Scientists have identified a rare class of compounds known as flavoalkaloids in marijuana leaves for the first time, adding to evidence that parts of the plant often treated as waste contain a diverse range of potentially useful chemicals.
The research, published in the Journal of Chromatography A, was conducted by analytical chemists Magriet Muller and André de Villiers of Stellenbosch University in South Africa.
Researchers examined the phenolic composition of leaf and flower material from three commercially grown marijuana strains using comprehensive two-dimensional liquid chromatography combined with high-resolution mass spectrometry.
The analysis tentatively identified 79 phenolic compounds, including 25 that had not previously been reported in marijuana.
Among those were 16 compounds tentatively classified as flavoalkaloids, a relatively rare group of naturally occurring compounds combining characteristics of flavonoids and alkaloids.
The researchers said this represents the first evidence of flavoalkaloids in marijuana.
The compounds were not distributed evenly among the plants studied. Flavoalkaloids were detected primarily in leaf extracts from just one of the three strains, highlighting substantial differences in the chemical profiles of different marijuana varieties.
Researchers identified four classes of flavoalkaloids encompassing 16 flavone derivatives, although the precise structures of their alkaloid components could not be conclusively determined from the available mass-spectrometry data.
The study also found notable differences in other phenolic compounds between strains, including several flavones and hydroxycinnamic acid derivatives.
Phenolic compounds have received considerably less research attention in marijuana than cannabinoids such as THC and CBD or compounds such as terpenes. Flavonoids and other phenolics are nevertheless of scientific interest because members of the broader chemical families have demonstrated antioxidant, anti-inflammatory and other biological properties.
The findings do not establish that the newly detected marijuana compounds have therapeutic effects in humans. Instead, researchers say their discovery shows the plant’s non-cannabinoid chemistry is more diverse than previously documented and warrants additional study.
The researchers noted that marijuana contains more than 750 known metabolites and said they did not expect to find such substantial differences in phenolic profiles among only three strains.
The findings may also increase interest in marijuana leaves, which can receive relatively little attention compared with cannabinoid-rich flower.
Researchers concluded that marijuana has a “rich and unique” non-cannabinoid phenolic profile that could have relevance for future biomedical research.
