Glucosinolates structure

Sorensen, H. (1990) Glucosinolates structure, properties and function, in Canola and Rapeseed Production, Chemistry, Nutrition and Processing Technology (ed. R. Shahidi). Van Nostrand Reinhold, New York, pp. 149-72. 

R272 N. Agerbirk and C. E. Olsen, Glucosinolate Structures in Evolution , Phytochemistry, (Elsevier), [online computer file], 2012, 77, 16. 

Fig. 6 Glucosinolate structure and metabolism, and side chains (R) occurring in common cruciferous...

Glucosinolate structure Trivial name Corresponding isothiocyanate (R-N=C=S) Example crop plants... 

Figure 8.7 Basic glucosinolate structure (a) and commonly consumed glucosinolates and their respective isothiocyanates (b). ITC, Isothiocyanate.

Figure 13.1 Degradation of glucosinolates. Hydrolysis is catalyzed by myrosinases and gives rise to different degradation products dependent on the structure of the glucosinolate side chain and the hydrolysis conditions. (I) isothiocyanates, the major product at pH >7 (II) nitriles, the major product at pH <4 (ID) thiocyanates, produced from 2-propenyl-, benzyl-, and 4-methylthiobutylglucosinolates (IV) oxazolidine-2-thiones, produced from glucosinolates with P-hydroxylated side chains, (V) epithionitriles, produced in the presence of epithiospecifier proteins.

One current estimate of NP diversity totals ryo.ooo different structures, yet this huge chemical diversity is generated from only a few biochemical pathways that branch from the metabolism shared by most organisms. About 60% of the known NP diversity comes from one ancient pathway (the isoprenoids or terpenoids), another 30% comes from some other ancient pathways related to each other (the polyphenols, phenylpropanoids or polyketides) and less than 10% of NPs (alkaloids) comes from a more diverse family of pathways. There seems to be a rough correlation between the number of species possessing one pathway and the total diversity of NPs made by that route. Consequently, the minor groups of NPs that comprise less than 1% of the total NP diversity (e.g., the glucosinolates) tend to be restricted to a small number of species. 

Isothiocyanates are sulphur- and nitrogen-containing phytochemicals with the general formula R-NSC, e.g. phenylethyl isothiocyanate 199, 3-phenylpropyl isothiocyanate 200 and benzyl isothiocyanate 201 (Structure 4.58). Isothiocyanates occur naturally as glucosinolate conjugates mainly in cruciferous vegetables. Isothiocyanates are also responsible for the typical flavour of these vegetables [1-4,21-23, 25, 54]. 

The myrosinase-glucosinolate system occurs in 16 plant families.17 It is likely that this system evolved from the ancient (and near ubiquitous) cyanogenic glycosides. This hypothesis is supported by the similarity, in sequence and structure, of glucosinolate biosynthetic enzymes and the hydrolytic enzymes (myrosinase or p-glucosidase).18 The biochemistry of these metabolites also indicates a convincing evolutionary relationship.19 Furthermore, on the basis of robust phylogenetic trees,... 

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