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* Corresponding author: D. Di Lorenzo, email [email protected]
The high prevalence of the metabolic syndrome and excessive adipose tissue accumulation (in particular, abdominal obesity) is a major threat to public health, being associated with a substantial decrease in health-related quality of life and an increase in economic costs(1–3). Thus, new strategies related to the long-term prevention and reduction of incidence and severity of CVD and type 2 diabetes need to be initiated. Among these is the identification of beneficial bioactive compounds within many foods, as appropriate dietary strategies that may themselves positively affect disease predisposition and evolution(4).
Lignans are chemicals produced as secondary metabolites(5,6). They occur in the whole plant kingdom and can also be found in fibre-rich foods and particularly concentrated in oilseeds (especially in flaxseed and sesame)(7–9), in cereal grains (e.g. wheat and rye bran), nuts(10), Brassica species, legumes, berries and in many plant-related beverages (tea, coffee and so on)(11). 7-Hydroxymatairesinol (7-HMR) is a dibenzylbutyrolactone plant lignan closely related to matairesinol. It is found at relatively high concentrations in the heartwood of branches and knots of Norway spruce trees (Picea abies)(12) and in various concentrations in plant foods(10–14). The activity and metabolism of 7-HMR has been recently evaluated in rats and in humans, with enterolactone (ENL) being the major metabolite identified(15,16). Other metabolites detected included hydroxyenterolactone, α-conidendrin, conidendric acid, enterodiol (END), allo-7-HMR and unchanged 7-HMR. All of these minor metabolites, including unchanged 7-HMR, were at concentrations many-fold lower than the primary metabolite ENL(15).
In contrast to other well-studied lignans, which are highly concentrated in oilseeds such as sesamin or secoisolariciresinol(17,18), 7-HMR, although also present in oilseeds, was only recently detected in several cereals by applying improved extraction and detection methodologies(10). 7-HMR is found to be concentrated in rye, wheat, triticale, oat, barley, millet, maize bran and amaranth whole grain(10). Thus, as these grains are widely consumed worldwide...