Leaf it to science: SA researchers uncover the hidden power of cannabis leaves

News24

4 days ago

When it comes to cannabis, the spotlight often shines on the buds. But what if the overlooked leaves hold untapped potential for pharmaceuticals?
For most cannabis growers, producing top-quality buds is the ultimate goal. Vibrant colours, frosty trichomes, and a strong, pleasant smell are key signs of a high-quality strain, and growers focus closely on these features.
Given the diverse applications of cannabis for both recreational and medicinal purposes, it's unsurprising that significant emphasis is placed on cultivating high-quality strains.
On the other hand, cannabis plants' leaves are often seen as unhelpful and are believed to drain nutrients from the buds. Consequently, growers frequently remove the leaves to prevent the transfer of energy away from the flowers.
A groundbreaking discovery: Flavoalkaloids
However, researchers from Stellenbosch University (SU) discovered that these leaves may be more valuable than previously thought. For the first time, they identified a rare class of phenolics, flavoalkaloids, in cannabis leaves.
Phenolic compounds, like flavonoids, are natural chemicals found in fruits and plants.
Image by Magriet Muller.
They are known for their health-boosting antioxidant and anti-inflammatory effects and are highly sought after in the pharmaceutical industry due to their antioxidant, anti-inflammatory, and anti-carcinogenic properties.
The researchers studied three strains of cannabis grown in South Africa and identified 79 phenolic compounds, 25 of which were discovered for the first time in cannabis.
Among these were 16 flavoalkaloids, primarily found in the leaves of one specific strain.
Challenges in analysing plant phenolics
Wiida Fourie-Basson
Dr Magriet Muller, an analytical chemist at SU's LC-MS laboratory, and the study's lead author, highlighted the challenges of analysing plant phenolics due to their low concentrations and structural diversity.
'Most plants contain highly complex mixtures of phenolic compounds, and while flavonoids are commonly found across the plant kingdom, flavoalkaloids are exceptionally rare in nature,' she explained.
'We know that cannabis is extremely complex – it contains more than 750 metabolites – but we did not expect such high variation in phenolic profiles between only three strains, nor to detect so many compounds for the first time in the species. Especially the first evidence of flavoalkaloids in cannabis was very exciting.'
A bright future for pharmaceuticals
While people have long used cannabis leaves for eating, making concentrates, and crafting homemade salves, the discovery of these flavonoids marks a breakthrough.
This discovery has the potential to revolutionise pharmaceutical treatments, holding the potential for things like plant-based alternatives to synthetic medicines for combating inflammation, preventing cancer, or improving overall well-being.