Cannabis could hold the key to preventing neuro-degenerative diseases like Parkinson’s and Alzheimer’s. Despite its reputation for making people ‘dopey’, it contains a chemical that protects brain cells against ageing, according to new research.
What’s more, the ‘miracle compound’ CBN (cannabinol) is non-psychoactive. In other words, it doesn’t get people high. Senior author Professor Pamela Maher said: “We’ve found cannabinol protects neurons from oxidative stress and cell death – two of the major contributors to Alzheimer’s.
“This discovery could one day lead to the development of new therapeutics for treating this disease and other neuro-degenerative disorders – like Parkinson’s disease.”
Studies on medical cannabis have focused on the active substances THC (delta-9 tetrahydrocannabinol) and CBD (cannabidiol). Little is known about the therapeutic powers of CBN – which is molecularly similar but less heavily regulated.
The team at The Salk Institute in California previously identified the neuro-protective properties. Now they have worked out the mechanism.
Lab experiments showed CBN stops a type of cell death called oxitosis. The process is triggered by the loss of an antioxidant called glutathione.
In experiments, nerve cells were treated with CBN – before oxidative damage was stimulated. Further analysis found CBN boosted mitochondria – the power stations of cells.
In damaged neurons, oxidation caused them to curl up like doughnuts – a change that’s been seen in the brains of people with Alzheimer’s.
Impregnating cells with CBN maintained their healthy shape – and kept them functioning well.
When the test was replicated in nerve cells with mitochondria removed CBN was no longer effective – confirming the finding.
Prof Maher said: “We were able to directly show maintenance of mitochondrial function was specifically required for the protective effects of the compound.”
The study also showed CBN did not activate cannabinoid receptors – which happens during a psychoactive response. So medications containing it would work without causing the individual to become ‘high.’
First author Dr Zhibin Liang said: “CBN is not a controlled substance like THC – the psychotropic compound in cannabis. “Evidence has shown CBN is safe in animals and humans. And because CBN works independently of cannabinoid receptors, it could also work in a wide variety of cells with ample therapeutic potential.”
The study has implications for a range of neuro-degenerative diseases such as Parkinson’s – which is also linked to glutathione loss.
Prof Maher said: “Mitochondrial dysfunction is implicated in changes in various tissues – not just in the brain and ageing. “So the fact this compound is able to maintain mitochondrial function suggests it could have more benefits beyond the context of Alzheimer’s disease.”
She called for further research into CBN and other lesser-studied cannabinoids in the marijuana plant. Prof Maher and colleagues are now seeing if they can reproduce the results in a pre-clinical mouse model. Alzheimer’s and other forms of dementia affect 920,000 people in the UK – a figure that will rise to two million by 2050. Parkinson’s is the fastest growing neurological condition in the world. Around 145,000 people in the UK are living it – a number set to grow to 172,000 by 2030.
The study is in Free Radical Biology and Medicine.