Phytochemical and biological characterization of a Cannabis sativa L. variety with high cannabidiol content

Non-drug Cannabis sativa L. (Cannabaceae), also known as hemp or industrial hemp as it contains in the whole plant less than 0.2% of Δ9-tetrahydrocannabinol (Δ9-THC), exhibits, in the different varieties, a high titer of non-psychoactive cannabinoids such as cannabidiol (CBD)/cannabidiolic acid (CBDA) or cannabigerol (CBG)/cannabigerolic acid (CBGA) (1). In light of this, recently, it has aroused a growing interest for its possible use in therapy. Cannabinoids represent the specific compounds of C. sativa but other important constituents are also terpenes and polyphenols. Among the non-psychotropic cannabinoids, CBD is the one of greatest interest from the pharmaceutical point of view since it has been found to possess attractive activities such as antioxidant, anti-inflammatory, neuroprotective, anticancer and antimicrobial. The aim of this study was to evaluate and compare the phytochemical profile as well as the antioxidant and antimicrobial properties of two different hexane extracts obtained from flowering tops dried of C. sativa var. fibrante with high CBD content and Δ 9-THC content <0.2%. These two cannabis hexane extracts were obtained from the flowering tops dried as such and after hydrodistillation of the essential oil and have been named CFHE1 and CFHE2, respectively. A preliminary phytochemical screening highlighted a high total phenols content in both extracts investigated (19108 ± 1504.96 mg GAE/100 g FW for CFHE1 and 8587 ± 676.20 mg GAE/100 g FW for CFHE2). These results were corroborated by HPLC-DAD analysis, which showed a high titer of both acid and neutral phytocannabinoids, with CBD as the most abundant compound (275.69 and 392.78 mg/100 g FW). The greater presence of CBD in CFHE2 is due to the decarboxylation of the acid form (CBDA), which occurs during the hydrodistillation process. Moreover, GC-MS analysis leaded to identification of 88 and 56 compounds into CFHE1 and CFHE2, respectively. Cannabinoids are the most abundant compounds in both extracts investigated, although a statistical significant difference in the relative abundance (80.83% and 82.92%, respectively) was highlighted. This difference is mainly attributable to the loss of sesquiterpenes (2.98% vs 0.05%, respectively) and sesquiterpene oxides (2.12% vs 0.04%, respectively) during the hydrodistillation process. Both extracts showed remarkable antioxidant activity, with the following order of potency: TEAC (EC50 4.17 and 5.65 μg/ml) > β-carotene bleaching (EC50 18.05 and 17.28 μg/ml) > ORAC (EC50 12.51 and 56.73 μg/ml) > Iron-chelating activity (EC50 63.43 and 33.02 μg/ml) > FRAP (EC50 80.21 and 144.86 μg/ml) > DPPH (EC50 254.10 and 317.23 μg/ml) for CFHE1 and CFHE2, respectively. A preliminary antimicrobial screening against GRAM+ (Staphylococcus aureus ATCC 6538P), GRAM- (Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 10536) bacteria and fungi (Candida albicans ATCC 10231) highlighted that both extracts did not show any activity against P. aeruginosa and C. albicans. On the contrary, both extracts showed activity against E. coli and S. aureus (MIC values in the range between 4.88 and 9.77 μg/ml for both extracts). Based on these results, we decided to focus our attention on S. aureus clinical strains. Both extracts showed bacteriostatic and bactericidal activity against 19 S. aureus clinical strains (MIC in the range between 4.88 and 9.77 μg/ml and MBC in the range between 9.77 and 156.26 μg/ml, for both CFHE1 and CFHE2). These findings suggest that most likely the remarkable antioxidant and antimicrobial properties highlighted by cannabis extracts are mainly due to phytocannabinoids, but it is also possible that minor compounds present in the extracts such as terpenes might be involved in some type of complementary effect to that of the phytocannabinoids (2). 1) A. Smeriglio, S.V. Giofrè, E.M. Galati, M.T. Monforte, N. Cicero, V. D’Angelo, G. Grassi, C. Circosta (2018) Fitoterapia, 127, 101-108 2) E.B. Russo (2011) Br. J. Pharmacol., 163, 1344-1364