Glucosinolate Metabolites: Bioavailability, Bioactivity and Clinical Variability

Glucosinolates (GSL) are a broad group of plant secondary metabolites, present in brassica vegetables. Whereas GSL are biologically inactive, they undergo hydrolysis in the presence of the brassica hydrolyzing enzyme, myrosinase. The impact of co-factors and heat on myrosinase activity has been studied for essentially 30 years, together with the bioavailability and bioactivity of resulting metabolites, which include isothiocyanates, nitriles, epithionitriles and indoles. More recently, studies suggest that gut microbiota are able to hydrolyze GSL also, although there is still much to be learned about which strains, how and which metabolites are released and absorbed and how this activity is regulated. Among the metabolites, the most rigorously studied is the isothiocyanate sulforaphane, known to be absorbed, conjugated and to exert many bioactivities, in particular altering redox and triggering nuclear factor erythroid 2–related factor 2 (Nrf2). This pathway is known to impact drug metabolizing enzyme activities as well as a number of physiological pathways including inflammation, and disease states such as diabetes and cardiovascular disease. Much of this work has been carried out in cultured cells and rodents. Yet clinical trials only sometimes reflect effects seen in rodents, sometimes showing extreme variation among subject’s responses, resulting in contrasting results or failure to show efficacy.

The aim of this Research Topic is therefore to explore, with in vitro and animal/human in vivo studies, novel insights into the metabolic fate and activity of dietary GSL and their metabolites. Particular focus will be appreciated on the role of gut microbiota and membrane transporters, in order to better understand the link between Brassica consumption and health effects.

For this reason, articles are welcomed on topics related to:
- Variability in the hydrolysis of GSL and appearance of biologically active products.
- Dose/phytochemical intake–response relationship and pharmacokinetic studies.
- Passage across cell membranes by such compounds.
- Bioactivity of GLS metabolites using physiologically achievable concentrations of circulating metabolites.
- Metabolomics and Nutrigenomics approaches to assess the role of GLS hydrolysis products on physiological outcomes.
-Original Research Articles, Analytical Methods, and Reviews focused on, but not limited to, the above-mentioned themes are welcome.