title: In vitro metabolism of (-)-camphor using human liver microsomes and CYP2A6.
abstract: The in vitro metabolism of (-)-camphor was examined in human liver microsomes and recombinant enzymes. Biotransformation of (-)-camphor was investigated by gas chromatography-mass spectrometry (GC-MS). (-)-Camphor was oxidized to 5-exo-hydroxyfenchone by human liver microsomal cytochrome (P450) enzymes. The formation of metabolites of (-)-camphor was determined by the relative abundance of mass fragments and retention time on gas chromatography (GC). CYP2A6 was the major enzyme involved in the hydroxylation of (-)-camphor by human liver microsomes, based on the following lines of evidence. First, of eleven recombinant human P450 enzymes tested, CYP2A6 catalyzed the oxidation of (-)-camphor. Second, oxidation of (-)-camphor was inhibited by (+)-menthofuran and anti-CYP2A6 antibody. Finally, there was a good correlation between CYP2A6 contents and (-)-camphor hydroxylation activities in liver microsomes of 9 human samples.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, Osaka, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Gyoubu
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Miyazawa
mesh_terms: D000891:Anti-Infective Agents, Local / Q000378:metabolism*; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D002164:Camphor / Q000378:metabolism*; D065637:Cytochrome P-450 CYP2A6; D006801:Humans; D006900:Hydroxylation; D008862:Microsomes, Liver / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D000891:Anti-Infective Agents, Local; D002164:Camphor; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6