Cannabis leaves yield rare flavoalkaloids with pharmaceutical promise

Cannabis leaves yield rare flavoalkaloids with pharmaceutical promise
by Sophie Jenkins
London, UK (SPX) Aug 15, 2025
Analytical chemists at Stellenbosch University report the first evidence of flavoalkaloids in Cannabis leaves, a rare class of phenolics. Using three South African strains, they cataloged 79 phenolic compounds, including 25 not previously reported in Cannabis. Sixteen were tentatively identified as flavoalkaloids, concentrated in the leaves of a single strain.

Phenolic compounds, especially flavonoids, are prized for antioxidant, anti-inflammatory, and anti-carcinogenic properties. The study, published in the Journal of Chromatography A, underscores the biomedical potential of non-cannabinoid metabolites in plant material often treated as waste.

"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," she explains.

"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."

For her postgraduate work, Dr Magriet Muller developed analytical methods combining comprehensive two-dimensional liquid chromatography with high-resolution mass spectrometry to deeply characterize plant phenolics. After validating them on rooibos tea, grapes, and wine, she applied the toolkit to Cannabis, where phenolics remain comparatively undercharacterized.

"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".

Study leader Prof Andre de Villiers, who heads the analytical chemistry group in SU's Department of Chemistry and Polymer Science, said the chromatographic performance made the flavoalkaloids visible by separating them from dominant flavonoids, enabling the breakthrough detection in leaves.

"Our analysis again highlights the medicinal potential of Cannabis plant material, currently regarded as waste. Cannabis exhibits a rich and unique non-cannabinoid phenolic profile, which could be relevant from a biomedical research perspective," he concludes.

Research Report:Comprehensive two-dimensional liquid chromatographic analysis of Cannabis phenolics and first evidence of flavoalkaloids in Cannabis.