Don’t toss cannabis leaves. Scientists just found rare compounds inside
Researchers from Stellenbosch University found first evidence of rare phenolic compounds in Cannabis leaves.
- Date:
- September 10, 2025
- Source:
- Stellenbosch University
- Summary:
- Scientists at Stellenbosch University have uncovered a rare class of plant compounds, flavoalkaloids, in Cannabis leaves for the first time. Using advanced two-dimensional chromatography and mass spectrometry, they identified 79 phenolic compounds across three strains, 25 of which had never before been reported in Cannabis. The surprising discovery highlights the complexity of the plant and its untapped biomedical potential beyond cannabinoids, opening new doors for research and medicine.
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Analytical chemists from Stellenbosch University (SU) have provided the first evidence of a rare class of phenolics, called flavoalkaloids, inCannabis leaves.
Phenolic compounds, especially flavonoids, are well-known and sought after in the pharmaceutical industry because of their antioxidant, anti-inflammatory, and anti-carcinogenic properties.
The researchers identified 79 phenolic compounds in three strains ofCannabis grown commercially in South Africa, of which 25 were reported for the first time inCannabis. Sixteen of these compounds were tentatively identified as flavoalkaloids. Interestingly, the flavoalkaloids were mainly found in the leaves of only one of the strains. The results were published in theJournal of Chromatography A recently.
Dr Magriet Muller, an analytical chemist in the LC-MS laboratory of the Central Analytical Facility (CAF) at Stellenbosch University and first author on the paper, says the analysis of plant phenolics is challenging due to their low concentration and extreme structural diversity.
"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 thatCannabis 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 inCannabiswas very exciting."
For her postgraduate studies in SU's Department of Chemistry and Polymer Science, she developed powerful analytical methods combining comprehensive two-dimensional liquid chromatography and high-resolution mass spectrometry for the detailed characterisation of phenolic compounds.
"We were looking for a new application for the methods that I developed, after successfully testing them on rooibos tea, grapes and wine. I then decided to apply the methods toCannabis because I knew it was a complex sample, and thatCannabis phenolics have not been well characterised," she explains.
According to Prof. André de Villiers, her study leader and main author on the paper, he was blown away by the chromatographic results that Muller obtained: "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 inCannabis." He leads the analytical chemistry research group in SU's Department of Chemistry and Polymer Science.
Prof. De Villiers says it is obvious there is still much to gain from studyingCannabis, as the bulk of research in this field to date has been focused on the pharmacological properties of the mood-effecting cannabinoids.
"Our analysis again highlights the medicinal potential ofCannabisplant material, currently regarded as waste.Cannabisexhibits a rich and unique non-cannabinoid phenolic profile, which could be relevant from a biomedical research perspective," he concludes.
Story Source:
Materials provided byStellenbosch University.Note: Content may be edited for style and length.
Journal Reference:
- Magriet Muller, André de Villiers.Comprehensive two-dimensional liquid chromatographic analysis of Cannabis phenolics and first evidence of flavoalkaloids in Cannabis.Journal of Chromatography A, 2025; 1751: 466023 DOI:10.1016/j.chroma.2025.466023
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