In this study (open access), a UHPLC-QToF-MS method was used to quantify 15 desulfoglucosinolates (GSLs) in Brassica vegetables and pungent species. The authors modelled a GSL profile for each species. They report that authenticated plants displayed distinct group–specific profiles. Kale, broccoli, cauliflower, and Brussels sprouts contained higher levels of indole GSLs (glucobrassicin, neo-glucobrassicin) along with glucoraphanin and glucoiberin, whereas turnip, horseradish, wasabi, and watercress were characterised by elevated sinigrin, gluconasturtiin, and total aromatic GSLs
They then used the same method to test 69 dietary supplements, purporting to be brassica-based sources of GSLs, which were purchased on the US retail market.. They do not discuss how LC-MS matrix effects might impact the transferability of the model from fresh vegetables to supplements. Irrespective of this, they report that nominally-similar commercial supplements exhibited substantial compositional variability, with some differing by many orders of magnitude in their GSL content and patterns.
They conclude that this study has revealed group-associated patterns in authenticated materials and highlighted the compositional heterogeneity of commercial products. Many current supplements do not reliably reflect authentic GSL profiles, underscoring challenges for product standardisation, authenticity evaluation, and dietary intake assessment.
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