Over the last several decades, researchers have discovered that the cannabis sativa plant produces well over 400 different chemical compounds – many of which are terpeno-phenol compounds which have not been detected in any other plant. Over 100 or so of these cannabinoids that occur naturally in the plant are together known as phytocannabinoids.
Most people are aware of the main phytocannabinoid ∆9-tetrahydrocannabinol (THC). This psychoactive component of cannabis has been extensively studied and has long been known to boast several important health benefits for users. For example, the synthetic THC drug dronabinol (sold as Marinol) was approved for use as far back as the 1980s. Dronabinol is used to manage loss of appetite associated with weight loss in acquired immune deficiency syndrome (AIDS) and to manage nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional treatments.
Unfortunately, one major drawback of THC is that many patients simply don’t want to get “high” and/or are unable to tolerate high doses of the drug. This greatly limits its clinical use for many patients.
Yet the cannabis sativa plant also contains numerous phytocannabinoids that are non-psychoactive but may also be therapeutically useful.
Cannabidiol or CBD is a major non-psychoactive component in cannabis that was originally thought to be biologically inactive for humans, but has since been shown to have a wealth of health benefits for users.
For example, early findings in preclinical and clinical studies have shown CBD to have a wide range of effects that may be therapeutically useful, including anti-seizure, antioxidant, neuroprotective, anti-inflammatory, analgesic, anti-tumor, anti-psychotic, and anti-anxiety properties.
For many patients – especially children with intractable epilepsy – CBD has become a life-saving “miracle cure” that has succeeded where conventional medicines have failed.
But as promising as CBD and THC are, they may not be the only phytocannabinoids worthy of further investigation. There are many other cannabinoids with weak or no psychoactivity at all, but may be therapeutically useful for the development of future pharmacotherapies.
One in particular is CBG.
What is CBG?
Cannabigerol or CBG is another cannabinoid found in the cannabis sativa plant. It is usually found in higher concentrations in hemp.
CBG is a non-psychotropic cannabinoid that was first discovered in 1964 by cannabis research pioneers Yechiel Gaoni and Raphael Mechoulam when they separated a hexane extract of hashish on Florisil. It was the first cannabinoid identified, and its precursor cannabigerolic acid (CBGA) was shown to be the first biogenic cannabinoid formed in the plant.
CBG is the non-acidic form of CBGA – otherwise known as the parent molecule (“mother cannabinoid”) – from which many other cannabinoids are made. Potential targets of CBG actions include transient receptor potential (TRP) channels, cyclooxygenase (COX-1 and COX-2) enzymes, as well as cannabinoid receptors, 5-HT1A receptors and α2 adrenergic receptors.
Normally, CBG appears as a relatively low concentration intermediate in the plant, but recent breeding work has yielded cannabis that has much higher CBGA content. Thanks to an increasing understanding of cannabis science, and the genes that can cause the creation of above average amounts of CBGA, breeders are beginning to enhance their strains with this cannabinoid.
What are some of CBG’s health benefits?
Although there have been relatively few studies that have investigated the pharmacological actions of this compound, the research to date has found CBG exerts several therapeutically beneficial effects.
CBG has been shown to relieve intraocular pressure in the eye, which may be of benefit in the treatment of glaucoma. It has been shown to improve a model of inflammatory bowel disease induced experimentally in mice. CBG can also inhibit the uptake of gamma-Aminobutyric acid (GABA) in the brain, which can decrease anxiety and muscle tension. GABA is the chief inhibitory neurotransmitter in the mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system.
A 2011 review article published in the British Journal of Pharmacology by well-known cannabis research pioneer Ethan B Russo, MD, summarized the studies on CBG.
The review found that it has a relatively weak partial agonistic effect at CB1 and CB2 receptors. CBG’s inhibition of gamma aminobutyric acid (GABA) suggests that it contains muscle relaxant properties.
Studies have also found that CBG has analgesic, anti-erythemic (erythema is a skin condition characterized by redness or rash) antiproliferative (for preventing or retarding the spread of cells into surrounding tissues), antibacterial, antifungal, and anti-glaucoma actions. Studies also suggest that CBG is a bone stimulant – meaning it helps promote bone growth, formation, and fracture healing.
Additional research has shown CBG’s other health benefits:
- CBG is an effective cytotoxic in high dosage on human epithelioid carcinoma.
- It is the next most effective phytocannabinoid against breast cancer after CBD
- It is an antidepressant
- It is a mildly anti-hypertensive agent.
- CBG inhibits keratinocyte proliferation suggesting utility in psoriasis
- It is a relatively potent TRPM8 antagonist for possible application in prostate cancer, and detrusor (muscle) over-activity and bladder pain.
- It is a strong anandamide (bliss molecule) uptake inhibitor
- It is powerful agent against Methicillin-resistant Staphylococcus aureus (MRSA), a drug-resistant bacteria.
Russo points out that CBG may work in synergy with other components of the cannabis plant such as the terpenoids phytol, linalool, caryophyllene oxide and limonene.
Finally, CBG behaves as a potent α-2 adrenoreceptor agonist, supporting analgesic effects previously noted, and moderate 5-HT1A antagonist suggesting antidepressant properties.
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