Glycosidation cyanogenic

Like other glycosides, cyanogenic glycosides are cleaved to a carbohydrate and an alcohol on hydrolysis. 

An example of important non-volatile nitriles is 4-hydroxybenzyl cyanide, which is found in mustard pastes made from white mustard seeds Leucosinapis album) containing glucosinolate sinalbin. Nonvolatile nitriles also include cyanogenic glycosides, cyanogenic lipids and amino acids that contain the cyano group. 

Plant toxins which affect contractions of the heart muscle or metabolic respiration processes are associated with acute poisoning in mammals. Two groups of glycosides (cyanogenic glycosides and cardiac glycosides) are present in plants commonly available to grazing animals and are responsible for livestock losses. 

The cyanogenic glycosides, phaseolunatin [554-35-8], C qH yNO, and vicianin [155-57-7], C2C)H25N02q, have been isolated from lima beans and vetch, respectively. Several studies have reported that heating (cooking) acts to decrease the quantity of HCN Hberated by these compounds upon enzymatic hydrolysis. 

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. 

Fig. 2.13 Generalized reaction sequence from starting amino acid [65] to product cyanogenic glycoside [66]...

L. corniculatus in southern England, and demonstrated that presence of cyanogenic glycosides is dominant over their absence. Further work on inheritance of cyano-genesis in this species was complicated by the fact that this clover is a tetraploid. Work with other species led to more definitive results, however. 

Fig. 2.14 Generalized pattern of distribution of cyanogenic glycosides in Europe...

A few paragraphs above, we saw the part played by Lotus corniculatus in the cyanogenic glycoside story. We now turn onr attention to another aspect of this species that has attracted a considerable amonnt of attention and has, coincidentally. 

The authors suggest that altitudinal variation in phytochemical constituents remains unknown. That this is factually incorrect is revealed by the well-known work on the effect of elevation on cyanogenic glycosides, as shown in the case of the clovers above, as well as in the case of alkaloid variation in Berberis just described. 

Fig. 6.2 Compounds 519-524, cyanogenic glycosides from Passiflora species...

---