Details

Autor(en) / Beteiligte

• Matich, Adam J.
• McKenzie, Marian J.
• Lill, Ross E.
• Brummell, David A.
• McGhie, Tony K.
• Chen, Ronan K.-Y.
• Rowan, Daryl D.

Titel

Selenoglucosinolates and their metabolites produced in Brassica spp. fertilised with sodium selenate

Ist Teil von

• Phytochemistry (Oxford), 2012-03, Vol.75, p.140-152

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Broccoli, cauliflower and forage rape fertilised with sodium selenate produced selenoglucosinolates and their aglycones, the methylselenoalkylnitriles and methylselenoalkylisothiocyanates. [Display omitted] ► Broccoli, cauliflower and forage rape were supplemented with sodium selenate. ► Selenium incorporation was into glucosinolates via seleno amino acids. ► Myrosinase hydrolysis of selenoglucosinolates produced seleno-aglycones. ► Selenium-containing aglycones were methylselenoalkyl nitriles and isothiocyanates. ► A possible route to the increased dietary intake of selenium. Glucosinolates are sulphur-containing glycosides found in many Brassica spp. that are important because their aglycone hydrolysis products protect the plant from herbivores and exhibit anti-cancer properties in humans. Recently, synthetically produced selenium analogues have been shown to be more effective at suppressing cancers than their sulphur counterparts. Although selenium is incorporated into a number of Brassica amino acids and peptides, firm evidence has yet to be presented for the presence of selenium in the glucosinolates and their aglycones in planta. In this study broccoli and cauliflower florets, and roots of forage rape, all obtained from plants treated with sodium selenate, were analysed for the presence of organoselenides. GC–MS analysis of pentane/ether extracts identified six organoselenium compounds including selenium analogues of known myrosinase-derived Brassica volatiles: 4-(methylseleno)butanenitrile, 5-(methylseleno)pentanenitrile, 3-(methylseleno)propylisothiocyanate, 4-(methylseleno)butylisothiocyanate, and 5-(methylseleno)pentylisothiocyanate. LC–MS analysis of ethanolic extracts identified three selenoglucosinolates: 3-(methylseleno)propylglucosinolate (glucoselenoiberverin), 4-(methylseleno)butylglucosinolate (glucoselenoerucin), and 5-(methylseleno)pentylglucosinolate (glucoselenoberteroin). LC–MS/MS analysis was used to locate the position of the selenium atom in the selenoglucosinolate and indicates preferential incorporation of selenium via selenomethionine into the methylselenyl moiety rather than into the sulphate or β-thioglucose groups. In forage rape, selenoglucosinolates and their aglycones (mainly isothiocyanates), occurred at concentrations up to 10% and 70%, respectively, of their sulphur analogues. In broccoli, concentrations of the selenoglucosinolates and their aglycones (mainly nitriles) were up to 60% and 1300%, respectively of their sulphur analogues. These findings indicate the potential for the incorporation of high levels of selenium into Brassica glucosinolates.