glucosinolates

Glucosinolates are a family of sulfur- and nitrogen-containing glycosides found mainly in the Brassicaceae. They consist of a β-D-glucopyranose residue linked to a sulfur-containing aglycone that bears a variable side chain derived from amino acids. Based on their side chains, glucosinolates are typically classified as aliphatic, aromatic, or indolic.

In intact plant tissue, glucosinolates are stable until damaged. The enzyme myrosinase (a thioglucoside glucohydrolase) releases glucose and an unstable aglycone that rearranges to hydrolysis products such as isothiocyanates, nitriles, or thiocyanates.

The nature of the hydrolysis products depends on pH and the presence of specifier proteins; isothiocyanates like sulforaphane and phenethyl isothiocyanate are common, while nitriles can form under certain conditions.

Glucosinolates function in plant defense against herbivores and pathogens and contribute to the characteristic pungent flavors of many cruciferous vegetables, including mustard, horseradish, broccoli, and cabbage.

In human nutrition, glucosinolate-derived compounds are studied for potential cancer-preventive effects. Cooking can inactivate plant myrosinase, shifting hydrolysis to gut microbes; content varies with cultivar, growth conditions, harvest maturity, and storage.