title: Metabolism of the olive oil phenols hydroxytyrosol, tyrosol, and hydroxytyrosyl acetate by human hepatoma HepG2 cells.
abstract: To study the potential hepatic metabolism of olive oil phenols, human hepatoma HepG2 cells were incubated for 2 and 18 h with hydroxytyrosol, tyrosol, and hydroxytyrosyl acetate, three phenolic constituents of olive oil. After incubation, culture media and cell lysates were hydrolyzed with beta-glucuronidase and sulfatase and analyzed by LC-MS. In vitro methylation, glucuronidation, and sulfation of pure phenols were also performed. Methylated and glucuronidated forms of hydroxytyrosol were detected at 18 h of incubation, together with methylglucuronidated metabolites. Hydroxytyrosyl acetate was largely converted into free hydroxytyrosol and subsequently metabolized, yet small amounts of glucuronidated hydroxytyrosyl acetate were detected. Tyrosol was poorly metabolized, with <10% of the phenol glucuronidated after 18 h. Minor amounts of free or conjugated phenols were detected in cell lysates. No sulfated metabolites were found. In conclusion, olive oil phenols can be metabolized by the liver as suggested by the results obtained using HepG2 cells as a hepatic model system.
authors.affiliation: Department of Metabolism and Nutrition, Instituto del Frío (CSIC), C/José Antonio Novais 10, Ciudad Universitaria, E-28040 Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Mateos
authors.forename: Luis
authors.initials: L
authors.lastname: Goya
authors.forename: Laura
authors.initials: L
authors.lastname: Bravo
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D056486:Chemical and Drug Induced Liver Injury / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D020719:Glucuronides / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D013058:Mass Spectrometry; D008745:Methylation; D008862:Microsomes, Liver / Q000378:metabolism; D000069463:Olive Oil; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D010938:Plant Oils / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013431:Sulfates / Q000378:metabolism
chemical_list: D020719:Glucuronides; D000069463:Olive Oil; D010938:Plant Oils; D013431:Sulfates; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol; D010626:Phenylethyl Alcohol