Researchers find rare flavoalkaloids and dozens of new phenolics in Cannabis leaves

# What was discovered Scientists at Stellenbosch University analyzed the phenolic chemistry of commercially grown Cannabis leaves and detected 79 phenolic compounds. Of those, 25 had not been reported previously in Cannabis. The team also tentatively identified 16 flavoalkaloids — a rare subgroup of phenolic compounds — marking the first evidence that flavoalkaloids occur in Cannabis leaves.

# Why this matters Researchers and industry typically treat Cannabis leaves as low-value material or waste after harvesting. The new chemical profile shows leaves contain a more complex and varied set of small molecules than expected. Phenolic compounds, including flavonoids and related structures, are of interest because many display antioxidant, anti-inflammatory, or other bioactive properties relevant to biomedical research.

# How the team found them

# What the data show about strain differences The study compared three commercial Cannabis strains grown in South Africa. Most of the detected flavoalkaloids concentrated in one strain, demonstrating pronounced variation in phenolic profiles even among a small set of strains. The authors noted Cannabis already contains more than 750 known metabolites, so the newly reported phenolics add to an already complex chemical picture.

# Implications for research and use The presence of previously unreported phenolics and first-time evidence of flavoalkaloids in Cannabis leaves suggests those leaves could be a source of novel chemicals for pharmacological or biochemical study. Because these compounds were often at low concentrations and difficult to separate, they could have been overlooked by routine analyses. Identifying them opens paths for targeted follow-up: structural confirmation, synthesis or isolation, and biological activity testing.

# What remains to be done The identified compounds were tentatively assigned based on chromatographic separation and mass spectrometric data. Next steps will include definitive structural confirmation, quantification across more strains and growth conditions, and bioactivity screening to assess any therapeutic potential. Broader surveys would clarify how widespread these phenolics are across cultivars and growing regions.

# Bottom line Cannabis leaves, commonly treated as waste, contain a diverse and partially unexplored set of phenolic compounds. Advanced separation and detection methods revealed dozens of compounds not previously reported in the plant and provided the first evidence that flavoalkaloids occur in Cannabis leaves. These findings suggest leaves merit closer chemical and biological study rather than routine disposal.