Valorization of Wild-Type Cannabis indica by Supercritical CO(2) Extraction and Insights into the Utilization of Raffinate Biomass

Supercritical CO(2) extraction (SCCO(2)) extraction of cannabis oil from Indian cannabis (Cannabis indica) leaves was optimized through a central composite design using CO(2) pressure (150–250 bar), temperature (30–50 °C) and time (1–2 h). From the regression model, the optimal CO(2) pressure, extraction temperature and time were 250 bar, 43 °C and 1.7 h, respectively resulting in the experimental yield of 4.9 wt% of cannabis oil via SCCO(2) extraction. The extract contained cannabidiol, tetrahydrocannabivarin, Δ(9)-tetrahydrocannabinol and Δ(8)-tetrahydrocannabinol as well as two terpenoids such as cis-caryophyllene and α-humulene. Besides SCCO(2) extraction of cannabis oil, the raffinate biomass was utilized to extract polyphenols using water as the extraction medium. Cannabis oil and water extractive were investigated for their half-maximal inhibitory concentration (IC(50)) values, which were found to be 1.3 and 0.6 mg/mL, respectively. This is comparable to the commercially available antioxidant such as butylated hydroxytoluene with an IC(50) value of 0.5 mg/mL. This work on SCCO(2) extraction of cannabinoids and other valuable bioactive compounds provides an environmentally sustainable technique to valorize cannabis leaves.