Henrik Balslev

Background. Cannabinoids; tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN), might show antibacterial activity. Trema orientalis is a species in the Cannabaceae that is closely related to Cannabis through plastome phylogenetic evidence. This species is widely distributed throughout tropical Asia and is used as traditional medicine, particularly for the treatment of infectious diseases. However, no studies on the antibacterial activity of cannabinoid-containing inflorescences extracts are available. Thus, the aim of this study was to determine cannabinoid content and antibacterial activity of inflorescences fractions from T. orientalis native to Thailand. Methods. We hypothesized that inflorescences from T. orientalis might display cannabinoids similar to Cannabis because of their close taxonomic relationship. We extracted the mature inflorescences and infructescence of T. orientalis in three disparate populations from different Thailand floristic regions. Extractions were subsequently partitioned into hydrophilic and lipophilic fractions using distilled water and chloro- form. The lipophilic extracts were further fractionated by the column chromatography with gradient elution and analyzed by gas chromatography-mass spectrometry (GC- MS). Characterized cannabinoids were used in bioassays with multidrug-resistance bacteria. Results. Lipophilic extracts and fractions of inflorescences from all Thailand floristic regions consistently displayed cannabinoids (THC, CBD and CBN) in various quanti- ties. These extracts exhibited inhibitory activity for Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii strains with minimum inhibitory concentra- tion values varying from 31.25 to 125 mg/mL. Conclusion. Our study is the first to report cannabinoid detection in extracts from inflorescences of T. orientalis, a species in the Cannabaceae. These extracts and their fractions containing cannabinoids showed pronounced antibacterial activity. The use of analytic methods also demonstrated reproducible cannabinoid extraction.