In this blog, we will explore the chemistry behind two different versions of delta-10-THC you may encounter.
If you want to learn more about the basics of delta-10-THC in general first, head on over to our Delta-10-Tetrahydrocannabinol blog!
If you were hoping to figure out the difference between delta-8 vs delta-9 vs delta-10, check out our accompanying blog: What is with these THC numbers? Delta-8 vs delta-9 vs delta-10??
Many molecules including THC can be formed in two versions, much like a left and right hand. Why does this matter? The structure of a molecule determines the biological activity. Cannabis plants only produce one form in significant quantities of most cannabinoids such as delta-9, delta-8, and CBD. However, for delta-10, two versions are possible which may produce different effects and can be individually tested for during potency analysis.
These two versions are (6aR,9S)-delta-10-THC and (6aR,9R)-delta-10-THC. The difference whether there is a left or right handed shape along the molecule is indicated by the (9R) or (9S) in the name.
These two versions of delta-10-THC, (6aR,9s) and (6aR,9R), are called stereoisomers. To help understand stereoisomers, consider how your hands fit into gloves - your left hand does not fit easily into a glove for your right hand, and vice versa. Now think of a receptor in the body, such as the CB1 receptor (to which THC binds to produce intoxication), being like a glove. Each receptor has a specific shape that fits one isomer best, just like a glove has a shape that fits one hand or the other best. Since there are two different versions of delta-10-THC, one can fit into the receptor better to activate the receptor more strongly than the other.
For delta-10, the stereochemistry of the isomers is almost like considering whether the molecule has two of the same hands or one left and one right hand. Although this is a simplification, it is the easiest way to consider how the molecules relate to each other.
The (6aR,9R) version of delta-10 has two of the same hands, so the thumbs are pointing in the same direction on both hands, which is known as “cis” orientation. The (6aR,9S) has one left hand and one right hand, which is known as a “trans” configuration. The thumbs of each hand point in opposite directions with the palms facing the same direction, like a normal pair of hands.
These two versions can be written in two different ways:
(6aR,9S)-delta-10-THC = (6aR-trans)-delta-10-THC
(6aR,9R)-delta-10-THC = (6aR-cis)-delta-10-THC
Although most delta-10 products will be a mix of both versions, the delta-10 could also be purified to a single isomer. So which pure version has the correct shape to fit into the CB1 receptor, and would therefore be more effective, if we could choose between them? In a study with pigeons, the (6aR,9R) isomer produced a THC-like effect that was less potent than delta-9, but the (6aR,9S) isomer did not produce any behavior in the pigeons that would indicate a THC-like effect. Unfortunately, there are no reported studies in humans comparing the potency or strength of effects between the two versions. Therefore, at this time, more research seems to be needed to determine the most desirable isomer.
Cannabis plants produce only a single stereospecific isomer of delta-9 in significant quantities which we commonly refer to as delta-9-THC. We know the specific version the plant produces is the most biologically active in terms of classic cannabis effects. Therefore, one may try to infer from delta-9 which version of delta-10 will be more active, however, the molecules have a “hand” at a different position on the skeleton essentially, so it is difficult to make a prediction. At least now that the analytical labs can differentiate between the two forms of delta-10, an understanding of the structure to activity relationship will be developed quickly.
As if this was not complicated enough already, there are two more stereoisomers of delta-10 known as (6aS,9R) and (6aS,9S). Currently, since delta-10 is derived from hemp cannabinoid isomerization (semi-synthetic) rather than via purely synthetic routes, these positions are not currently encountered in significant quantities. The plant derived forms of the mentioned THC isomers possess a (6aR) “hand” rather than (6aS).
Another THC isomer should be mentioned for complete clarity: delta-6a-THC. This one can be confusing as well because it is often written delta-6a,10a-THC. However, delta-6a,10a is synthetically produced and cannot be derived via isomerization of naturally occurring hemp cannabinoids at this time. This is a different THC isomer and is not the same as delta-10-THC. The double bond is between carbons 6a and 10a. This isomer is also called delta-3-THC based on the previously used monoterpenoid numbering system (when delta-10 is called delta-2). If we were to write delta-10 in the same way as delta-6a,10a, it would be called delta-10,10a-THC.
Dibenzopyran = Monoterpenoid
delta-10 = delta-2
delta-6a,10a = delta-3
“Structure-Activity Relationships of the Cannabinoids”
"Drug Discrimination: Applications to Drug Abuse Research"
“Enantiomers, Diastereomers, Identical or Constitutional Isomers”
“Is Delta-10 THC a Natural or Synthetic Cannabinoid?”
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