A novel study published in the Scientific Report profiled the full spectrum of secondary metabolites in cannabis flowers, leaves, stem barks, and roots and identified compounds that have potential therapeutic effects. Cannabis flower was characterized by highest amount of cannabinoids and terpenoids, the leaf had the highest amount of flavonoids, and the stems bark and root were featured with sterols and triterpenoids.
Figure: Cannabis plant, inflorescences, leaves, root, stem barks, and roots. Figure Cited from [1]
For forensic purposes, cannabis is conceptually divided into hemp and marihuana based on the content of THC. Industrial hemp has less than 0.3% THC, while modern strains of marijuana, generally referred as cannabis if not hemp, contain THC up to 25%. Canada is one of the few countries that have fully legalized medical use of cannabis nationwide. There are more than 400 production sites in Canada and high THC potency strains are predominantly grown in controlled indoor or greenhouse environments. Because cannabinoids are mostly concentrated on the flower tops, commercial growers harvest only the flowers and discard the other plant parts. This is a potentially unnecessary waste.
Figure: Biosynthesis pathways of cannabinoid, terpenoids, sterols, and flavonoids [2, 3]. Figure cited from [1]
Cannabis leaves, stem barks, and roots all have therapeutic potential, as evidenced by their traditional use in various cultures for thousands of years. They each have a wide range of applications, relating primarily with pain and inflammation. For example, in Traditional Chinese Medicine, the leaves were used for asthma, stem barks for traumatic injury and urinary tract infections, and root for traumatic injury and gynecological disorders. Because cannabinoid content is low in cannabis stems and roots, compounds other than cannabinoids may contribute to the therapeutic effects in these plant parts. Dan Jin, the PhD candidate in the University of Alberta and research scientist of PBG BioPharma commented in the article that “As one of the future trends in the cannabis industry, these current plant waste have potential to be turned into natural health products or new medications”.
References
Jin D, Dai K, Xie Z, Chen J (2020) Secondary Metabolites Profiled in Cannabis Inflorescences, Leaves, Stem Barks, and Roots for Medicinal Purposes. Scientific Reports 10:3309
Flores-Sanchez IJ, Verpoorte R (2008) PKS Activities and Biosynthesis of Cannabinoids and Flavonoids in Cannabis sativa L. Plants. Plant and Cell Physiology 49:1767–1782
Andre CM, Hausman J-F, Guerriero G (2016) Cannabis sativa: The Plant of the Thousand and One Molecules. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2016.00019
