The Breast Cancer Resistance Protein (BCRP/ABCG2) as a key player in the tissue distribution of flaxseed lignans and their metabolites

Abstract

Lignans are dietary polyphenols, which are metabolized by the gut microbiota into the phytoestrogenic metabolites enterolignans, mainly enterolactone and enterodiol. The Breast Cancer Resistance Protein (BCRP/ABCG2) is an efflux transporter that affects plasma and milk secretion of several drugs and natural compounds. We hypothesized here that Abcg2 could influence levels of lignans and their derived metabolites in target tissues. Consequently, we aimed to evaluate the role of Abcg2 in the tissue distribution of these compounds. We used Abcg2-/- knockout and wild-type male mice fed with a lignanenriched diet for one week and analysed plasma, small intestine, colon, liver, kidneys and testicles. High levels of lignans as well as enterolignans and their glucuronide and sulfate conjugates in the small intestine and colon were detected, with higher concentrations of the conjugates in the wild-type compared with Abcg2-/- mice. Particularly relevant was the detection of 24-fold and 8-fold higher concentrations of enterolactone-sulfate and enterolactone-glucuronide, respectively, in the kidney of Abcg2-/- compared with wild-type mice. In conclusion, our study showed that lignans and their derived metabolites were in vivo substrates of Abcg2, which affected their plasma and tissue levels. These results highlight the role of Abcg2 in influencing the health-beneficial properties of dietary lignans