Extraction and quantification of lignan phytoestrogens in food and human samples

Dietary phytoestrogens have a number of biological effects,including endocr ine disruption, antioxidant potential, and protein tyrosine kinase inhibiti on. Secoisolariciresinol, matairesinol, and-shonanin are lignan phytoestrog ens found-in foodstuffs, especially flaxseed. Normally they are glycosidica lly linked to carbohydrates and in the large intestine are deconjugated fro m the carbohydrate portion by bacteria. The aglycone lignans can be further modified to form the mammalian phytoestrogens enterodiol, enterolactone, a nd enterofuran, which are absorbed into the body and excreted in urine. To assess the health implications of phytoestrogens in general populations, kn owledge of the quantity in the foods eaten is necessary. This article descr ibes a simple preparative procedure for the assay of secoisolariciresinol, matairesinol, and shonanin in foodstuffs after hydrolytic removal of any co njugated carbohydrate. The difficulties in the practical application of the assay procedure are illustrated and. discussed. Analytical results indicat ing the concentration of secoisolariciresinol, matairesinol, and shonanin i n a number of foodstuffs are presented. Also, the mass spectral data of a p utative mammalian phytoestrogen,, called enterofuran, identified in urine a re presented. (C) 2000 Academic Press.