TY - JOUR A1 - Braune, Annett A1 - Maul, Ronald A1 - Schebb, Nils Helge A1 - Kulling, Sabine E. A1 - Blaut, Michael T1 - The red clover isoflavone irilone is largely resistant to degradation by the human gut microbiota N2 - Intestinal bacteria may influence bioavailability and physiological activity of dietary isoflavones. We therefore investigated the ability of human intestinal microbiota to convert irilone and genistein in vitro. In contrast to genistein, irilone was largely resistant to transformation by fecal slurries of ten human subjects. The fecal microbiota converted genistein to dihydrogenistein, 6'-hydroxy-O-desmethylangolensin, and 2-(4-hydroxyphenyl)- propionic acid. However, considerable interindividual differences in the rate of genistein degradation and the pattern of metabolites formed from genistein were observed. Only one metabolite, namely dihydroirilone, was formed from irilone in minor amounts. In further experiments, Eubacterium ramulus, a prevalent flavonoid-degrading species of the human gut, was tested for transformation of irilone. In contrast to genistein, irilone was not converted by E. ramulus. Irilone only differs from genistein by a methylenedioxy group attached to the A-ring of the isoflavone skeleton. This substitution obviously restricts the degradability of irilone by human intestinal bacteria. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/109582333 U6 - https://doi.org/10.1002/mnfr.200900233 SN - 1613-4125 ER - TY - JOUR A1 - Rund, Katharina M. A1 - Heylmann, Daniel A1 - Seiwert, Nina A1 - Wecklein, Sabine A1 - Oger, Camille A1 - Galano, Jean-Marie A1 - Durand, Thierry A1 - Chen, Rongjun A1 - Güler, Faikah A1 - Fahrer, Jörg A1 - Bornhorst, Julia A1 - Schebb, Nils Helge T1 - Formation of trans-epoxy fatty acids correlates with formation of isoprostanes and could serve as biomarker of oxidative stress JF - Prostaglandins & Other Lipid Mediators N2 - In mammals, epoxy-polyunsaturated fatty acids (epoxy-PUFA) are enzymatically formed from naturally occurring all-cis PUFA by cytochrome P450 monooxygenases leading to the generation of cis-epoxy-PUFA (mixture of R,S- and S,R-enantiomers). In addition, also non-enzymatic chemical peroxidation gives rise to epoxy-PUFA leading to both, cis- and trans-epoxy-PUFA (mixture of R,R- and S,S-enantiomers). Here, we investigated for the first time trans-epoxy-PUFA and the trans/cis-epoxy-PUFA ratio as potential new biomarker of lipid peroxidation. Their formation was analyzed in correlation with the formation of isoprostanes (IsoP), which are commonly used as biomarkers of oxidative stress. Five oxidative stress models were investigated including incubations of three human cell lines as well as the in vivo model Caenorhabditis elegans with tert-butyl hydroperoxide (t-BOOH) and analysis of murine kidney tissue after renal ischemia reperfusion injury (IRI). A comprehensive set of IsoP and epoxy-PUFA derived from biologically relevant PUFA (ARA, EPA and DHA) was simultaneously quantified by LC-ESI(-)-MS/MS. Following renal IRI only a moderate increase in the kidney levels of IsoP and no relevant change in the trans/cis-epoxy-PUFA ratio was observed. In all investigated cell lines (HCT-116, HepG2 and Caki-2) as well as C. elegans a dose dependent increase of both, IsoP and the trans/cis-epoxy-PUFA ratio in response to the applied t-BOOH was observed. The different cell lines showed a distinct time dependent pattern consistent for both classes of autoxidatively formed oxylipins. Clear and highly significant correlations of the trans/cisepoxy-PUFA ratios with the IsoP levels were found in all investigated cell lines and C. elegans. Based on this, we suggest the trans/cis-epoxy-PUFA ratio as potential new biomarker of oxidative stress, which warrants further investigation. KW - Isoprostane KW - Trans-epoxy-fatty acid KW - Oxidative stress KW - Biomarker KW - Oxylipin KW - Eicosanoid Y1 - 2019 U6 - https://doi.org/10.1016/j.prostaglandins.2019.04.004 SN - 1098-8823 SN - 2212-196X VL - 144 PB - Elsevier CY - New York ER -