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Effect of ascorbic acid and glutathione on the production of nitriles by myrosinase

Bellostas, Natalia; Sorensen, Jens Christian and Sorensen, Hilmer (2006) Effect of ascorbic acid and glutathione on the production of nitriles by myrosinase. Speech at: Second International Biofumigation Symposium, Moscow, Idaho, USA, 26-29 June 2006.

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Summary

Biofumigation is based on the use of glucosinolate-containing plants for the control of soil-borne pest and diseases. Upon tissue damage, glucosinolates are hydrolyzed by endogenous enzymes (myrosinase) and a range of biologically active compounds are formed. Isothiocyanates (ITCs) are the quantitatively dominating products formed at neutral pH. Most of these compounds are volatile and only sparingly soluble in aqueous systems, and depending on the R-group structure and the presence of nucleophiles, further transformation of ITCs occurs. At lower pH and in the presence of certain molecules able to deliver two redox equivalents, the proportion of nitriles increases at the expense of ITC.
The effect of ascorbic acid and glutathione on the production of nitriles at pH 5 was investigated by micellar electrokinetic capillary chromatography (MECC). The presence of 0.25 µmol ascorbic acid increased the production of nitriles although at higher concentrations the proportion of nitriles decreased. Increasing amounts of GSH favored the production of nitriles (40% of the total degradation products were nitriles in the presence of 2 µmol GSH). The oxidation of GSH gives the redox equivalents needed for the liberation of the sulfur from the unstable intermediate of the glucosinolate hydrolysis leading to the formation of the nitrile.


EPrint Type:Conference paper, poster, etc.
Type of presentation:Speech
Keywords:glucosinolate, nitriles, biofumigation, cofactors
Subjects: Crop husbandry > Crop health, quality, protection
Food systems > Food security, food quality and human health
Research affiliation: Denmark > SOAR - Research School for Organic Agriculture and Food Systems
Deposited By: Bellostas Muguerza, Natalia
ID Code:9263
Deposited On:18 Sep 2006
Last Modified:12 Apr 2010 07:34
Document Language:English
Refereed:Not peer-reviewed

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