In Vitro Metabolism of Plant Lignans:  New Precursors of Mammalian Lignans Enterolactone and Enterodiol

Abstract

The metabolism of the plant lignans matairesinol, secoisolariciresinol, pinoresinol, syringaresinol, arctigenin, 7-hydroxymatairesinol, isolariciresinol, and lariciresinol by human fecal microflora was investigated to study their properties as mammalian lignan precursors. The quantitative analyses of lignan precursors and the mammalian lignans enterolactone and enterodiol were performed by HPLC with coulometric electrode array detector. The metabolic products, including mammalian lignans, were characterized as trimethylsilyl derivatives by gas chromatography-mass spectrometry. Matairesinol, secoisolariciresinol, lariciresinol, and pinoresinol were converted to mammalian lignans only. Several metabolites were isolated and tentatively identified as for syringaresinol and arctigenin in addition to the mammalian lignans. Metabolites of 7-hydroxymatairesinol were characterized as enterolactone and 7-hydroxyenterolactone by comparison with authentic reference compounds. A metabolic scheme describing the conversion of the most abundant new mammalian lignan precursors, pinoresinol and lariciresinol, is presented.

Tools to evaluate estrogenic potency of dietary phytoestrogens:A consensus paper from the EU Thematic Network “Phytohealth” (QLKI-2002-2453)

“…The previous European estimates of lignan intakes do not differ significantly from the lignan intake estimates in the U.S. (Table 2). However, recent reports on the presence of new plant lignan precursors for mammalian lignan production in foods, have changed the view of lignan intake estimates (Heinonen et al, 2001;Milder et al, 2005b). Food composition analyses of lariciresinol (LARI) and pinoresinol (PINO) demonstrated that in many food items these lignans are dominating and may contribute to about 75% of the total lignan intake (Milder et al, 2005a).…”

Cytostatic inhibition of cancer cell growth by lignan secoisolariciresinol diglucoside

“…Potential cancer prevention by dietary lignan glycoside, i.e., secoisolariciresinol 37 diglucoside (SDG), has been suggested to be mediated through its metabolites, enterolactone and 38 enterodiol [1][2][3][4][5]. The chemical structures of SDG and its mammalian metabolite enterolactone 39 are shown in Figure 1.…”

Variation in fasting and non-fasting serum enterolactone concentrations in women of the Malmö Diet and Cancer cohort

“…The mammalian intestinal micro flora converts plant lignans into enterolignans, mainly enterolactone (ENL) (Heinonen et al, 2001).…”