Origins of THC, CBD and CBC in cannabis revealed

In a study published online on 26 December in the scientific journal Plant Biotechnology Journal, the researchers reconstructed extinct enzymes that were active millions of years ago in ancestors of the cannabis plant. In cannabis, enzymes play a key role in the production of cannabinoids - bioactive compounds with, among other things, medicinal potential.

In modern cannabis plants, the distinct bioactive compounds THC, CBD, and CBC are produced by specific, specialized enzymes. The Wageningen researchers show that this was not always the case. The common ancestor of these enzymes was able to produce several cannabinoids at the same time. Only after gene duplications during cannabis evolution did enzymes emerge that specialised in the production of specific compounds.

The researchers used a technique known as ancestral sequence reconstruction. Based on DNA from modern plants, this method makes it possible to infer what enzymes looked like millions of years ago. These ‘ancestral enzymes’ were then resurrected in the laboratory and experimentally tested. The study provides the first experimental evidence that the biosynthesis of cannabinoids such as THC originated within a relatively recent ancestor of cannabis and subsequently became increasingly refined.

The study shows how fundamental research into plant DNA can deepen our understanding of evolution while also enabling innovative applications. The reconstructed ancestral enzymes proved to be easier to produce in micro-organisms, such as yeast cells, than their modern counterparts. This is significant, as cannabinoids are increasingly produced using biotechnological approaches.

“What once seemed evolutionarily ‘unfinished’ turns out to be highly useful,” says WUR researcher Robin van Velzen, who conducted the study together with his colleague Cloé Villard. “These ancestral enzymes are more robust and flexible than their descendants, which makes them very attractive starting points for new applications in biotechnology and pharmaceutical research.”

As an example, Van Velzen points to one of the reconstructed ‘evolutionary intermediates’ that produces CBC very specifically - a cannabinoid known for its anti-inflammatory and analgesic properties.