Structure–Activity Relationship Study on Isothiocyanates: Comparison of TRPA1-Activating Ability between Allyl Isothiocyanate and Specific Flavor Components of Wasabi, Horseradish, and White Mustard

Allyl
isothiocyanate (ITC) (4) is the main pungent component
in wasabi, and it generates an acrid sensation by activating TRPA1.
The flavor and pungency of ITCs vary depending on the compound. However,
the differences in activity to activate TRPA1 between ITCs are not
known except for a few compounds. To investigate the effect of carbon
chain length and substituents of ITCs, the TRPA1-activiting ability
of 16 ITCs was measured. Since most of the ITCs showed nearly equal
TRPA1-activiting potency, the ITC moiety is likely the predominant
contributor to their TRPA1-activating abilities, and contributions
of other functional groups to their activities to activate TRPA1 are
comparatively small.