The cancer-fighting compound, known as glucosinolates, undergoes a series of chemical reactions that activates enzymes involved in the detoxification of cancer-causing molecules.
In addition, one of the anti-carcinogens produced, allyl isothiocyanate (AITC) demonstrated 90% absorption when ingested.
Horseradish’s pungent flavour is primarily caused by the AITC. This compound is produced from the hydrolysis of sinigrin by the enzyme myrosinase.
One study found that sinigrin accounts for about 80-90% of total glucosinolate (GS) content in horseradish roots and leaves.
The team from the University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES) wanted to investigate the AITC formation from several horseradish types.
In addition, the study also set out to evaluate the potential cancer-prevention properties of horseradish roots and antioxidant activity.
In total, 11 horseradish strains were selected for this study and compared in quantity and activity.
They were then given a rating of either US Fancy No. 1, or US No. 2 based on diameter and length of the root.
The US Fancy and US No. 1 are major available grades in the market. However, there is no information on whether the US Department of Agriculture (USDA) grade horseradish root not only on food quality, but also with cancer chemopreventive activity.
The team found that the higher-grade US Fancy horseradishes had significantly more glucosinolates than US No. 1.
Concentrations of various glucosinolate hydrolysis products also differed according to USDA grade, with US Fancy having greater AITC and US No. 1 having greater 1-cyano 2,3-epithiopropane (CETP), another by product of sinigrin.
“We knew horseradish had health benefits, but in this study we were able to link it to the activation of certain detoxifying enzymes for the first time,” says University of Illinois crop scientist Mosbah Kushad.
“There was no information on whether the USDA grade of the horseradish root is associated with cancer preventive activity, so we wanted to test that,” he added.
Studies into the cancer-fighting properties of horseradish have revealed the depth of its complex compound make-up.
A recent paper reported that sulphate supply was closely related with glucosinolate (GS) accumulation in horseradish.
Here, the study attributed the different GS concentration between US Midwest horseradish and Nordic horseradish to the different weather and/or soil conditions as well as genetic backgrounds.
In a similar vein, the researchers in the current study suggested the reduced variation in AITC may be related to its volatility.
Researchers found the average AITC concentration from the six US Fancy grade horseradish root extracts was 42.4 micromoles (μmol) per grams dry weight and ranged from 37.4 to 47.1 μmol/g dry weight.
Horseradish root diameter (grade) was another source of variation in AITC and CETP concentrations. In general, AITC levels fell and CETP levels rose in the lower root grades including US No. 1 and US No. 2, compared to the corresponding levels in US Fancy grade roots.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, DOI: 10.1021/jf505591z
“Correlation of Quinone Reductase Activity and Allyl Isothiocyanate Formation Among Different Genotypes and Grades of Horseradish Roots.”
Authors: K.M. Ku, E. Jeffery, J. Juvik and M. Kushad