4 ethylphenol

Harlan 8640 Teklad 22/5 rodent diets were used for both control and 0.7% adenine supplemented diets (Madison, WI). Indoxyl sulfate was obtained from gold biotechnology (Olivette, MO). P-cresyl glucuronide and equol 7-glucuronide were purchased from Toronto Research Chemicals (Toronto, ON, Canada) and β-glucuronidase from Helix pomatia (G-7051), pyrocatechol, p-cresol and 4-ethylphenol were obtained from Sigma-Aldrich (St. Louis, MO). Flurazepam was purchased from Cerilliant (Round Rock, TX). Isatin was purchased from Alfa Aesar (Ward Hill, MA). P-cresyl sulfate, phenyl sulfate and 4-ethyl phenyl sulfate were synthesized as previously described58 (link). AST-120 was a kind gift from the Kureha Corporation (Tokyo, Japan).

Terephthalic acid (purity ≥99%) was purchased from Acros Organics and butyltin hydroxide oxide hydrate (97%) from Sigma-Aldrich. 1,4-Cyclohexanedimethanol (>99%) with 70% of the trans isomer, dimethyl terephthalate (DMT, >99%) were purchased from TCI. Isosorbide was acquired from Roquette Frères (≥99.9%). 2,5-Furandicarboxylic acid (FDCA, >99.5%) was provided by Avantium.
p-Cresol (4-methyl phenol, >99%), guaiacol (2-methoxy phenol, >99%) and 4-chlorophenol (>99%) were purchased from ACROS Organics, 4-ethyl phenol (98%), 4-methoxyphenol (99%) and dimethoxybenzene (99%) from Sigma Aldrich and 4-ethyl guaiacol (4-ethyl-2-methoxyphenol, 97%) from ABCR.

2-Methyl-1-propanol, 3-methyl-1-butanol, 3-methyl-butanal, 3-octanone, p-xylene, styrene, benzeneacetaldehyde, phenylethyl alcohol, 4-ethyl-phenol, 2,5-dimethyl-pyrazine, trimethyl-pyrazine, and 3-ethyl-2,5-dimethyl-pyrazine were purchased from Sigma-Aldrich China Inc. (Beijing, China). The 18 amino acid standards, including glycine (Gly), asparagine (Asn), alanine (Ala), glutamic acid (Glu), lysine (Lys), arginine (Arg), proline (Pro), valine (Val), tyrosine (Tyr), isoleucine (Ile), leucine (Leu), tryptophan (Try), serine (Ser), histidine (His), threonine (Thr), methionine (Met), cysteine (Cys) and phenylalanine (Phe), were all purchased from Biosharp.
High-performance liquid chromatography (HPLC)-grade acetonitrile was supplied by Tedia Company (Fairfield, OH, USA). Phenylisothiocyanate (PITC, lot code: 10113227) was purchased from Alfa Aesar Chemical Co. Ltd (Tianjin, China), with a purity higher than 97%. Triethanolamine (TEA, analytical grade) and n-hexane (analytical grade) were purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, China). Pure water was obtained using a Milli-Q purification system (Millipore, Bedford, MA, USA).

4-Hydroxy-3,5-dimethoxybenzyl alcohol was from Alfa Aesar (Haverhill, MA, USA). 4-n-Butylphenol and 4-n-nonylphenol were from Lancaster Synthesis (Haverhill, MA, USA). Ferrous sulphate heptahydrate was from Merck (Burlington, MA, USA). 4-Allylphenol (chavicol) was from Quest International (Naarden, The Netherlands). 4-Allylphenol-2,6-dimethoxyphenol, 4-allyl-2-methoxyphenol (eugenol), 4-(aminomethyl)-2-methoxyphenol hydrochloride (vanillyl amine), 4-sec-butylphenol, 4-cyclohexylphenol, 4-cyclopentylphenol, 4-ethylphenol, 4-n-hexylphenol, 2-hydroxy-benzyl alcohol, 3-hydroxybenzyl alcohol, 4-hydroxybenzyl alcohol, 4-hydroxy-2-methoxybenzyl alcohol, 4-hydroxy-3-methoxybenzyl alcohol (vanillyl alcohol), 5-indanol, 4-isopropylphenol, 2-methoxy-4-methylphenol (para-creosol), 4-methylphenol (para-cresol), 4-n-pentylphenol, 4-n-propylphenol, 5,6,7,8-tetrahydronaphthol and xylenol orange tetrasodium salt were from Sigma-Aldrich (St. Louis, MO, USA). All other chemicals were from commercial sources and of the purest grade available. The pJ404-His-VAO and pBAD-EUGO-His plasmids were a kind gift from Prof. Dr. Marco Fraaije (University of Groningen).

β-cyclodextrin (Wacker, 12.5% H₂O), xanthan gum (Sigma-Aldrich), locust bean gum (Sigma-Aldrich), chitosan (deacetylation degree of 90%), citric acid (Panreac AppliChem) and dibasic sodium phosphate (Na₂HPO₄ ≥ 98%), soapbark (Quillaja saponaria; Sp. ‘quillay’, from Mapuche ‘küllay’) saponin (Sigma-Aldrich, sapogenin content ≥ 10%, India), phenol (99.5%; Panreac, Spain), m-cresol (99%; Sigma, Germany), 4-ethylphenol (99%, Sigma, China), vanillin (99%; Panreac, Spain) and eugenol (99%; Sigma, Germany) were used as received. phenolphthalein and 1-naphthol (≥99%) were obtained from Merck (Germany).

Analytical grade volatile phenols (guaiacol, 4-methylguaiacol, 4-ethylguaiacol and 4-ethylphenol), hexamethylene diisocyanate (HDI), N,N-dimethylformamide (DMF), dibutyltin dilaurate and deuterated NMR solvents (d₆-ethanol, D₂O and DCl) were purchased from Sigma-Aldrich (Castle Hill, NSW, Australia). Analytical grade chloroform was purchased from Chem-Supply (Adelaide, SA, Australia) for polymer precipitation. The deuterium-labelled normalising standard, d₃-4-methylguaiacol, was purchased from CDN Isotopes (Pointe-Claire, Quebec, Canada). Food grade (>98% purity) β-CD and γ-CD were sourced from the IMCD Group (Adelaide, SA, Australia). Stock solutions of volatile phenols and deuterated standards were made in pure ethanol (Thermo Fisher Scientific, Waltham, MA, USA) and stored at –20 °C. Working solutions were prepared in model wine containing 5 g/L of tartaric acid (Thermo Fisher Scientific) and 12% v/v ethanol, and were stored at –4 °C. A commercial red wine (a 2017 Barossa Valley Cabernet Sauvignon) was used for the adsorption study.