ARS | Publication request: GLUCOSINOLATE HYDROLYSIS PRODUCTS FROM VARIOUS PLANT SOURCES: PH EFFECTS, ISOLATION, AND PURIFICATION

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 25, 2004
Publication Date: March 21, 2005
Citation: Vaughn, S.F., Berhow, M.A. 2005. Glucosinolate hydrolysis products from various plant sources: pH effects, isolation, and purification. Industrial Crops and Products. 21:193-202.

Interpretive Summary: Glucosinolates are a group of plant chemicals that are found in twelve plant families, including the mustard family. Glucosinolates can be broken down either by enzymes or chemically to produce compounds called isothiocyanates and nitriles. Some of these isothiocyanates and nitriles are of interest to synthetic chemists as precursors to make other chemicals, while some are of interest to scientists studying their biological activities. However, many of these compounds are unavailable in purified form, or if they are available, are extremely expensive. In the current study we have developed methods to produce bulk quantities of these isothiocyanates and nitriles using commercially-available seeds as the source of parent glucosinolates. These methods permit the production of relatively large amounts of these compounds without the need for laborious and expensive chemical separation equipment, saving time and money.

Technical Abstract: Glucosinolates are a class of organic anions which may be hydrolyzed either enzymatically via the enzyme myrosinase or non-enzymatically to form primarily isothiocyanates and/or nitriles. The isolation and purification of these hydrolysis products are of particular interest both for their potential use in organic synthesis and for scientific studies concerning their biological activities. Methods were developed for the isolation and purification of gram-scale amounts of several omega-(methylthio)alkyl-, omega-(methylsulfinyl)alkyl-, omega-(methylsulfonyl)alkyl- and substituted benzyl glucosinolate hydrolysis products, the isothiocyanates erucin [1-isothiocyanato-4-(methylthio)butane], iberin [1-isothiocyanato-3-(methylsulfinyl)propane], cheirolin [1-isothiocyanato-3-(methylsulfonyl)propane], lesquerellin [1-isothiocyanato-6-(methylthio)hexane], hesperin [1-isothiocyanato-6-(methylsulfinyl)hexane], sulforaphene [1-isothiocyanato-4-(methylsulfinyl)but-3-ene], 3-methoxybenzyl isothiocyanate and 4-hydroxybenzyl isothiocyanate, and the nitriles iberverin nitrile [1-cyano-3-(methylthio)propane], erucin nitrile [1-cyano-4-(methylthio)butane], and 3-methoxybenzyl nitrile using defatted seedmeal from several different genera within the crucifer family (Brassicaceae) and meadowfoam family (Limnanthaceae) as the source of parent glucosinolates. The procedures use solvent extraction of autolyzed defatted seedmeals together with variable reaction pHs and solvent partitioning to obtain relatively pure (generally >97%) compounds without necessitating chromatographic separation.