Cannabidiol from inflorescences of Cannabis sativa L.: Green extraction and purification processes

This work investigates an extraction and purification downstream process able to provide cannabidiol (CBD) enriched products starting from inflorescences of Cannabis sativa L. Even though the legislation concerning non-psychoactive Cannabis derivatives is still an open issue, the interest in this compound is justified worldwide by the scientifically demonstrated health beneficial effects of CBD for the treatment of many disorders. For these reasons, the interest in CBD-based formulations, for the sake of readiness for the future market demands, is quite high. Despite the fact that the recent literature is highly addressed to the topic of cannabinoids and their related biological activities, there is still a general lack in strategic proposals aiming at recovering and purifying specifically CBD through scalable processes. In this work, preliminary studies were addressed to convert the main product of the plant metabolism, cannabidiolic acid, to CBD by heat-treatment-induced decarboxylation of the dried biomass. Then, a “green strategy”, supercritical CO2 extraction, enabled to yield a 50 % w/w CBD-enriched oil, avoiding any use of toxic organic solvents. Yields and compositions of methanolic extraction and supercritical CO2 were compared. Results confirmed the enhanced selectivity of supercritical CO2. A winterization process, followed by flash chromatography, successfully removed waxes and the psychotropic fraction, providing an almost 80 % w/w CBD-enriched final product.