title: Formation of carbon monoxide during mouse hepatic microsomal oxidative metabolism of cannabidiol; identification and determination.
abstract: Carbon monoxide (CO) was generated in the process of hepatic microsomal oxidative metabolism of cannabidiol (CBD). After the generated CO was reduced to methane (CH4) with a methanizer, CH4 formed was determined by gas chromatography (GC) with a flame ionization detector. After oxidation with hopcalite, CO was also identified as CO2 by gas chromatography/mass spectrometry (GC/MS). The reaction was NADPH-dependent and required molecular oxygen. It was inhibited by addition of some inhibitors of cytochrome P450-dependent monooxygenase. When CBD (191 microM) was incubated with hepatic microsomes of mice in the presence of an NADPH-generating system and oxygen, concentration of CO determined by GC was 4.7 +/- 0.5 ppm/nmol P450 in the incubation atmosphere. Pretreatment with phenobarbital (100 mg/kg, i.p. for 3d) but not 3-methylcholanthrene (80 mg/kg, i.p.) increased the CO formation 78%, while pretreatment with cobaltous chloride (40 mg/kg, i.p. for 3 d) decreased the formation 56%. When CBD was incubated under oxygen-18 gas, molecular oxygen was not incorporated into the CO molecule. 8,9-Dihydro- and 1,2,8,9-tetrahydro-CBDs also produced CO to some extent, whereas CBD monomethyl- and dimethylethers reduced the ability to produce CO. In addition, cannabidivarin and olivetol produced CO, although none of delta 9-tetrahydrocannabinol, cannabinol and d-limonene did. Thus, the resorcinol moiety of CBD is important for CO formation.
authors.affiliation: Shinshin Chemical Industry Co., Ltd, Toyama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Usami
authors.forename: Y
authors.initials: Y
authors.lastname: Tateoka
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: I
authors.initials: I
authors.lastname: Yamamoto
authors.forename: H
authors.initials: H
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D002185:Cannabidiol / Q000378:metabolism*; D002248:Carbon Monoxide / Q000737:chemistry / Q000378:metabolism*; D013759:Dronabinol / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D016166:Free Radical Scavengers; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects; D011506:Proteins / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D011506:Proteins; D002185:Cannabidiol; D013759:Dronabinol; D002248:Carbon Monoxide