Tissue distribution of lignans in rats in response to diet, dose-response, and competition with isoflavones

This paper investigates the occurrence and distribution of the lignan metabolites enterodiol (END) and enterolactone (ENL) and the isoflavone daidzein (DAID) in rat tissues using liquid chromatography - electrospray ionisation mass spectrometry (LC – ESI/MSn) following a variety of dietary regimes. Further, we examined the dose-response and distribution of END and ENL in liver, testes, prostate and lung, and investigated the effects of competition between lignans and isoflavones on metabolite distribution. In liver, testes, prostate & lung tissue, dose related increases in END concentration were observed. In the testes, the co-administration of 60 mg/kg SDG with 60 mg/kg isoflavones produced alterations in the resulting metabolite profile, causing increased END concentration and decreased DAID concentration. Results indicate lignan accumulation in tissues occurs, and co-administration of lignans with isoflavones affects the metabolite profile, with effects dependent on tissue type.