-77. 

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