Effect of bioaccessibility of phenolic compounds on in vitro anticancer activity of broccoli sprouts

Broccoli is a common dietary vegetable recognized as an important source of biologically-active compounds. To date, research on the chemopreventive activity of broccoli compounds, predominantly conducted on purified substances, has not considered the complexity of interactions between specific substances within the complete extracts. Here, the bioaccessibility of antioxidant compounds of broccoli sprouts was evaluated in conjunction with the inhibitory effect of broccoli sprout extracts on the properties of two prostate cancer cell lines characterized by low (AT-2) and high (MAT-LyLu) metastatic potential. Elevated levels of flavonoids and phenolic acids, and shifts in the relative content of phenolic compounds were observed in the extracts from sprouts subjected to simulated mastication and gastrointestinal digestion in contrast to standard buffer extracts. These differences failed to correlate with extract activity: a similar efficiency in terms of the inhibition of cell proliferation, motility and gap junctional coupling was observed for both broccoli sprout extracts. The attenuated capacity to modulate the activity of pro- and antioxidative enzymes potentially involved in the regulation of cell growth, invasion and intercellular communication observed for digested extracts may account for this effect. To date, this is the first report to address the correlations between the release of biologically active compounds from broccoli sprouts during in vitro conditions, their bioaccessibility and interference with basic cellular properties determining prostate cancer promotion and progression. (C) 2012 Elsevier Ltd. All rights reserved.