Identification of Cannabielsoin a New Metabolite of Cannabidiol Formed by Guinea-Pig Hepatic Microsomal Enzymes, and Its Pharmacological Activity in Mice

Metabolism of cannabidiol (CBD), one of the major components of marihuana, was studied in the guinea pig both in vitroand in vivoAnalyses of metabolites by gas chromatography and gas chromatography-mass spectrometry proved that cannabielsoin (CBE) was formed from CBD as a novel metabolite, and that the amount was about one-sixth of 7-hydroxy-CBD, which was the most abudant metabolite under in vitroconditions in the presence of microsomal monooxygenase(cyto-chrome P-450). CBE was also found in the liver of the guinea pig that was given CBD (100 mg/kg) in- traperitoneally 1 h before sacrifice. The effects of CBE on pentobarbital-induced sleep and body temperature were assessed in the mouse; CBE possessed little activity in either case.