Glucosinolates

The glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. These natural chemicals most likely contribute to plant defence against pests and diseases, but are also enjoyed in small amounts by humans and are believed to contribute to the health promoting properties of cruciferous vegetables.

Glucosinolates constitute a natural class of organic compounds that contain sulfur and nitrogen and are derived from glucose and an amino acid. They are water-soluble anions and can be leached into the water during cooking. Glucosinolates belong to the glucosides. Every glucosinolate contains a central carbon atom, which is bound via a sulfur atom to the thioglucose group and via a nitrogen atom to a sulfate group (making a sulfated aldoxime). In addition, the central carbon is bound to a side group; different glucosinolates have different side groups, and it is variation in the side group that is responsible for the variation in the biological activities of these plant compounds. Some glucosinolates:

Glucosinolates occur as secondary metabolites of almost all plants of the order Brassicales (e.g. families Brassicaceae = Cruciferae, Capparidaceae, and Caricaceae), but also in the genus Drypetes (family Putranjivaceae). For example, glucosinolates occur in cabbages (white cabbage, Chinese cabbage, broccoli), watercress, horseradish, capers and radishes. They are typically in parts consumed, with the pungent taste of these vegetables due to breakdown products (isothiocyanates or mustard oils) of glucosinolates. The glucosinolates are also found in the seeds of these plants.

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