@article{RueferKullingMoesenederetal.2009,
  author    = {Ruefer, Corinna E. and Kulling, Sabine E. and Moeseneder, Jutta and Winterhalter, Peter and Bub, Achim},
  title     = {Role of plasma lipoproteins in the transport of the soyabean isoflavones daidzein and daidzein-7-O-beta-D- glucoside},
  issn      = {0007-1145},
  doi       = {10.1017/S0007114509297224},
  year      = {2009},
  abstract  = {Isoflavone intake is associated with various properties beneficial to human health which are related to their antioxidant activity, for example, to their ability to increase LDL oxidation resistance. However, the distribution of isoflavones among plasma lipoproteins has not yet been elucidated in vivo. Therefore, the objective of the present study was to investigate the association between daidzein (DAI) and lipoproteins in human plasma upon administration of the aglycone and glucoside form. Five men aged 22-30 years participated in a randomised, double-blind study in cross-over design. After ingestion of DAI and daidzein-7-O-beta-D-glucoside (DG) (1 mg DAI aglycone equivalents/kg body weight) blood samples were drawn before isoflavone administration as well as 1, 2, 3, 4.5, 6, 8, 10, 12, 24 and 48 h post-dose. Concentrations of DAI in the different lipoprotein fractions (chylomicrons, VLDL, LDL, HDL) and in the non-lipoprotein fraction were analysed using isotope dilution capillary GUMS. The lipoprotein fraction profiles were similar for all subjects and resembled those obtained for plasma in our previously published study. The lipoprotein distribution based on the area under the concentration-time profiles from 0 h to infinity in the different fractions were irrespective of the administered form: non-lipoprotein fraction (53\%) > LDL (20\%) > HDL (14\%) > VLDL (9-5\%) > chylomicrons (2-5\%). Of DAI present in plasma, 47\% was associated to lipoproteins. Concentrations in the different lipoprotein fractions as well as in the non-lipoprotein fraction were always higher after the ingestion of DG than of DAI. Taken together, these results demonstrate an association between isoflavones and plasma lipoproteins in vivo.},
  language  = {en}
}
@article{MortensenKullingSchwartzetal.2009,
  author    = {Mortensen, Alicja and Kulling, Sabine E. and Schwartz, Heidi and Rowland, Ian and Ruefer, Corinna E. and Rimbach, Gerald and Cassidy, Aedin and Magee, Pamela and Millar, Julie and Hall, Wendy L. and Kramer Birkved, Franziska and Sorensen, Ilona K. and Sontag, Gerhard},
  title     = {Analytical and compositional aspects of isoflavones in food and their biological effects},
  issn      = {1613-4125},
  doi       = {10.1002/mnfr.200800478},
  year      = {2009},
  abstract  = {This paper provides an overview of analytical techniques used to determine isoflavones (IFs) in foods and biological fluids with main emphasis on sample preparation methods. Factors influencing the content of IFs in food including processing and natural variability are summarized and an insight into IF databases is given. Comparisons of dietary intake of IFs in Asian and Western populations, in special subgroups like vegetarians, vegans, and infants are made and our knowledge on their absorption, distribution, metabolism, and excretion by the human body is presented. The influences of the gut microflora, age, gender, background diet, food matrix, and the chemical nature of the IFs on the metabolism of IFs are described. Potential mechanisms by which IFs may exert their actions are reviewed, and genetic polymorphism as determinants of biological response to soy IFs is discussed. The effects of IFs on a range of health outcomes including atherosclerosis, breast, intestinal, and prostate cancers, menopausal symptoms, bone health, and cognition are reviewed on the basis of the available in vitro, in vivo animal and human data.},
  language  = {en}
}
@article{RueferGerhauserFranketal.2005,
  author    = {Ruefer, Corinna E. and Gerhauser, C. and Frank, N. and Becker, Hans and Kulling, Sabine E.},
  title     = {In vitro phase II metabolism of xanthohumol by human UDP-glucuronosyltransferases and sulfotransferases},
  issn      = {1613-4125},
  year      = {2005},
  abstract  = {Xanthohumol (XN) is the principal prenylated flavonoid of the hop plant and has recently gained considerable interest due to its potential cancer-chemopreventive effects. However, the metabolism of XN has not yet been investigated in detail. Therefore, we studied the in vitro phase 11 metabolism of XN using nine human recombinant UDP- glucuronosyltransferases (UGT) and five sulfotransferases (SULT). The identification of the metabolites formed was elucidated using HPLC with diode array detection as well as HPLC/API-ES MS. XN was efficiently glucuronidated by UGT 1A8, 1A9, and 1A10; further important UGTs were UGT 1A1, 1A7, and 2B7. With respect to the sulfation reaction, SULT 1A1*2, 1A2, and 1E1 were the most active SULT forms. UGT 1A3, 1A4, and 1A6 as well as SULT 1A3 and 2A1 were of minor importance for the conjugation of XN. Three mono-glucuronides as well as three mono-sulfates were identified. Considering the tissue distribution of the tested UGT and SULT enzyme forms, these findings suggest a prominent role for the glucuronidation and sulfation of XN in the liver as well as in the gastrointestinal tract},
  language  = {en}
}