Chemistry of THC and CBD within Marijuana Plants
Chemistry of THC and CBD within Marijuana Plants
How Cannabis Plants Produce THC and CBD
What determines the difference between two strains of cannabis? Why do some people prefer certain strains of cannabis like Lemony Haze or Grape Ape? Marijuana may say certain strains make them feel better in different ways. The reason for these differences between cannabis varieties that smokers can feel is the ratio of two chemicals called THC and CBD.
What are THC and CBD?
THC and CBD are cannabinoids, or in other words, chemicals that have psychoactive effects on your brain. THC is the more potent psychoactive drug present in marijuana. CBD is also psychoactive, but it mainly influences how THC works on the brain. CBD is really what makes cannabis medicine. In what levels these two chemicals are present in a certain marijuana strain determines the strain’s effect. THC and CBD levels are calculated as a ratio. Exactly how much of these chemicals are present in cannabis plants are determined by the plant’s genetic code.
How Do Cannabis Plants Make THC and CBD?
Brace yourself for some light chemistry. Cannabis plants synthesize cannabinoid chemicals from another chemical compound called cannabigerol (CBG). CBG is present in cannabis plants as an acid. The plants make THCA and CBDA acids from CBGA acids. The THCA and CBDA undergo a process called decarboxylation that gives the plants THC and CBD that we calculate.
The decarboxylation process is controlled by heat. A source of heat, like a flame, lighter, or a vaporizer, converts THCA and CBDA into THC and CBD that our bodies can consume.
The Role of Enzymes Determine the Ratio
The process of synthesizing cannabinoids is quite interesting. A single CBGA molecule can turn into either a single THCA molecule or a single CBDA molecule. But never both at the same time. This process is determined by an enzyme. Cannabis plants have two types of enzymes that convert CBGA into THCA or CBDA. For simplicity’s sake, these enzymes will be called E1 and E2. E1 can convert CBGA into THCA, and E2 will convert CBGA into CBDA.
These enzymes are what determine the ratio of THC and CBD in plants. Some plants have only one version of this enzyme, either E1 or E2, while there are other strains with both. Hence the difference in “taste” or “feel” of different versions of cannabis. How much E1 or E2 is present in a plant is determined by the plant’s genetic heritage.
How Does the Human Body Receive THC and CBD?
Chemists call the decarboxylated THC and CBD “activated” forms of THCA and CBDA. The A-forms of THC and CBD are not psychoactive and doesn’t have an effect on the brain. Hence, the THCA and CBDA are called “deactivated” forms.
The chemicals present in cannabis flowers are THCA and CBDA. That’s why marijuana “weed” has to be heated to get the medicinal effect. If you just ate a cannabis flower, it will not get you high and relieve pain. Flowers must be heated to the right temperature to trigger the decarboxylation process that produces psychoactive THC and CBD.
How Strain Genetics of Cannabis Plants Determine THC and CBD Ratio
The psychoactive properties of cannabis plants are determined by how much THC and CBD levels are present in each plant. These two chemical compounds, called cannabinoids, are present as a ratio in different strains of marijuana. This THC to CBD ratio is determined by plant genetics, shared by all plants under one strain.
The Determination of THC and CBD Ratio
Cannabis plants synthesize THC and CBD from a chemical compound called CBG. CBG undergoes a process called decarboxylation that converts each CBG molecule into either THC or CBD. Now, what determines whether a CBD molecule turns into a THC or a CBD molecule is decided by an enzyme.
Cannabis plants have two types of enzymes, which we will refer to here as E1 and E2. Different strains have these enzymes present in three different combinations. Let’s say the E1 enzyme converts CBG to CBD, and the E2 enzyme does the same to THC. The genetic code of the plant determines whether there’s more E1, E2, or both for this conversion process.
How Cannabis Plant Genetics Determine the Presence of E1 and E2 Enzymes
It’s actually a single gene that carries the code for E1 and E2 enzymes in cannabis plants, not two separate genes. If you remember your biology lessons, you know that plants can animals inherit genes from their parents. Like people, marijuana plants get two copies of each gene, one from the mother and another from the father. As such, there are three possible combinations for E1 and E2 genes to be present in a cannabis strain.
If a marijuana plant gets only E1 genes from both mother and father, then that plant could only convert CBG to CBD. However, THC levels will be present but only in very negligible amounts. Likewise, marijuana strains that inherit only E2 genes from both parents can convert CBG only to THC. Then there are the plants that may inherit an E1 gene from one parent and an E2 gene from the other parent. These plants are capable of converting significant amounts of both THC and CBD.
How Marijuana Strains are Categorized by THC and CBD Ratio
Depending on the three E1 and E2 gene combinations mentioned above, marijuana strains fall under three broad categories. Here are brief explanations for each:
CBD Dominant Strains—Cannabis plants that get E1:E1 combinations of genes are called CBD-dominant, or hemp. These plants can only make CBD, and have extremely low amounts of THC. Hemp cannabis is largely CBD dominant. Charlotte’s Web is a famous hemp strain of this type.
Balanced Strains—Cannabis plants that get a combination of E1 and E2 strains can produce largely similar levels of CBD and THC, and are called “balanced” strains. Famous strains of this type include Cannatonic and Harlequin.
THC Dominant Strains—Plants that have E2:E2 genes are THC dominant. These strains of cannabis are the most common because they are the most psychoactive. Pretty much all commercial strains of cannabis are THC dominant, like Girl Scout Cookies and Blue Dream.