Efficacy of non-psychotropic Cannabis sativa L. standardized extracts in a model of intestinal inflammation

Background: The use of Cannabis sativa L. (Cannabis) was reported by observational studies on inflammatory bowel diseases (IBD) patients. However, this indication is poorly supported by clinical trials. Several pre-clinical studies demonstrated the anti-inflammatory activity of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) at intestinal level. On the contrary, minor cannabinoids, such as cannabigerol (CBG), were less investigated. Moreover, several authors suggested that complex Cannabis extracts might display a higher efficacy in respect to pure cannabinoids against inflammatory disorders. Methods: This study was aimed at investigating the role of Cannabis extracts, standardized in CBD and CBG content, in a model of in vitro-induced intestinal inflammation using CaCo-2 cells. Inflammatory mediators at transcriptional (PCR arrays) and protein level (ELISA assays) were investigated and correlated with enterocyte layer permeability. The two evaluated extracts, A and B, come from the mix of the same Cannabis varieties (Cannabis sativa L. Chemotype III and Chemotype IV), and are standardized in CBD and CBG at the same level, by changing the polarity of the primary extraction solvents. Results: Pro-inflammatory cytokines involved in IBD, such as IL-1β and IFN-γ, induced the expression and the release of chemokines for lymphocytes (CXCL-9, CXCL-10, CCL20) in CaCo-2, while Cannabis extracts (100 µg/mL) or individual compounds (8 µM) showed inhibitory activity. After simulated digestion, extract A abrogated the release of CCL-20, while extract B abrogated the release of CXCL-9 and CXCL-10. The inhibition of CXCL-9 was demonstrated at transcriptional level also. The inhibitory activity paralleled with the content of CBD or CBG, acting at least in part through NF-κB impairment (-42% and - 66%, respectively). However, Cannabis extracts showed greater effect in the CaCo-2-THP-1 co-culture inflammation model compared to individual cannabinoids, thus partially recovering the epithelial barrier measured by transepithelial electrical resistance (TEER), and zonula occludens (ZO-1) expression. Conclusions: Data collected within this study showed the importance of standardization and extraction method reproducibility through manufacturing and process control, besides demanding future investigations focusing on the effect of Cannabis extracts against intestinal inflammation, which show in this context effects higher than individual cannabinoids.