Decomposition Products of Allyl Isothiocyanate in Aqueous Solutions

Pecháček, Radomír; Velı́šek, J.; Hrabcová, Helena

doi:10.1021/jf970316z

Cited by 90 publications

(65 citation statements)

References 11 publications

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“…[25,77,81,82] In contrast to such cases in which the major degradation product was primarily the corresponding amine, neither 63 or 64 were detected in our reactions (see Table 2). Rather, isothiocyanates appeared simply to diminish over time, without explanation as to the factors responsible for this behavior or the final state of the isothiocyanates.…”

Section: Aqueous Degradation Of Isothiocyanatescontrasting

confidence: 70%

Identification, Synthesis, and Enzymology of Non‐natural Glucosinolate Chemopreventive Candidates

et al. 2008

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Isothiocyanates (ITCs) are one of the many classes of breakdown products of glucosinolates found in crucifers such as broccoli and are thought to be partially responsible for the reduced risk of degenerative diseases associated with the consumption of vegetables. The production of ITCs such as L-sulforaphane is dependent on the hydrolytic bioactivities of myrosinase, localized both within vegetable tissues and within flora of the human GI tract, and is associated with important cancer chemopreventive activities. We hypothesized that novel isothiocyanates with enhanced chemopreventive properties relative to L-sulforaphane could be identified and that their glucosinolate precursors could be synthesized. From a library of 30 synthetic ITCs, we identified several with bioactivities equal or superior to those of L-sulforaphane. The corresponding non-natural glucosinolate precursors to these novel ITCs were constructed and found to be substrates for myrosinase. By utilizing a novel RP-HPLC assay to monitor myrosinase-dependent hydrolysis reactions, 2,2-diphenylethyl glucosinolate and (biphenyl-2-yl)methyl glucosinolate were shown to exhibit 26.5 and 2.8 %, respectively, of the relative activity of sinigrin and produced their corresponding ITCs in varying yields. These data support the notion that non-natural glucosinolates can act as prodrugs for novel ITCs, with a mechanism of action reliant on their hydrolytic cleavage by myrosinase. Such non-natural glucosinolates may serve as very economical chemopreventive agents for individuals at risk for cancers of and around the GI tract.

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Section: Aqueous Degradation Of Isothiocyanatescontrasting

confidence: 70%

Identification, Synthesis, and Enzymology of Non‐natural Glucosinolate Chemopreventive Candidates

et al. 2008

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“…Dismutation of this compound leads to DAS and diallyl polysulfides. Similar mechanisms are also proposed in aqueous AITC solutions [27].…”

Section: Sinigrin Decompositionsupporting

confidence: 70%

Decomposition of sinigrin by methanol/ammonia/water treatment in model systems and mustard (Brassica nigra L.) seed meal

Pecháček

Velı́šek

Davı́dek

2000

Eur Food Res Technol

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Sinigrin (allylglucosinolate) was stored at 20 7C, 40 7C, and 60 7C in solutions containing 10% ammonia in 95% methanol (CH 3 OH/NH 3 /H 2 O). The individual samples were analyzed for their contents of sinigrin, its decomposition product allyl isothiocyanate (AITC) and other reaction products. The major reaction products were allyl thiourea, methyl ester of Nallyl thiocarbamoyl acid and allyl cyanide. A newly identified decomposition product of sinigrin was ethylcyanide. Defatted Brassica nigra seed meal was treated by the CH 3 OH/NH 3 /H 2 O mixture to simulate the procedure used for rape and mustard seed meal detoxification. Suspensions of the meal in the above mixture of solvents were heated at 20 7C, 40 7C and 60 7C, respectively. The major reaction products were the same as those arising from sinigrin. Minor products identified were 4-hydroxybenzyl isothiocyanate formed from sinalbin and 2-hydroxy-butenyl cyanide which arises from progoitrin. In all cases, AITC was very rapidly decomposed. Mechanisms explaining sinigrin decomposition are presented and discussed.

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“…Measurements of myrosinase activity MYR activity was quantitatively determined on both the free and immobilized enzyme according to the pH-Stat method (Palmieri et al 1987). As reported by Croft (1979) and Tookey et al (1980), 1 mol of GL hydrolyzes to yield 1 equivalent of hydrogen sulphate ion (pK A =2), which at the pH values of plant cells and soils looses 1 H + giving a sulphate ion.…”

Section: Purification Of Glucosinolatesmentioning

confidence: 99%

Activity of myrosinase from Sinapis alba seeds immobilized into Ca-polygalacturonate as a simplified model of soil-root interface mucigel

et al. 2010

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Ca-polygalacturonate is a demethoxylated component of pectins which are constitutive of plant root mucigel. In order to define the role of root mucigel in myrosinase immobilization and activity at root level, a myrosinase enzyme which had been isolated from Sinapis alba seeds was immobilized into Capolygalacturonate. The activity profile for the immobilized and free enzyme was evaluated using the pH-Stat method as a function of time, temperature, and pH. The Michaelis-Menten kinetic parameters change between the immobilized (V max =127±13 U mg −1 protein; K M =6.28±0.09mM) and free (V max =17±1 U mg −1 protein; K M =0.96±0.01mM) forms of myrosinase, probably due to conformational changes involving the active site as a consequence of enzyme immobilization. Immobilized enzyme activity evaluated as a function of different substrates gave the highest value with nasturtin, the glucosinolate that is typical of several brassicaceae plant roots containing the glucosinolatemyrosinase defensive system. No feedback regulation mechanism was found in the presence of an excess of enzymatic reaction products (i.e. allyl isothiocyanate or sulphate). The high enzyme immobilization yield into Ca-polygalacturonate and its activity preservation under different conditions suggest that the enzyme released by plants at root level could be entrapped in root mucigel in order to preserve its activity.

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Decomposition Products of Allyl Isothiocyanate in Aqueous Solutions

Cited by 90 publications

References 11 publications

Identification, Synthesis, and Enzymology of Non‐natural Glucosinolate Chemopreventive Candidates

Identification, Synthesis, and Enzymology of Non‐natural Glucosinolate Chemopreventive Candidates

Decomposition of sinigrin by methanol/ammonia/water treatment in model systems and mustard (Brassica nigra L.) seed meal

Activity of myrosinase from Sinapis alba seeds immobilized into Ca-polygalacturonate as a simplified model of soil-root interface mucigel

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