Absorption of bioactive compounds from steamed broccoli and their effect on plasma glutathione S-transferase activity.

摘要

Cruciferous vegetables are characterized by high amounts of glucosinolates (GLSs) that are hydrolysed to isothiocyanates (ITCs) and other phytochemicals. The aim of this study was to verify the effect of broccoli intake on plasma levels of carotenoids, vitamins and ITCs and on glutathione S-transferase (GST) activity. 20 healthy subjects, characterized for GSTM1 and GSTT1 genotype, participated in a cross-over intervention study (broccoli diet vs. cruciferous-free diet). Subjects consumed a daily portion of broccoli (10 days, 200 g) providing glucosinolates (200 mumol non-indolyl ITCs evaluated by cyclocondensation reaction after myrosinase treatment), vitamin C (about 100 mg) and carotenoids (about 5 mg lutein and beta-carotene). Increases in plasma concn. of folate, carotenoids and ITC were observed. The increase in plasma ITC concn. was independent of GST genotype. Broccoli intervention did not affect plasma GST activity. Results suggest that broccoli is a bioavailable source of diverse compounds whose effects on endogenous defence systems deserve further investigation.