title: Metabolism of hyperforin, the active constituent of St. John's wort, in human liver microsomes.
abstract: The metabolism of hyperforin, one of the pharmacologically most active components of St. John's wort (Hypericum perforatum), was characterized in vitro using human liver microsomes and recombinant heterologously expressed P450 enzymes. A total of 57 hyperforin metabolites were detected. Of those, six were identified as monohydroxylations (M1-M6), while the others were formed via two or more hydroxylation reactions, via dehydrogenation, or by combinations of these reactions. A combined approach of cDNA-expressed recombinant CYPs, CYP-selective chemical inhibitors and correlation with CYP-specific marker activities indicated a central role of the CYP2C and CYP3A families in the metabolism of hyperforin. In addition, hyperforin was found to inhibit CYP2D6 and CYP3A4 model activities quite potently.
authors.affiliation: Novamass Ltd., Kiviharjuntie 11, FI-90220 Oulu, Finland.
authors.forename: Juho
authors.initials: J
authors.lastname: Hokkanen
authors.forename: Ari
authors.initials: A
authors.lastname: Tolonen
authors.forename: Sampo
authors.initials: S
authors.lastname: Mattila
authors.forename: Miia
authors.initials: M
authors.lastname: Turpeinen
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000493:pharmacokinetics; D002853:Chromatography, Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006801:Humans; D006900:Hydroxylation; D020902:Hypericum / Q000737:chemistry*; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D053719:Tandem Mass Spectrometry; D013729:Terpenes / Q000493:pharmacokinetics*
chemical_list: D001643:Bridged Bicyclo Compounds; D013729:Terpenes; D003577:Cytochrome P-450 Enzyme System; D010696:Phloroglucinol; C001654:hyperforin