A study from the State University of Rio de Janeiro (Uerj) identified promising analgesic effects in a still little explored substance from the Cannabis sativa plant: cannabigerol (CBG). Tests on rodents showed relief for different types of pain – including neuropathic pain, which is difficult to treat. The study, supported by Faperj, was published in the Scientia Pharmaceutica journal.

According to the World Health Organization (WHO), persistent pain affects about 30% of the global population. Therefore, the search for new effective medications, but with fewer risks of dependence and side effects than traditional opioids, remains a priority.

“Cannabis sativa contains hundreds of compounds. The most well-known are tetrahydrocannabinol (THC), responsible for psychoactive effects, and cannabidiol (CBD), with broad therapeutic potential. Less known, CBG has no psychoactive effect and is a chemical precursor to other cannabinoids,” explains Professor Guilherme Carneiro Montes, project coordinator at the Uerj Institute of Biology (Ibrag/Uerj), in a note released by the university.

How the research was conducted

The study used rodents with increased sensitivity to pain due to prenatal hypoxia-ischemia, a condition that simulates gestational complications. Oral doses of CBG (50 mg/kg) were administered, and three pain models were tested: thermal, inflammatory, and neuropathic.

- Thermal test: when placed on a heated plate at 52 °C, the treated animals took longer to react, suggesting a central analgesic effect.

- Inflammatory test: in a simulation of an ant bite, CBG showed action in both the acute and inflammatory phases.

- Neuropathic pain: after ten days of treatment, there was a significant reduction in painful sensitivity, without side effects such as sedation or motor impairments, common in potent analgesics.

Other results coming in

Another recent study, published in the MDPI journal, investigated the effects of CBG in the treatment of atopic dermatitis (AD), a chronic inflammatory skin condition. Researchers analyzed cellular models and experiments with mice and observed that the compound reduced inflammatory markers and improved skin barrier integrity.

The work suggests that CBG may be a promising candidate for the development of topical therapies aimed at inflammatory skin diseases. Despite the encouraging results, the authors emphasize the need for new clinical investigations in humans to confirm the compound's efficacy and safety.

Results and next steps

“Our molecular analyses showed that, in addition to relieving pain, CBG seems to interfere with mechanisms that contribute to its chronic persistence,” says Bismarck Rezende, a Ph.D. student in Clinical and Experimental Physiopathology at Uerj and the study's first author.

“Furthermore, we observed that the compound acts through different pathways in males and females, which is important to consider in future research and treatments,” he adds.

Despite the results, the researchers reinforce that clinical trials in humans are still needed to prove efficacy, safety, and the ideal forms of administration. 

With information from FAPERJ