METABOLISM OF SOYBEAN ISOFLAVONOIDS AND LIGNANS IN MAN

大豆已被发现含有异黄酮类化合物，也间接含有

Soybeans have been found to contain isoflavonoids and indirect that also mammalian lignan precursors occur in this legume. These diphenolic compounds have in numerous experiments been shown to have antiproliferative properties with regard to many types of cancer and have in addition many other biological effects making them strong candidates for a role as cancer protective agents. The aim of the present investigation is to continue to develop methodology for the isolation, identification and quantitative measurements of lignans and isoflavonoids in human biological fluids, particularly in plasma (the development of a method for feces is intended to be carried out with a subcontract in collaboration with Dr Mindy Kurzer and Dr Joanne Slavin). Studies will also be focused on the type of conjugation of these compounds in plasma, feces and urine. Furthermore it is intended to measure these compounds in already collected feces samples of groups of women consuming different types of habitual diets (macrobiotics, lactovegetarians, omnivores). For these women dietary records and assay results of three isoflavonoids and two lignans in urine are already available. Furthermore it is intended to continue studies on the biological effects of structurally defined chemically synthesized lignans and isoflavonoids on cancer cells in culture, alone and combined with various estrogens and antiestrogens. It is also intended to show by biochemical and gene technological methods that these compounds stimulate sex hormone binding globulin (SHBG) production in hepatic cells and that some of them.inhibit the aromatase (estrogen synthetase) enzyme. The methods to be used and to be developed are mainly based on capillary gas chromatography-mass spectrometry in the selected ion monitoring mode. Purification and conjugate separation is carried out by ion exchange chromatography in microcolumns. Deuterium-labelled lignans (n=3) and isoflavonoids (n=4) have been synthesized and are used as internal standards to correct for losses during preparation of the samples. In some instances radioimmunoassay will be the appropriate method,which has to. be developed. For the biological experiments with cell cultures conventional methodology is used and for the SHBG and aromatase experiments routine biochemical and DNA techniques have been established in the laboratory. This laboratory has provided numerous deuterated and nondeuterated standards of lignans and isoflavonoids to research groups in many countries including many research groups in USA and a newly (15-16.11 1990, Little Rock, USA) formed "Phytoestrogen Research Group" decided that our laboratory will be, if funds are available, the source of standards for these compounds and this synthetic activity.