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  - Nowotny, Kerstin
A1  - Castro, Jose Pedro
A1  - Hugo, Martin
A1  - Braune, Sabine
A1  - Weber, Daniela
A1  - Pignitter, Marc
A1  - Somoza, Veronika
A1  - Bornhorst, Julia
A1  - Schwerdtle, Tanja
A1  - Grune, Tilman
T1  - Oxidants produced by methylglyoxal-modified collagen trigger ER stress and apoptosis in skin fibroblasts
JF  - Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research
N2  - Methylglyoxal (MG), a highly reactive dicarbonyl, interacts with proteins to form advanced glycation end products (AGEs). AGEs include a variety of compounds which were shown to have damaging potential and to accumulate in the course of different conditions such as diabetes mellitus and aging. After confirming collagen as a main target for MG modifications in vivo within the extracellular matrix, we show here that MG-collagen disrupts fibroblast redox homeostasis and induces endoplasmic reticulum (ER) stress and apoptosis. In particular, MG-collagen-induced apoptosis is associated with the activation of the PERK-eIF2 alpha pathway and caspase-12. MG-collagen contributes to altered redox homeostasis by directly generating hydrogen peroxide and oxygen-derived free radicals. The induction of ER stress in human fibroblasts was confirmed using collagen extracts isolated from old mice in which MG-derived AGEs were enriched. In conclusion, MG-derived AGEs represent one factor contributing to diminished fibroblast function during aging.
KW  - Advanced glycation end products
KW  - Aging
KW  - Apoptosis
KW  - Collagen
KW  - ER stress
KW  - Methylglyoxal
KW  - Redox homeostasis
Y1  - 2018
U6  - https://doi.org/10.1016/j.freeradbiomed.2018.03.022
SN  - 0891-5849
SN  - 1873-4596
VL  - 120
SP  - 102
EP  - 113
PB  - Elsevier
CY  - New York
ER  -