Can a Rare Moss Be Used As a Painkiller?

By Pat Anson, PNN Editor

Cannabis, kava and kratom have some competition. Swiss scientists say a rare moss-like plant could be another natural substance that can treat pain and inflammation. And it’s completely legal.

Radula perrottetii is a member of the liverwort family that only grows in Japan, New Zealand, Tasmania and Costa Rica. It produces a molecule called perrottetinene (PET) that is remarkably similar to tetrahydrocannabinol (THC), the psychoactive ingredient found in cannabis. 

"It's astonishing that only two species of plants, separated by 300 million years of evolution, produce psychoactive cannabinoids," says Jürg Gertsch, PhD, a professor in the Institute of Biochemistry and Molecular Medicine at the University of Bern.



A few year ago, Gertsch learned that dried samples of liverwort were being advertised on the internet as incense that produces so-called "legal highs." At the time, little was known about the pharmacological effects of PET, so Gertsch and his colleagues set out to discover how the substance works.

In studies on laboratory mice, they found that PET reaches the brain very easily and that it activates the same cannabinoid receptors that THC does. PET also has a strong anti-inflammatory effect, which makes it potentially useful as a painkiller.

Because PET produces only a mild degree of euphoria, researchers believe it has low abuse potential and fewer side effects than THC.  

Gertsch and his colleagues recently published their findings in the journal Science Advances. They plan to conduct more extensive animal testing before any clinical trials on humans. And that could take years.

In the meantime, liverwort is already being used for medicinal purposes. “Despite serious safety concerns,” WebMD says liverwort is used to treat gallstones, liver conditions, varicose veins and menopause. Others uses include “strengthening nerves” and stimulating metabolism.

Amazon and eBay advertise liverwort – not as medicine – but to help decorate terrariums and aquariums.