In three South African strains, Stellenbosch chemists find the first sign of flavoalkaloids in Cannabis

The sample behind these counts is three strains, all grown commercially in South Africa ^[1]. Against that denominator, 25 new compounds out of 79 phenolics is about 32 percent ^[1]. The tentative flavoalkaloids come to about one compound in five ^[2].

Phenolics are hard to catch. They are often present at very low concentrations, and their structures vary enormously, so separating one from another in a plant extract is difficult ^[7]. Magriet Muller, the first author and an analytical chemist in the LC-MS laboratory of Stellenbosch's Central Analytical Facility ^[6], developed the approach during her postgraduate studies in the university's Department of Chemistry and Polymer Science ^[8]. Separating the extract twice, in two different ways, gives far more resolving power in a sample crowded with closely related compounds ^[9]. High-resolution mass spectrometry then measures each compound's molecular mass with high precision ^[9]. The setup is built to find and assign compounds. The release describes the 16 flavoalkaloid assignments as tentative ^[4].

"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," Muller said ^[10]. Both groups belong to the phenolic family, chemicals plants make for pigmentation, defence and protection from environmental stress ^[14].

For anyone holding a pile of leaves, the distribution is the more useful result. Most of the flavoalkaloids appeared primarily in just one of the three strains ^[5]. "We know that Cannabis 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," Muller said. "Especially the first evidence of flavoalkaloids in Cannabis was very exciting." ^[11] Three samples, one of them carrying most of the signal, cannot show how common that chemistry is across the cultivars farms grow.

The medical interest the release raises comes from flavonoids as a class, many of which are associated with antioxidant, anti-inflammatory and anti-carcinogenic properties ^[13]. The release reports no concentrations and no biological testing for the compounds found in the leaves. The thing this doesn't tell you is whether a leaf holds enough of any one flavoalkaloid to be worth extracting, or whether that compound does anything in a cell or an animal.

The release says leaves, often treated as low-value material or waste, may hold a much richer collection of potentially useful compounds than previously recognised ^[12]. I think the evidence supports that as a reason to analyse leaf material strain by strain before it is thrown out. A case for selling it would need yields per kilogram and activity data.