RT Journal Article SR Electronic T1 METABOLISM OF 8-PRENYLNARINGENIN, A POTENT PHYTOESTROGEN FROM HOPS (HUMULUS LUPULUS), BY HUMAN LIVER MICROSOMES JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 272 OP 279 DO 10.1124/dmd.32.2.272 VO 32 IS 2 A1 Dejan Nikolic A1 Yongmei Li A1 Lucas R. Chadwick A1 Simonida Grubjesic A1 Pia Schwab A1 Peter Metz A1 Richard B. van Breemen YR 2004 UL http://dmd.aspetjournals.org/content/32/2/272.abstract AB The female flowers of hops are used throughout the world as a flavoring agent for beer. Recently, there has been increasing interest in the potential estrogenic properties of hop extracts. Among the possible estrogenic compounds in hops, 8-prenylnaringenin is perhaps most significant due to its high in vitro potency exceeding that of other known phytoestrogens. Since data regarding the pharmacokinetic properties of this compound are lacking, we investigated the in vitro metabolism of 8-prenylnaringenin by human liver microsomes. A total of 12 metabolites were identified, and biotransformation occurred on the prenyl group and the flavanone skeleton. The major site of oxidation was on the terminal methyl groups, and of the two possible isomers, thetransisomer was more abundant. The double bond on the prenyl group was also oxidized to an epoxide that was opened by intramolecular reaction with the neighboring hydroxyl group. On the flavanone skeleton, the major site of oxidation was at 3′position on the B ring. Other metabolites included oxidation at carbon-3 as well as desaturation of the C ring to produce 8-prenylapigenin. An unusual hydroxy quinone product formed byipsohydroxylation of the B ring of 8-prenylnaringenin was also detected. This product was probably an intermediate for the B ring cleavage product, 8-prenylchromone. The American Society for Pharmacology and Experimental Therapeutics