Cannabielsoin as a new metabolite of cannabidiol in mammals

Yamamoto Ikuo Yamamoto, Gohda Hiroshi Gohda, Narimatsu Shizuo Narimatsu, Watanabe Kazuhito Watanabe, Yoshimura Hidetoshi Yoshimura

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Cannabielsoin (CBE) was identified as a novel metabolite of cannabidiol (CBD) in the guinea pig in vivo and in vitro. Its formation by liver microsomes of guinea pigs needed NADPH and molecular oxygen, and was inhibited with SKF 525-A, metyrapone and α-naphthoflavone, indicating participation of cytochrome P-450 (P-450). The CBE-forming activity was highest in guinea pigs, followed by mice, rabbits and rats. In the rat, sex difference was found in the CBE formation (male>female). CBD monomethylether (CBDM) was also biotransformed to CBE monomethylether (CBEM) in the guinea pig in vivo and in vitro. When CBD dimethylether (CBDD) was employed as substrate, 1S,2R-epoxy-CBDD was identified. The results suggest that CBD and CBDM are biotransformed by P-450 to CBE-type metabolites via 1S,2R-epoxides. In pharmacological studies using mice, CBDD and 1S, 2R-epoxy-CBD-2′,6′-diacetate produced hypothermia, and CBD, CBDM and CBEM prolonged pentobarbital-induced sleep. Moreover, 1S,2R-epoxy-CBD-2′,6′-diacetate was examined in the Ames test, but had no mutagenicity.

Original languageEnglish
Pages (from-to)541-546
Number of pages6
JournalPharmacology, Biochemistry and Behavior
Issue number3
Publication statusPublished - Nov 1991


  • 1S,2R-Epoxy intermediate
  • Ames test
  • Barbiturate synergism
  • Cannabidiol
  • Cannabielsoin
  • Cytochrome P-450
  • Guinea pig
  • Hypothermia
  • Liver microsomes
  • Species difference

ASJC Scopus subject areas

  • Biochemistry
  • Toxicology
  • Pharmacology
  • Clinical Biochemistry
  • Biological Psychiatry
  • Behavioral Neuroscience


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