Conversion of cannabidiol to Δ9-tetrahydrocannabinol and related cannabinoids in artificial gastric juice, and their pharmacological effects in mice

Kazuhito Watanabe, Yuka Itokawa, Satoshi Yamaori, Tatsuya Funahashi, Toshiyuki Kimura, Toshiyuki Kaji, Noriyuki Usami, Ikuo Yamamoto

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)

Abstract

Cannabidiol (CBD), a nonpsychoactive cannabinoid, was found to be converted to 9α-hydroxyhexahydrocannabinol (9α-OH-HHC) and 8-hydroxy-iso-hexahydrocannabinol (8-OH-iso-HHC) together with Δ9-tetrahydrocannabinol (Δ9-THC), a psychoactive cannabinoid, and cannabinol in artificial gastric juice. These cannabinoids were identified by gas chromatography-mass spectrometry (GC-MS) by comparison with the spectral data of the authentic compounds. Pharmacological effects of 9α-OH-HHC and 8-OH-iso-HHC in mice were examined using catalepsy, hypothermia, pentobarbital-induced sleep prolongation, and antinociception against acetic acid-induced writhing as indices. The ED 50 values (effective dose producing a 50% reduction of control; mg/kg, i.v.) of 9α-OH-HHC and 8-OH-iso-HHC for the cataleptogenic effect were 8.0 and 30.4, respectively. 8-OH-iso-HHC (10 mg/kg, i.v.) produced a significant hypothermia from 15 to 90 min after administration, although 9α-OH-HHC failed to induce such an effect at the same dose. However, both HHCs (10 mg/kg, i.v.) significantly prolonged pentobarbital-induced sleeping time by 1.8 to 8.0 times as compared with the control solution with 1% Tween 80-saline. The ED50 values (mg/kg, i.v.) of 9α-OH-HHC and 8-OH-iso-HHC for the antinociceptive effect were 14.1 and 39.4, respectively. The present study demonstrated that CBD can be converted to Δ9- THC and its related cannabinoids, 9α-OH-HHC and 8-OH-iso-HHC, in artificial gastric juice, and that these HHCs show Δ9-THC-like effects in mice, although their pharmacological effects were less potent than those of Δ9-THC.

Original languageEnglish
Pages (from-to)16-21
Number of pages6
JournalForensic Toxicology
Volume25
Issue number1
DOIs
Publication statusPublished - Jun 2007

Keywords

  • 8-Hydroxy-iso-hexahydrocannabinol
  • 9α- Hydroxyhexahydrocannabinol
  • Acid-catalyzed cyclization
  • Antinociceptive effect
  • Cannabidiol
  • Δ-Tetrahydrocannabinol

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