In vitro binding affinity to human CB1 and CB2 receptors and antimicrobial activity of volatile oil from high potency Cannabis sativa
The volatile oil of Cannabis sativa was tested for its CB1 and CB2 receptor binding along with antimicrobial activities. Biologically guided fractionation resulted in seven fractions (A-G). Fractions C, D and E showed 78.6%, 79.2% and 86.0% binding affinity to CB1 receptor respectively and 94.4%, 89.3% and 78.3% binding affinity CB2 receptors respectively. Seventeen of the reported terpenoids have been also tested for CB1 and CB2 binding affinity, only α-humulene and α-terpeniol showed affinity to CB2 with Ki values of 19.6 and 2.3µM respectively. On the other hand fraction A displayed good antifungal activities against Cryptococcus neoformans (IC50 15.6 ug/mL). Three compounds were isolated and their chemical structures were identified as α-humulene (1), β-caryophyllene (2) and caryophyllene oxide (3). α-humulene showed good and selective antifungal activity against Cryptococcus neoformans with IC50 value of 1.18 µg/mL, while, β-caryophyllene showed weak activity (IC50 19.4 µg/mL). Caryophyllene oxide was inactive.