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(also mustard oils or isothiocyanate esters), organic compounds having the general formula R—N=C=S, where R is an aliphatic or aromatic radical. Liquids with a pungent odor, they can be distilled without decomposition, are insoluble in water, are lacrimators, and cause burns upon contact with skin. Table 1 gives the properties of some isothiocyanates.

Table 1. Properties of some isothiocyanates
IsothiocyanateBoiling point,
Density, g/cm3
Methyl isothiocyanate  
CH3NCS ......................1191.069 (37°)
Ethyl isothiocyanate  
C2H5NCS ..................1311.003 (18°)
Allyl isothiocyanate  
CH2=CH–CH2NCS ............1501.016 (15°)
Phenyl isothiocyanate  
C6H5NCS .................2221.129 (23°)

Many isothiocyanates are found in plants either in the free state or in the form of glucosides—compounds with sugars or other substances. Allyl isothiocyanate is the pungent and odoriferous component of mustard. Isothiocyanates are quite reactive; they readily add to the N=C bond alcohols, phenols, mercap-tans, and other compounds to give thiocarbamic acid derivatives (R—NH—CX=S, where X = OR, OAr, SH, SR, CN, NH2, and so forth). Addition of carboxylic and thiocarboxylic acids is accompanied by liberation of COS and CS2, respectively, with the formation of acid amides (R—NH—COR’)- Isothiocyanates are hydrolyzed on heating (particularly readily in the presence of acids or alkalies) and are reduced by nascent hydrogen to amines (RNH2); they undergo halogenation with the formation of aminocarbonyl dihalides (R—N=CX2) and react with mercuric oxide, forming isocyanates (R—N=C=O). Isothiocyanates are obtained by thermal isomerization of thiocyanates (R—S—C=N), by decomposition of the derivatives of dithio-carbamic acid or of thiourea, and by other methods.

Many isothiocyanates have bactericidal, fungicidal, and insecticidal properties. Some of them are used, for example, in the production of synthetic fibers.


References in periodicals archive ?
Scientists from JIC and the University of Edinburgh found that bacterial pathogens carrying the sax genes, thought to be involved in detoxification and removal of isothiocyanates, were able to overcome these defences.
New biomarkers for monitoring the levels of isothiocyanates in humans.
Isothiocyanates are potent contact allergens that occur naturally in vegetables.
Isothiocyanates, which occur in cruciferous vegetables as their glucosinolate conjugates and released upon chewing the vegetables, are broad-spectrum inhibitors of metabolic activation of several nitrosamines including the tobacco-specific nitrosamines (NNK) and N'nitrosornicotine (NNN).
A recent study published in the Journal of Medicinal Chemistry sheds light on how isothiocyanates in cauliflower exert their anti-cancer activity.
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Isothiocyanates (ITCs) derived from cruciferous vegetables induce apoptosis in cancer cells.
Cabbage is packed with phytonutrients, including glucosinolates, which convert to cancer-blocking compounds like sulphoraphane and isothiocyanates (ITC's), plus flavonoids like quercetin.
By not eating his broccoli, President Bush missed out on indole 3-carbinol, isothiocyanates and sulforaphane--all phytochemicals in cruciferous vegetables.
broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.