Well folks, it’s time to take a technical dive into the cannabinoids. This time we dive deep into what is CBD. While this may be somewhat heavy on the chemistry, for those looking for the biochemical background of the hemp/cannabis plant and how it produces all these wonderful molecules, the intellectual rewards will be ample.
Our last post dealt with the so called “mother of all cannabinoids,” CBG, or cannabigerol. While it is true that CBG is a precursor to many cannabinoids, it’s wrong to assume all cannabinoids are derived from CBG. In particular, C3 sidechain cannabinoids (such as THCV) are not derived from CBG. However, many common cannabinoids are derived from CBG. Today, we discuss the biosynthesis of CBD (cannabidiol) from CBG, and explore the chemical properties of CBD.
As shown above, CBGA can be converted to both CBDA (cannabidiolic acid) and THCA (delta-9-tetrahydrocannabinolic acid) through the actions of two enzymes, CBDA synthase, and THCA synthase.
Hemp Plants Vs Cannabis Plants
The difference between a “hemp plant” verses a “cannabis plant” has simply to do with genetics. We find it important to consider the chemistry behind cannabidiol given how popularized the potential health benefits of CBD oil products have become. “Hemp plants” produce far more CBDA synthase than THCA synthase: the opposite is true for THC producing “cannabis plants.” The truth is that hemp and cannabis plants are almost identical, except for the action of those two enzymes. Some strains of hemp are bred and grown to produce fiber. These “fiber” plants still produce CBDA, but in small amounts. But that’s an aside, we are concerned here with CBD.
The biosynthesis of CBDA is straight forward. Activation of the terminal double bond of the geranyl sidechain allows for intramolecular cyclization, which leads to the interesting unsaturated hydrocarbon ring adjacent to the bis-phenol moiety. That’s the CBD backbone: decarboxylation is all that’s needed to convert the CBDA to CBD. Decarboxylation is achieved thru heating, and very cleanly converts CBDA to CBD.
CBD in bulk is a viscous dark oil. It can be further purified by distillation. Of the cannabinoids, CBD is the easiest to handle, since it fluidizes at a lower temp that the others. This makes transfers easy with a little bit of heat.
Next up in our exploration of the cannabinoids will be THC.