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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Composition and Methods Development Laboratory » Research » Publications at this Location » Publication #320479
Title: Myrosinase-dependent and –independent formation and control of isothiocyanate products of glucosinolate hydrolysis

Author
item ANGELINO, DONATO - University Of Illinois
item DOSZ, EDWARD - University Of Illinois
item Sun, Jianghao
item HOEFLINGER, JENNIFER - University Of Illinois
item VAN TASSELL, MAXWELL - University Of Illinois
item Chen, Pei
item Harnly, James - Jim
item MILLER, MICHAEL - University Of Illinois
item JEFFERY, ELIZABETH - University Of Illinois

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2015
Publication Date: 10/6/2015
Citation: Angelino, D., Dosz,.B., Sun, J., Hoeflinger, J.L., Van Tassell, M.L., Chen, P., Harnly, J.M., Miller, M.J., Jeffery, E.H. 2015. Myrosinase-dependent and –independent formation and control of isothiocyanate products of glucosinolate hydrolysis. Frontiers in Plant Science. doi: 10.3389/fpls.2015.00831.

Interpretive Summary: Brassica plants include many popular vegetables, such as mustards, cabbage, and raddishes. They contain a enzyme called myrosinase that hydrolyzes glucosinolates to form toxic isothiocyanates, as a defense against bacteria, fungi, insects and herbivores including man. However, low levels of isothiocyanates are beneficial to human as they trigger a host defense system in mammals that protects them against chronic diseases. Because humans typically cook their brassica vegetables, destroying myrosinase, there is a great interest in determining how human microbiota can hydrolyze glucosinolates and release them to provide the health benefits of isothiocyanates. Isothiocyanates are highly reactive electrophiles, binding reversibly to thiols (sulfur-copntaining compounds), but accumulate and cause damage when free thiols are not available. We found that addition of excess thiols released protein-thiol-bound isothiocyanates, but that the microbiome supports only poor hydrolysis unless exposed to dietary glucosinolates for a period of days. These findings explain why 3 – 5 servings a week of brassica vegetables may provide health effects, even if they are cooked.

Technical Abstract: Brassicales contain a myrosinase enzyme that hydrolyzes glucosinolates to form toxic isothiocyanates, as a defense against bacteria, fungi, insects and herbivores including man. Low levels of isothiocyanates trigger a host defense system in mammals that protects them against chronic diseases. Because humans typically cook their brassica vegetables, destroying myrosinase, there is a great interest in determining how human microbiota can hydrolyze glucosinolates and release them, to provide the health benefits of isothiocyanates. Isothiocyanates are highly reactive electrophiles, binding reversibly to thiols, but accumulating and causing damage when free thiols are not available. We found that addition of excess thiols released protein-thiol-bound isothiocyanates, but that the microbiome supports only poor hydrolysis unless exposed to dietary glucosinolates for a period of days. These findings explain why 3 – 5 servings a week of brassica vegetables may provide health effects, even if they are cooked.