sinigrin

Sinigrin is a glucosinolate, specifically an allyl (2-propenyl) glucosinolate, widely distributed in the Brassicaceae family. It is especially abundant in black mustard (Brassica nigra) seeds and white mustard (Sinapis alba), where it contributes to the characteristic pungency of mustard preparations. As a natural precursor, sinigrin is the glucosinolate form that yields allyl isothiocyanate (AITC) upon enzymatic hydrolysis.

Chemically, sinigrin consists of a glucose moiety linked to a sulfur-containing aglycone with an allyl side chain derived from the amino acid methionine. The glucosinolate biosynthetic pathway in plants assembles this side chain before attaching it to the glucose-containing core structure.

When plant tissue is damaged, the enzyme myrosinase comes into contact with sinigrin and hydrolyzes it to glucose and a destabilized aglycone, which rearranges to allyl isothiocyanate. Depending on environmental conditions, myrosinase activity can also produce other products such as nitriles or thiocyanates. AITC is the compound primarily responsible for the sharp aroma and pungency associated with mustard and related condiments.

In culinary and industrial contexts, sinigrin and its hydrolysis products contribute to flavor and have been studied for antimicrobial and potential health effects. Research on glucosinolates, including sinigrin, explores possible roles in cancer prevention and thyroid-related effects, but findings are mixed, and high intake of glucosinolates may affect iodine uptake in sensitive individuals. Analytically, sinigrin serves as a reference glucosinolate in phytochemical analyses and is commonly quantified after hydrolysis.