Bioavailability and new biomarkers of cruciferous sprouts consumption

The evaluation of the bioavailability of bioactive compounds from cruciferous foods is one challenge in the design of clinical trials for studying their functionality. Currently, studies of bioavailability are mainly based of the analysis of total isothiocyanates and indoles, and sulforaphane metabolites after broccoli consumption. However, as far as we are aware, there are not any biomarkers studied or established for the intake of radish sprouts. In this work, a 7-days-cross-over study with fourteen women was undertaken to compare the bioavailability of glucosinolates from broccoli and radish sprouts. The urinary excretion of isothiocyanates, indoles and their metabolites was analysed by UHPLC-QqQ-MS/MS. For the first time, sulforaphene, sulforaphane-N-acetyl-l-cysteine (SFN-NAC) and 3,3'-diindolylmethane (DIM), were studied as biomarkers of dietary exposure to radish. The SFN-NAC and DIM were already considered biomarkers of broccoli consumption. Higher excretion of conjugated isothiocyanates and constant excretion of indoles were found during the first 12h after ingestion. Metabolites were excreted homogeneously during the study, suggesting no accumulation. The different urinary biomarker profiles provided new information to distinguish between the consumption of broccoli or radish sprouts. The results provide valuable information to better understand the bioavailability of cruciferous bioactives.