Liverworts may be better for pain relief than cannabis: Swiss study

While the rest of the world discusses the merits of medicinal cannabis, a group of researchers in Switzerland believe a substance found in some liverworts could provide a better alternative.

Liverworts may be better for pain relief than cannabis: Swiss study
The Radula perrottetii liverwort. Photo: Stefan Fischer

The scientists at the University of Bern and Zurich’s ETH technology institute investigated the psychoactive effects of compound perrotetinene (PET), which is found in a small group of liverworts and resembles THC, the active ingredient in cannabis.

Their results show the compound from the Radula perrottetii liverwort easily binds to the brain’s cannabinoid receptors and can dull the sensation of pain.

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PET even has a stronger anti-inflammatory effect than THC, meaning it could have potential medical applications.

It also has the added advantage of being legal and having less of a psychoactive effect than THC, noted researchers in a media release published by the University of Bern.

Researchers in Bern needed a large amount of PET for their study. However, they were unable to obtain enough from the liverworts that grow only in Japan, Costa Rica and New Zealand.

To get around this problem, they enlisted the help of colleagues at the ETH in Zurich who synthesized the THC and PET needed to carry out tests on mice.

“This study is a perfect example of how new concepts of synthesis can enrich our pharmacological knowledge of biologically active natural substances,” said ETH doctoral student Michael Schafroth.

Researchers now say further studies are required, including, for example, preclinical modelling of the effects of PET on chronic and inflammatory pain.

Switzerland currently allows products containing less than one percent THC to be grown and sold while Sativex is the only medicinal cannabis product permitted on the market.

Read also: Could cannabis be the next cash cow for Swiss farmers?


Switzerland backs recreational cannabis trials – with one condition

Switzerland’s Council of States has approved a plan to start cannabis trials for recreational use, but only 'experienced cannabis users' should apply.

Switzerland backs recreational cannabis trials - with one condition
A file photo of the opening of a cannabis clinic in Thailand. Image: Mladen ANTONOV / AFP
The study, which was approved by the Council of States on Wednesday, hopes to find out more about the effects that a controlled legalisation of the drug would have in Switzerland. 

As reported in Swiss news outlet Watson, the government is looking “only for adults who already use cannabis to take part in the study”. 

The proposal was previously approved by Switzerland's lower house – the National Council – in June. 

The decision to embark upon the trial was to be made in March but was delated due to the coronavirus pandemic. 

The experiments are to be carried out in Switzerland’s larger cities. Basel, Bern, Biel, Geneva and Zurich have all expressed interest in conducting the trials. 

Drugs and alcohol: Just how much do the Swiss consume? 

The study wants to understand how the market for cannabis works – and how to combat the black market. The social effects of legalisation are also set to be studied. 

“The models must be tested before starting the debate on whether or not to liberalise cannabis,” said Pierre-Yves Maillard (Social Democrats), a spokesperson for the responsible committee. 

Only people who currently use cannabis – and can prove it – will be allowed to participate. Proof will be determined through a hair sample. 

‘Organic and Swiss’

There remains one sticking point between Switzerland's lower and upper house.

While the National Council has demanded that Swiss-grown, organic cannabis be used as part of the trial – the Council of States has said it does not want to make this a requirement. 

Instead, organic, Swiss-grown cannabis must be used in the trial “wherever possible”, with the Council of States noting that such cannabis is hard to find.

Minister of Health Alain Berset said that a legalisation should benefit Swiss farmers even though “very few producers have experience in this area”. 

200,000 cannabis users in Switzerland

An estimated 200,000 people smoke cannabis products in Switzerland. Those in favour of the new trial argue that this shows the war on drugs has failed – and that legalisation will 

Since 2011, the sale of cannabis products containing up to one percent tetrahydrocannabinol (THC) – the ingredient that makes users high – has been legal in Switzerland.

Regular strength cannabis and other associated products such as hashish are also illegal, although small amounts (less than ten grams) are decriminalised and will only attract a 100 franc on-the-spot fine. 

A poll by the World Health Organisation showed that more teenagers smoked in Switzerland than in any other European country, with 27 percent of 15 year olds having smoked at least once. 

The use of cannabis for medical purposes is also heavily restricted in Switzerland, with only one product – CBD oil – legally available for sale.