Scientists have identified a rare class of plant compounds in cannabis leaves for the first time, uncovering hidden chemistry in a part of the plant that is often discarded as agricultural waste.
The discovery made by researchers at Stellenbosch University in South Africa, could open new avenues for studying cannabis-derived compounds beyond the well known cannabinoids associated with psychoactive effects.
The study found that cannabis leaves contain uncommon flavoalkaloids rare natural compounds formed from a combination of flavonoids and nitrogen containing alkaloids. Researchers say the finding reveals a far more complex chemical profile within cannabis plants than previously understood.
The research has been published in the Journal of Chromatography A.
Researchers analysed leaf and flower samples from three commercial cannabis strains using advanced chemical detection methods. In total, the team tentatively identified 79 compounds, including 16 flavoalkaloids belonging to four related chemical classes.
According to the researchers, the most unexpected results came from the leaves rather than the flowers. The rare compounds appeared primarily in one cannabis strain, suggesting that certain varieties may contain unique chemical signatures with potential biological value.
Scientists explained that while flavonoids are commonly found across the plant kingdom, flavoalkaloids are considered extremely rare in nature.
The team used two dimensional liquid chromatography combined with high resolution mass spectrometry to separate and identify the compounds. The technology allowed researchers to isolate weaker chemical signals that would normally remain hidden behind more abundant compounds.
Experts say the findings challenge the assumption that discarded cannabis leaves hold little scientific or economic value.
Study highlights major chemical differences between strains
Researchers observed significant chemical variation between the three cannabis strains examined in the study.
One strain showed particularly strong flavoalkaloid signals in its leaves, while the remaining strains displayed much weaker or similar chemical patterns.
Scientists say the findings reinforce a growing understanding that cannabis strains can differ sharply in their internal chemistry due to genetics, selective breeding and environmental conditions.
The study also highlighted how plant tissues develop specialised chemical profiles depending on their functions and exposure to environmental stress.
Leaves, flowers and roots often produce different compounds as part of the plant’s defense mechanisms, researchers noted.
Although the findings are considered promising, scientists cautioned that the compounds were only tentatively identified based on chemical signatures. Further laboratory work using purified samples will be required to confirm their exact molecular structures.
Medical potential remains uncertain as further testing begins
Researchers stressed that the study does not prove any direct medical benefit from the newly identified compounds.
No tests have yet been conducted on humans, animals or cell systems to determine whether the compounds possess anti-inflammatory, antimicrobial or therapeutic properties.
However, scientists believe the discovery creates a new set of targets for future medical and pharmaceutical research. Cannabis studies have historically focused on cannabinoids such as THC and CBD because of their effects on the human nervous system. But researchers say cannabis also produces a wide range of lesser-known molecules that may carry biological significance.
The discovery of rare compounds in cannabis leaves may also alter how the industry views post-harvest plant waste.
Researchers suggest that if future studies confirm useful biological activity, cannabis leaves could become valuable raw material for pharmaceutical extraction and biochemical research rather than being discarded.
At the same time scientists emphasised that more evidence is needed before any medical claims can be made.
For now the study primarily reshapes scientific understanding of cannabis chemistry, showing that one of the plant’s most overlooked parts may contain previously hidden compounds with unexplored potential.