Cannabinoid Extraction from Cannabis sativa
Phytocannabinoids are extracted from the Cannabis Sativa plant. CBD for the majority of products is extracted by CO2 supercritical or solvent extraction methods. Cannabinoid extraction by CO2 is preferred by many as solvent extraction negatively affects the flavour of the extract and can result in toxic residues in the end product.
Cannabinoids are produced in trichomes
The highest concentration of cannabinoids is found in the buds and flowers, although they are present throughout the whole plant. Glandular, hair like structures called trichomes, which produce and store resin, are the main production site for cannabinoids (as shown in Figure 1). Trichomes cover the flowers, leaves and parts of the stem. 1. During the flowering period, the bracts and floral leaves have the highest density of trichomes, and accounts for the abundance of cannabinoids from the flower. 2.
Figure 1: Female flower anatomy showing detailed trichome structure, the main production sites of cannabinoids. 3.
Which chemicals can be found after cannabinoid extraction?
CBD is only one of over 420 known constituents of the plant, 4. and one of over 120 of which are cannabinoids. 5. These phytocannabinoids vary in concentration levels within the plant. The pharmacologically active forms of the cannabinoids are responsible for interacting with CB1 and CB2 receptors of the eCS. 1. CBD is one of the main active forms of the cannabinoids extracted from Cannabis sativa, along with delta 9-tetrahydrocannabinol (Δ9 -THC), cannabinol (CBN), delta 8-tetrahydrocannabinol (Δ8–THC), cannabigerol (CBG), and cannabichromene (CBC). 4.
Prior to extraction, the natural form of the cannabinoids that exist within the trichome are in the acid forms, e.g. cannabidiolic acid (CBDA) tetrahydrocannabinolic acid (THCA), cannabichromenic acid (CBCA). As such, depending on the end use or mode of consumption, moderate heating is required to drive a decarboxylation reaction where the carboxylic acid part of the acid cannabinoid structure is removed, leaving the active, neutral forms of the cannabinoid. 1. The extract containing cannabinoids, terpenes/terpenoids, flavonoids and other plant chemicals is then dissolved in a carrier to produce various CBD products. Alternatively, the extract can undergo further processing to separate and remove unwanted cannabinoids before use.
Cannabinoid Extraction in the UK
In the UK, only seeds and fibre/mature stalk from hemp strains with less than 0.2% THC can be used for CBD and other cannabinoid extraction for non-licensed CBD products. The flowers and buds of all Cannabis sativa plants, regardless of THC content, are controlled under the Misuse of Drugs Act 1971, making it illegal to use them for any purpose. 6.
NEXT: “Cannabinoids and UK Law”
References
1. Nahtigal, I. & Blake, Alexia & Hand, A. & Florentinus-Mefailoski, A. & Hashemi, Haleh & Friedberg, Jeremy. (2016). The pharmacological properties of cannabis. Cannabis: Medical Aspects. 9. 481-491.
2. Happyana, N., Agnolet, S., Muntendam, R., Van Dam, A., Schneider, B. and Kayser, O., 2013. Analysis of cannabinoids in laser-microdissected trichomes of medicinal Cannabis sativa using LCMS and cryogenic NMR. Phytochemistry, 87, pp.51-59.
3. Romero, P., Peris, A., Vergara, K. and Matus, J.T., 2020. Comprehending and improving cannabis specialized metabolism in the systems biology era. Plant Science, 298, p.110571.
4. McCreath, S.B. and Delgoda, R., 2017. Pharmacognosy: Fundamentals, applications and strategies. Academic Press.
5. Pauli, C.S., Conroy, M., Heuvel, B.D.V. and Park, S.H., 2020. Cannabidiol drugs clinical trial outcomes and adverse effects. Frontiers in Pharmacology, 11.
6. Home Office 2019. Factsheet- Cannabis, CBD and other cannabinoids. Available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/825872/factsheet-cannabis-cbd-and-cannabinoids-2019.pdf