TY  - JOUR
A1  - Högger, Petra
A1  - Kurlbaum, Max
A1  - Mülek, Melanie
T1  - Facilitated Uptake of a Bioactive Metabolite of Maritime Pine Bark Extract (Pycnogenol) into Human Erythrocytes
JF  - PLoS ONE
N2  - Many plant secondary metabolites exhibit some degree of biological activity in humans. It is a common observation that individual plant-derived compounds in vivo are present in the nanomolar concentration range at which they usually fail to display measurable activity in vitro. While it is debatable that compounds detected in plasma are not the key effectors of bioactivity, an alternative hypothesis may take into consideration that measurable concentrations also reside in compartments other than plasma. We analysed the binding of constituents and the metabolite δ-(3,4-dihydroxy-phenyl)-γ-valerolactone (M1), that had been previously detected in plasma samples of human consumers of pine bark extract Pycnogenol, to human erythrocytes. We found that caffeic acid, taxifolin, and ferulic acid passively bind to red blood cells, but only the bioactive metabolite M1 revealed pronounced accumulation. The partitioning of M1 into erythrocytes was significantly diminished at higher concentrations of M1 and in the presence of glucose, suggesting a facilitated transport of M1 via GLUT-1 transporter. This concept was further supported by structural similarities between the natural substrate α-D-glucose and the S-isomer of M1. After cellular uptake, M1 underwent further metabolism by conjugation with glutathione. We present strong indication for a transporter-mediated accumulation of a flavonoid metabolite in human erythrocytes and subsequent formation of a novel glutathione adduct. The physiologic role of the adduct remains to be elucidated.
KW  - blood plasma
KW  - cell metabolism
KW  - drug metabolism
KW  - glucose
KW  - glucos metabolism
KW  - glutathione
KW  - plasma proteins
KW  - red blood cells
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96656
ER  - 
TY  - JOUR
A1  - Schreier, Peter
A1  - Binns, Colin
A1  - Högger, Petra
A1  - Wu, Dayong
T1  - It began with citrus
N2  - First Editorial of Open Access Journal "Nutrition and Medicine (NUME)" published by Würzburg University Press: http://nume.de
KW  - Ernährung
KW  - Medizin
KW  - Citrus
KW  - Geschichte
KW  - nutrition
KW  - medicine
KW  - citrus
KW  - history
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-74918
ER  - 
TY  - JOUR
A1  - Högger, Petra
T1  - Nutrition-derived bioactive metabolites produced by gut microbiota and their potential impact on human health
N2  - The functional role of human gut microbiota has attracted substantial interest and recent research has uncovered various aspects of the interplay between the complex communities of microorganisms colonizing the intestine and their hosts’ health. The present review focuses on nutrition-derived bioactive metabolites produced by gut microbiota with potential beneficial effects upon human health. Thereby, the emphasis is on newly generated bacterial metabolites that are not concomitantly present at higher amounts in dietary sources and that have been previously detected in human blood samples. Since a multitude of different substances is generated by gut microbes primarily those metabolites which exert a more pronounced activity than their immediate precursor compound are discussed here. Specifically, the in vitro and in vivo nutridynamics as well as the nutrikinetics of equol, enterolactone / enterodiol, urolithins, 8-prenylnaringenin, 3,4-dihydroxyphenylacetic acid and 5-(3’,4’-dihydroxyphenyl)-g-valerolactone, the short-chain fatty acids butyrate, propionate and acetate, and indole-3-propionic acid are reviewed. Though the metabolites’ mechanism of action and the influence of health conditions on metabolite production are not always fully understood yet, there are many reasons to direct the attention to “gut health”. It could offer new options for preventing or treating a variety of disease states and nutrition-derived microbial products might inspire future drug development.
KW  - Kohlenhydrate
KW  - Tryptophan
KW  - gut microbiota; bioactivation; polyphenols; complex carbohydrates; tryptophan
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-77349
ER  -