Microwave-assisted drying and microwave-assisted extraction of Cannabis sativa L.: A mini review

Phytochemicals that bind to cannabinoid receptors are known as phytocannabinoids. They have pharmacological properties like the plant Cannabis sativa L. (Cannabaceae), which produces more than 100 structurally related phytocannabinoids with cannabidiol (1, CBD) and Δ9-tetrahydrocannabinol (2, Δ9-THC or THC) being the two major ones. As phytocannabinoids have remarkable therapeutic and cosmeceutical values, the correct choice of a drying method for harvested C. sativa plant materials and an extraction method for extracting phytocannabinoids and other bioactive compounds is essential to maintain the quality of cannabis products. While microwave-assisted drying (MAD) has been found effective for quick drying of C. sativa for safe storage and further studies, one of the green extraction methods for selective extraction of various secondary metabolites, including phytocannabinoids from C. sativa, is the microwave-assisted extraction (MAE) method, which applies microwaves for heating the solvents and plant tissues in the extraction process. This extraction method increases the kinetics of extraction and offers a shorter extraction time, less solvent, higher extraction rate, and lower cost over the traditional extraction methods of phytocannabinoid extraction. This review article critically appraises microwave-assisted drying techniques and MAE methods of C. sativa based on the information available in the published literature.