Cannabigerol (CBG) reduced inflammatory markers in rheumatoid arthritis joint cells and immune cells, partly by activating the TRPA1 channel — a receptor involved in both pain sensing and inflammation.
Read this if you have rheumatoid arthritis and are curious about cannabinoids beyond THC and CBD — CBG is showing early promise, though it's still at the laboratory stage.
What the researchers found
Most cannabis research focuses on THC and CBD, but the cannabis plant produces over 100 cannabinoids. Cannabigerol (CBG) is a 'minor' cannabinoid that's gaining attention for potential anti-inflammatory properties. This study investigated whether CBG could reduce inflammation in cells taken directly from rheumatoid arthritis (RA) patients.
The researchers tested CBG on two types of cells: rheumatoid arthritis synovial fibroblasts (RASF) — the cells that line inflamed joints in RA — and peripheral blood mononuclear cells (PBMCs, a type of immune cell). They were particularly interested in whether CBG works through a channel called TRPA1, which is involved in both pain sensing and protecting cells from oxidative stress.
CBG increased calcium signaling in TNF-stimulated RASF cells through the TRPA1 channel — but only in inflamed cells, not healthy ones. This selectivity is important: it suggests CBG may preferentially act on inflamed tissue. CBG also reduced the production of key inflammatory molecules including IL-6, IL-8, and MMP-3 (a matrix metalloproteinase that destroys joint tissue in RA).
In immune cells from RA patients, CBG similarly reduced pro-inflammatory cytokine production. The anti-inflammatory effects were partly — but not entirely — blocked by TRPA1 antagonists, meaning CBG likely works through multiple pathways.
Why it matters
Rheumatoid arthritis affects about 1% of the global population, and current treatments — while effective for many — have significant side effects (immunosuppression, liver toxicity, infection risk). If minor cannabinoids like CBG can reduce joint inflammation through different pathways than existing drugs, they could complement current treatments or offer alternatives for patients who don't respond well to standard therapy. The TRPA1 mechanism is particularly interesting because it links pain sensing and inflammation in a way that could address both symptoms simultaneously.
The numbers in context
CBG reduced IL-6, IL-8, and MMP-3 production in TNF-stimulated RASF cells. Calcium signaling through TRPA1 was activated only in inflamed (TNF-stimulated) cells, not in unstimulated cells. TRPA1 antagonists partially blocked CBG's anti-inflammatory effects, indicating TRPA1 is one but not the only mechanism. Effects were also observed in PBMCs from RA patients.
How the study worked
In vitro study using rheumatoid arthritis synovial fibroblasts (RASF) stimulated with TNF for 72 hours, and peripheral blood mononuclear cells (PBMCs) from RA patients. Cells were treated with CBG and TRPA1 antagonists to determine mechanism of action. Inflammatory markers (IL-6, IL-8, MMP-3, cytokines), calcium signaling, and TRPA1-dependent effects were measured.
Who was studied
Rheumatoid synovial fibroblasts and peripheral blood mononuclear cells in vitro.
What this study cannot tell us
In vitro study only — cells in a dish don't behave the same as cells in a living joint. The anti-inflammatory effects of CBG in lab conditions may not translate to clinical benefit in patients. No dosing information relevant to human use can be derived from this study. The partial dependence on TRPA1 means the full mechanism isn't understood. RA has multiple inflammatory pathways; reducing a few cytokines may not produce meaningful clinical improvement.
How to read the evidence
This is a laboratory (in vitro) study using cells from RA patients. It provides mechanistic insights but is far from clinical evidence. Many promising lab findings don't translate to effective treatments in living patients.
When this study was published
Published in 2023. CBG research is in very early stages; clinical trials for RA are likely years away.
The bigger picture
This adds CBG to the expanding roster of cannabinoids with potential therapeutic applications, alongside the CBD immunity research in RTHC-00098. The TRPA1 mechanism is distinct from the CB1/CB2 receptor pathways that most cannabinoid research focuses on, suggesting minor cannabinoids may offer pharmacological diversity beyond what THC and CBD provide. For RA patients already using cannabis products, this research points to CBG as a potentially useful component.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Would CBG show anti-inflammatory effects in animal models of RA? What dose of CBG would a person need to achieve anti-inflammatory concentrations in joint tissue? Could CBG complement existing RA medications, or would it interact with them? Does the TRPA1 selectivity for inflamed tissue mean CBG would have fewer off-target effects than broad immunosuppressants?
Read the original research
Anti-Inflammatory Effects of Cannabigerol in Rheumatoid Arthritis Synovial Fibroblasts and Peripheral Blood Mononuclear Cell Cultures Are Partly Mediated by TRPA1.
International journal of molecular sciences, 24(1)
The International Journal of Molecular Sciences is a well-regarded journal focusing on molecular biology and related fields.
Citation
Lowin, Torsten; Tigges-Perez, Marianne Sofia; Constant, Eva; Pongratz, Georg. (2023). Anti-Inflammatory Effects of Cannabigerol in Rheumatoid Arthritis Synovial Fibroblasts and Peripheral Blood Mononuclear Cell Cultures Are Partly Mediated by TRPA1.. International journal of molecular sciences, 24(1). https://doi.org/10.3390/ijms24010855
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