@article{WieseEsatbeyogluWinterhalteretal.2015, author = {Wiese, Stefanie and Esatbeyoglu, Tuba and Winterhalter, Peter and Kruse, Hans-Peter and Winkler, Stephanie and Bub, Achim and Kulling, Sabine E.}, title = {Comparative biokinetics and metabolism of pure monomeric, dimeric, and polymeric flavan-3-ols: A randomized cross-over study in humans}, series = {Molecular nutrition \& food research : bioactivity, chemistry, immunology, microbiology, safety, technology}, volume = {59}, journal = {Molecular nutrition \& food research : bioactivity, chemistry, immunology, microbiology, safety, technology}, number = {4}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1613-4125}, doi = {10.1002/mnfr.201400422}, pages = {610 -- 621}, year = {2015}, abstract = {Scope: Flavan-3-ols are abundant polyphenols in human nutrition and are associated with beneficial health effects. The aim of this study was to comparatively investigate the metabolic fate of (-)-epicatechin, procyanidin B1, and polymeric procyanidins in a randomized cross-over study in humans. Methods and results: Parent compounds, conjugates, and microbial metabolites were determined in plasma, urine, and faeces by HPLC-MS and GC-MS/MS. Glucuronidated, sulfated, and methylated (-)-epicatechin and 5-(3',4'-dihydroxyphenyl)-valerolactone were the dominant metabolites in blood and urine. In addition, minor amounts of procyanidin B1 and 4-hydroxy-5-(3',4'-dihydroxyphenyl) valeric acid and their conjugated metabolites were detected. The formation of 5-(3',4'-dihydroxyphenyl)-valerolactone and 4-hydroxy-5-(3',4'-dihydroxyphenyl) valeric acid varied largely between individuals as well as with the degree of polymerization of flavan-3-ols. Monomer units were not detectable in plasma or urine after procyanidin B1 and polymeric procyanidin intake. No correlation was found between the intake of flavan-3-ols and the occurrence of phenolic acids in blood and urine or the phenolic compound profiles in faeces. Conclusion: In addition to conjugated metabolites derived from the absorption of monomeric flavan-3-ols, 5-(3',4' -dihydroxyphenyl)-valerolactone represents an important in vivo metabolite of (-)-epicatechin and procyanidin B1 produced by the gut microbiota.}, language = {en} } @article{MuellerUllmannWilkensetal.2009, author = {Mueller, Carsten and Ullmann, Kristina and Wilkens, Andrea and Winterhalter, Peter and Toyokuni, Shinya and Steinberg, Pablo}, title = {Potent antioxidative activity of vineatrol (R) 30 grapevine-shoot extract}, issn = {0916-8451}, doi = {10.1271/Bbb.90213}, year = {2009}, abstract = {The health promoting effects of a grapevine-shoot extract named Vineatrol (R) 30, which contains resveratrol (Resv) as well as considerable amounts of Resv oligomers, have recently been investigated. In the present study, we analyzed the free radical scavenging capacity, the ability to inhibit lipid peroxidation, and the capacity to enhance the human glutathione peroxidase 1 (GPx) and the human superoxide dismutase 1 (SOD) gene promoter activities of Vineatrol (R) 30. Vineatrol (R) 30 was able to scavenge the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical cation and led to concentration-dependent inhibition of lipid peroxidation, Vineatrol (R) 30 not being superior to Resv alone in both cases. Vineatrol (R) 30 also enhanced the gene promoter activities of human GPx and SOD expressed in V79 cells, whereas this effect could not be demonstrated for Resv. In summary, the results presented in this study show that the Vineatrol (R) 30 grapevine-shoot extract is a free radical scavenger and potent antioxidant at non- eytotoxic concentrations.}, language = {en} } @article{WieseGaertnerRaweletal.2009, author = {Wiese, Stefanie and Gaertner, Sonja and Rawel, Harshadrai Manilal and Winterhalter, Peter and Kulling, Sabine E.}, title = {Protein interactions with cyanidin-3-glucoside and its influence on alpha-amylase activity}, issn = {0022-5142}, doi = {10.1002/Jsfa.3407}, year = {2009}, abstract = {BACKGROUND: Recent studies indicate that the bioavailability of anthocyanins is extremely low. One of the possible reasons could be their binding to proteins. Therefore, the binding affinity of cyanidin-3-glucoside (Cy3glc) to HSA and alpha-amylase was investigated by the quenching of protein tryptophan fluorescence. From data obtained, the binding constants and the free Gibbs energy were calculated. The changes in conformation of the proteins tested were studied with circular dichroism and the influence of binding on alpha-amylase activity determined. RESULTS: Cy3glc quenched the tryptophan fluorescence and upon ligand binding a change in protein structure was observed related to the corresponding decrease in the et-amylase activity. The association constants of 25 to 77 x 10(3) L mol(-1) were calculated for different proteins, indicating weak interactions of non-covalent nature. Competitive binding with HSA in the presence of 8-anilino-1-naphthalene sulfonic acid suggest involvement of hydrophobic interactions, in the case of HSA the possible site being subdomain IIA. CONCLUSION: The strongest affinity of Cy3glc for HSA being at pH 7 underlines its potential in transport and distribution of the phenolic compounds in organisms. An influence on salivary amylase activity is possible when drinking berry juices with high anthocyanins content.}, language = {en} } @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{WeinertWieseRaweletal.2012, author = {Weinert, Christoph H. and Wiese, Stefanie and Rawel, Harshadrai Manilal and Esatbeyoglu, Tuba and Winterhalter, Peter and Homann, Thomas and Kulling, Sabine E.}, title = {Methylation of catechins and procyanidins by rat and human Catechol-O-Methyltransferase metabolite profiling and molecular modeling studies}, series = {Drug metabolism and disposition : the biological fate of chemicals}, volume = {40}, journal = {Drug metabolism and disposition : the biological fate of chemicals}, number = {2}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, address = {Bethesda}, issn = {0090-9556}, doi = {10.1124/dmd.111.041871}, pages = {353 -- 359}, year = {2012}, abstract = {Catechins and procyanidins are major polyphenols in plant-derived foods. Despite intensive studies in recent years, neither their biochemical nor their toxicological properties have been clarified sufficiently. This study aimed to compare the methylation of catechins and procyanidins by the enzyme catechol-O-methyltransferase (COMT) in vitro. We conducted incubations with rat liver cytosol and human placental cytosol including S-adenosyl-L-methionine. The set of substrates comprised the catechins (-)-epicatechin (EC) and (+)catechin (CAT), the procyanidin dimers B1, B2, B3, B4, B5, and B7 as well as procyanidin trimer C1. After extraction, metabolites were analyzed by means of liquid chromatography-electrospray ionizationmass spectrometry and liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry. EC and CAT were converted to two monomethylated metabolites each by human and rat COMT, with the 3'-O-methyl derivatives being consistently the main metabolites. Furthermore, the flavanyl units of procyanidins were methylated consecutively, leading to monomethylated and dimethylated dimeric metabolites as well as monomethylated, dimethylated, and trimethylated C1 metabolites. The methylation status of each flavanyl unit was determined by means of mass spectrometric quinone-methide fragmentation patterns. In addition, molecular modeling studies were performed with the aim to predict the preferred site of methylation and to verify the experimental data. In conclusion, our results indicate that the degree and position of methylation depend clearly on the three-dimensional structure of the entire substrate molecule.}, language = {en} }