Objectives: This study aimed to explore the use of D-limonene and some vegetable oils with different amounts of saturated and unsaturated fatty acids as alternative green solvents for microwave-assisted extraction (MAE) of cannabis (Cannabis sativa L.). A standardized cannabis extract was selected to evaluate its potential as a chemopreventive agent.

Materials and methods: Alternative green solvents, powder-to-solvent ratios, and irradiation cycles were determined to optimize the MAE conditions. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to assess the cytotoxic effects against human breast cancer (MCF-7), liver cancer (HepG2), and mammary epithelium (hTert-HME1) cell lines.

Results: The extracts obtained from D-limonene and palm oil contained the highest concentrations of cannabidiol (CBD) and D-tetrahydrocannabinol (THC). A standardized D-limonene extract of cannabis (DEC) containing 0.03% w/w CBD and 1.37% w/w THC was selected for the evaluation of cytotoxic activity compared with CBD and THC. The results revealed that CBD and THC exhibited significant cytotoxic effects (p<0.05) against MCF-7 and HepG2, with the 50% inhibitory concentration (IC₅₀) values of 18.5 and 12.37 μg/mL for CBD and 24.21 and 4.30 μg/mL for THC, respectively, whereas DEC exhibited moderate cytotoxicity against MCF-7 (IC₅₀ of 488.85 μg/mL). However, CBD and THC exhibited significant cytotoxicity (p<0.05) against hTert-HME1 (IC₅₀ values of 35.61 and 25.63 μg/mL, respectively), whereas DEC exhibited low cytotoxicity against hTert-HME1 (IC₅₀ of 1.537.03 μg/mL).

Conclusion: DECs containing appropriate levels of THC and CBD have the potential to be candidates for cancer treatment. However, further investigations are required to improve the efficacy and safety profiles.