Researchers at Stellenbosch University have discovered a number of rare compounds called flavoalkaloids in cannabis leaves for the first time, opening new possibilities for medical applications beyond traditional cannabinoids.
The South African study, published in the Journal of Chromatography A, identified 79 phenolic compounds across three commercial cannabis strains, with 25 compounds reported in cannabis for the first time.
Phenolic compounds are naturally occurring chemicals primarily produced by plants. These compounds are highly valued, making them sought-after ingredients in pharmaceuticals and healthcare products.
Of particular interest were 16 compounds tentatively identified as flavoalkaloids – extremely rare compounds in nature known for their anti-inflammatory, anti-carcinogenic, and antioxidant properties.
“Most plants contain highly complex mixtures of phenolic compounds, and while flavonoids occur widely in the plant kingdom, the flavoalkaloids are very rare in nature,” explained Dr Magriet Muller, the study’s lead author and analytical chemist at Stellenbosch University’s Central Analytical Facility.
The discovery challenges the traditional focus on mood-altering cannabinoids, suggesting that cannabis plant material currently considered waste could have significant medicinal value.
“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,” Dr Muller said.
Interestingly, the flavoalkaloids were found mainly in the leaves of just one strain, highlighting the significant chemical diversity between different cannabis varieties.
The research team used a unique system of liquid chromatography combined with high-resolution mass spectrometry to analyse the complex chemical makeup of cannabis. This approach allowed researchers to separate flavoalkaloids from more abundant flavonoids – a crucial step that enabled their detection for the first time in cannabis.
Dr Muller initially developed her analytical methods for studying rooibos tea, grapes, and wine before applying them to cannabis. The decision proved fortuitous, as cannabis phenolics had not been well characterised despite the plant’s complexity.
Professor André de Villiers, the study’s senior author and leader of the analytical chemistry research group, said he was “blown away” by the findings. “The excellent performance of two-dimensional liquid chromatography allowed separation of the flavoalkaloids from the much more abundant flavonoids, which is why we were able to detect these rare compounds for the first time in cannabis.”
Phenolic compounds, particularly flavonoids, are highly sought after in the pharmaceutical industry for their beneficial properties.
“Our analysis again highlights the medicinal potential of cannabis plant material, currently regarded as waste,” Professor de Villiers concluded. “Cannabis exhibits a rich and unique non-cannabinoid phenolic profile, which could be relevant from a biomedical research perspective.”
The discovery suggests that cannabis leaves and other plant material traditionally discarded during processing could contain valuable compounds for future medical applications, potentially revolutionising how the entire cannabis plant is utilised in healthcare.
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