In a study led by researchers in the Faculty of Science and Technology, Kellyann Clarke (Grad Student, Department of Chemistry), Roy Porter (Senior Lecturer, Department of Chemistry) and collaborators, the chemical composition and biological activities of Jamaican Cannabis sativa essential oils (EOs) were extracted via hydrodistillation as the plants mature from week 8 through to week 12 (including the three phenological stages, inflorescence emerging, flowering and mature buds). EOs from fresh landrace female plants produced yellow, transparent, strongly odorous essential oils in increasing amounts as plants mature (0.01 - 0.11%). The oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector revealing that the oils were complex mixtures with sesquiterpene representing the most abundant class of compounds while monoterpenoid was the least represented at all stages of maturity. The relative percentage of monoterpenes increases as C. sativa mature from week 8 through to week 12 whereas a decrease was observed for sesquiterpenoids. A total of 36 constituents were identified with β-Caryophyllene and α-humulene being the most abundant constituents at all stages of maturity, both having highest levels in week nine. The highest number of constituents was detected in weeks 10 and 11 each having 36 compounds with the lowest number of compounds (27) observed at 8 weeks of maturity. As the plant matured there was a general increase in the composition of β-myrcene, β-phellandrene and β-pinene.

The essential oils were screened for their in vitro antimicrobial and antioxidant properties. All C. sativa essential oils did not exhibit antioxidant properties. However, the EOs exhibit significant to moderate antimicrobial property against the test gram-positive microorganisms, E. faecalis, Streptococcus Group A and Streptococcus Group B with MIC values ranging from 16 g/mL to 125 g/mL.

Reference: Clarke, Kellyann; Porter, Roy; Facey, Petrea; Thoms-Rodriguez, Camille. 2023. “Chemical composition and biological activities of Jamaican Cannabis sativa essential oils as the plant matures”. Flavour and Fragrance Journal.

Photo caption: Top Row (L-R): Kellyann Clarke (Department of Chemistry, The University of the West Indies, Mona); Roy Porter (Department of Chemistry, The University of the West Indies, Mona). Bottom Row (L-R): Petrea Facey (The University of the West Indies, St. Augustine) and Camille Thoms-Rodriguez (The University Hospital of the West Indies).

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