Lignans metabolism

Jiao, Y., Davin, L.B. and Lewis, N.G. (1998) Furanofuran lignan metabolism as a function of seed maturation in Sesamum indicum methylenedioxy bridge formation. Phytochemistry, 49, 387-94. 

ROWLAND I R, WISEMAN H, SANDERS T A, ADLERCREUTZ H and BOWEY E A (2000) luteriudividual variation in metabolism of soy isoflavones and lignans influence of habitual diet on equol production by the gut microflora. Nutr Cancer 36, 27-32. 

Recently, some of the specific faecal bacteria involved in the metabolism of dietary isoflavonoids were isolated (Hur et al., 2000). They have been shown to selectively convert genistin and daidzin to their respective aglycones. One of the isolated bacteria, under anoxic conditions, was further shown to metabolise genistein and daidzein to their respective dihydroxy-genistein and dihydroxy-daidzein. In the case of lignans, enterodiol and enterolactone were shown to be excreted in vivo only in rats harbouring a gut microflora (Rowland et al, 1999). 

MORTON M S, MATOS-FERREIRA A, ABRANCHES-MONTEIRO L, CORREIA R, BLACKLOCK N, CHAN P S, CHENG 0, LLOYD s, CHIEH-PING w and GRIFFITHS K (1997) Measurement and metabolism of isoflavonoids and lignans in the human male. Cancer Lett. 114 (1-2) 145-51. 

Substantial individual differences were observed in the response to study breads and the ranges of enterolactone concentration changes in the groups were as follows -54.5-60.0 nmol/1 (placebo), -26.2-101.3 nmol/1 (LP), -19.6-81.8 nmol/1 (HP). This was something that could have been expected as in several studies dietary factors have explained only 10% of the variation in serum enterolactone (Vanharanta et al, 2002b Kilkkinen et al., 2001). This gives further support to the major role of intestinal bacteria in the synthesis of enterolactone. Decreased concentrations of enterolactone may occur due to an increased fiber intake, which may shorten the retention time in the colon and lead to incomplete metabolism of plant lignans. Constipation was earlier shown to be associated with an increased level of serum enterolactone (Kilkkinen et al., 2001). 

Cassidy A, Handley B and Lamuela-Raventos RM. 2000. Isoflavones, lignans and stilbenes — origins, metabolism and potential importance to human health. J Sci Food Agric 80(7) 1044-1062. 

In the meantime, all of the higher intermediates shown in Fig. 2 have been tested and numerous comprehensive surveys of this work have appeared (24, 81—83, 91, 93, 112, 113, 132). Some of these simultaneously describe the formation of secondary aromatic substances in wood, i.e. lignans, tannins, flavonoids, etc., which arise by essentially similar routes coupled with acetate metabolism. A few outstanding recent developments may bear repetition here. 

Heinonen, S., Nurmi, T., Liukkonen, K., Poutanen, K., Wahala, K., Deyama, T., Nishibe, S., and Adlercreutz, H., In vitro metabolism of plant lignans new precursors of mammalian lignans enterolactone and enterodiol, J. Agric. Food Chem., 49, 3178, 2001. 

Bowey E, Aldercreutz A, Rowland I. Metabolism of isoflavones and lignans by the gut microflora a study in germ-free and human flora associated rats. Food Chem. Toxicol. 41, 631-636, 2003. 

Lignans are colorless, crystalline, solid substances widespread in the plant kingdom (mostly as metabolic intermediaries) and having antioxidant, insecticidal, and medicinal properties. Plants containing lignans with anticancer properties include the following ... 

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