The cannabis plant is a reservoir of natural compounds: more than 500 have been identified to date, of which over a hundred are classified as phytocannabinoids. From these we are finding an increasing number of treatments for numerous medical conditions. Alongside THC and CBD, lesser-known cannabinoids are starting to come under the microscope. CBG is one of these.
First isolated from hash in 1964 by Israeli chemists Raphael Mechoulam and Yechiel Gaoni, CBG has been relatively unexplored until the last decade. Until now, there have been no clinical studies with the compound, so what we know about CBG in terms of its therapeutic potential stems from in vitro and animal studies, and anecdotal evidence.
What is CBG?
CBG is non-psychoactive and usually appears in relatively low concentrations in the cannabis plant, although recently some breeders have managed to increase its content. It has gained attention for its purported antibacterial, antitumor, analgesic, anti-inflammatory and neuroprotective properties, putting it in the running alongside CBD for its therapeutic potential, legal status, and the fact that it doesn’t get you high.
CBG is the ‘mother compound’ in the cannabis plant, from which all the psychoactive compounds that we know and love are produced. During the flowering cycle CBGA (the acid form of CBG) is the first cannabinoid that the plant biosynthesises. This is then converted into THCA (the precursor of THC), CBDA (the precursor of CBD), and CBCA (the precursor of CBC and CBL) with the help of enzymes. Once this is complete there is very little CBGA remaining to convert into CBG.
This means that if you want to utilise CBG, you need to harvest the plant earlier than usual (week 6 of an 8 week cycle), before the synthesis of the other cannabinoids has got underway. Because cannabinoid content increases as the plant matures, harvesting early will require a far larger crop harvest than would be needed for a THC or CBD extraction. This is why CBG extracts are currently more expensive than THC or CBD.
To address this issue, breeders have begun to experiment with cross-breeding and genetics to create strains that yield higher amounts of CBG in mature plants, making CBG extraction more affordable. Examples of CBG rich strains include Seedsman’s CBG #1 (16.9% CBG, 0.25% THC) and Hemp Trading’s Panakeia (18% CBG, THC-free).
What people are saying about CBG
There is a growing interest in the compound from breeders and consumers alike. This is largely down to its purported medicinal qualities and the emerging interest in cannabinoid acids among the cannabis patient community.
Sarah Godfrey, a medical cannabis patient and activist in the UK, has found the cannabinoid acids to be extremely beneficial for relieving many of the symptoms associated with severe Crohn’s disease. She reports that CBGA compliments the anti-depressant and anti-inflammatory effects of CBDA, and is currently experimenting with CBGA alongside other cannabinoids. She hopes to complete a detailed review of CBGA and CBG later this year. Other CBG users claim that it reduces the paranoia and anxiety that can accompany a strong THC hit.
What the science is telling us about CBG’s therapeutic potential
Cancer – Preliminary research on animals has demonstrated positive effects for both CBG and CBGA as an anti-tumour therapy for colon cancer. An article published in Carcinogenesis in 2014[i] revealed that CBG inhibited the growth of colorectal cancerous cells and tumours, and a 2018 paper in Cannabis and Cannabinoid Research[ii] demonstrated cytotoxic activity of CBG-rich cannabis extracts on in vitro colon cancer cells.
Inflammatory Bowel Disorder (IBD) – Cannabinoids are widely used by IBD sufferers and anecdotal evidence suggests that a variety of cannabinoids could help relieve the symptoms. In 2013 a paper published in Biochemical Pharmacology[iii] reported on the results of CBG administered to mice with induced colitis, stating that CBG decreased the inflammation in IBD and therefore could provide relief from the suffering of IBD. The authors concluded that it ‘could be considered for clinical experimentation in IBD patients’.
MRSA – The antibacterial effects of CBG were demonstrated in a study[iv] by McMaster University researchers, who found that CBG was effective in mice against drug-resistant MRSA.
Glaucoma – CBG was shown to have potential in the treatment of glaucoma due to it reducing intraocular pressure when administered to the corneas of cats.[v]
Neuroprotectant – A paper published in 2015 reported that CBG was extremely active as a neuroprotectant in mice, improving motor deficits and attenuating other Huntingdon’s Disease symptoms[vi]. A more recent review on the neuroprotective potential of cannabinoids other than THC and CBD, found CBG and its derivatives displayed significant anti-inflammatory effects and were particularly effective in Huntingdon’s disease models.[vii]
Pain relief – Older research suggests that CBG could provide analgesic relief due to it being a GABA uptake inhibitor, which would suggest muscle relaxant properties[viii]
Although further research is clearly needed, preliminary studies and anecdotal evidence indicate considerable promise for CBG in the treatment of various health conditions. As breeders catch on, and strains with higher CBG content become more available, the effects and therapeutic potential of this compound will be more widely accessible.
[i] Borrelli F, Pagano E, Romano B, et al. Colon carcinogenesis is inhibited by the TRPM8 antagonist cannabigerol, a Cannabis-derived non-psychotropic cannabinoid. Carcinogenesis. 2014;35(12):2787-2797. doi:10.1093/carcin/bgu205
[ii] Nallathambi R, Mazuz M, Namdar D, et al. Identification of Synergistic Interaction Between Cannabis-Derived Compounds for Cytotoxic Activity in Colorectal Cancer Cell Lines and Colon Polyps That Induces Apoptosis-Related Cell Death and Distinct Gene Expression. Cannabis Cannabinoid Res. 2018;3(1):120-135. Published 2018 Jun 1. doi:10.1089/can.2018.0010
[iii] Borrelli F, Fasolino I, Romano B, et al. Beneficial effect of the non-psychotropic plant cannabinoid cannabigerol on experimental inflammatory bowel disease. Biochem Pharmacol. 2013;85(9):1306-1316. doi:10.1016/j.bcp.2013.01.017
[iv] Maya A. Farha, Omar M. El-Halfawy, Robert T. Gale, Craig R. MacNair, Lindsey A. Carfrae, Xiong Zhang, Nicholas G. Jentsch, Jakob Magolan, Eric D. Brown. Uncovering the Hidden Antibiotic Potential of Cannabis. ACS Infectious Diseases, 2020; DOI: 10.1021/acsinfecdis.9b00419
[v] Colasanti BK. A comparison of the ocular and central effects of delta 9-tetrahydrocannabinol and cannabigerol. J Ocul Pharmacol. 1990;6(4):259-269. doi:10.1089/jop.1990.6.259
[vi] Valdeolivas S, Navarrete C, Cantarero I, Bellido ML, Muñoz E, Sagredo O. Neuroprotective properties of cannabigerol in Huntington’s disease: studies in R6/2 mice and 3-nitropropionate-lesioned mice. Neurotherapeutics. 2015;12(1):185-199. doi:10.1007/s13311-014-0304-z
[vii] Stone NL, Murphy AJ, England TJ, O’Sullivan SE. A Systematic Review of Minor Phytocannabinoids with Promising Neuroprotective Potential [published online ahead of print, 2020 Jul 1]. Br J Pharmacol. 2020;10.1111/bph.15185. doi:10.1111/bph.15185
[viii] Banerjee SP, Snyder SH, Mechoulam R. Cannabinoids: influence on neurotransmitter uptake in rat brain synaptosomes. J Pharmacol Exp Ther. 1975;194(1):74-81.