Quantification and in vitro bioaccessibility of glucosinolates and trace elements in Brassicaceae leafy vegetables

Leaf samples from five Brassicaceae species (Brassica carinata, Brassica oleracea, Brassica rapa, Eruca vesicaria and Sinapis alba) were analyzed to determine their contents of glucosinolates and trace elements, and the bioaccessibility of these compounds. Considerable variability in the total contents and glucosinolate profiles was observed in the Brassicaceae species, with the total amounts ranging from 8.5 mu mol/g dw in Brassica oleracea to 32.9 mu mol/g dw in Sinapis alba. Bioaccessibilities of the predominant glucosinolates were moderate, ranging from 13.1% for glucoraphanin to 43.2% for gluconapin, which is particularly relevant as they have been implicated in a variety of anti-carcinogenic mechanisms. Trace element concentrations were: Se (28-160 mu g/Kg dw); Cr (0.31-4.03 mu g/g dw); Ni (0.19-1.53 mu g/g dw); Fe (8.6-18.8 mu g/g dw); Zn (20.8-41.5 mu g/g dw); Ca (6.2-15.2 mg/g dw). Brassicaceae leaves were also moderate dietary sources of Se, Ni, Zn and Ca.