Cannabis leaves, often treated as low-value waste, may harbor a richer set of potentially useful chemicals than previously recognized. Analytical chemists at Stellenbosch University examined commercially grown South African cannabis and found evidence of flavoalkaloids — a rare group of phenolic compounds — for the first time in the plant. The findings were published in the Journal of Chromatography A.
The team detected 79 phenolic compounds across three strains, 25 of which had never been reported in cannabis. Sixteen were tentatively identified as flavoalkaloids, and most of those appeared primarily in just one strain. The researchers said the high variation between only three strains was unexpected, especially given that cannabis already contains more than 750 known metabolites.
The discovery was made possible by combining comprehensive two-dimensional liquid chromatography with high-resolution mass spectrometry. This approach separated the scarce flavoalkaloids from the much more abundant flavonoids, which would otherwise obscure them. The authors note that rare compounds can easily be missed with less powerful techniques, and their results point to a need for deeper chemical characterization of cannabis beyond its well-known cannabinoids.