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Scientists discover cannabinoid 30 times "stronger" than THC

Move over, THC: a report from a group of scientists in Italy says there's a new compound on the block, and it may pack a punch.

Tetrahydrocannabiphorol, or THCP, could be up to 30 times stronger than the plant's star cannabinoid, according to lab analyses conducted on the novel compound. But before you get too excited, scientists admit the way they measured THCP's strength didn't involve testing for intoxication in humans. It's not quite clear yet if it makes for a more intense high.

Rather than the effects of intoxication, the strength the scientists are referring to has to do with the way this compound binds to human CB1 and CB2 receptors, which are found within the body’s endocannabinoid system, or ECS. These receptors are found throughout the body, including in the central and peripheral nervous system and the immune system, where they are involved in a range of cognitive and physiological processes.

According to the report, which was published in the journal Nature, scientists approximated the effects of THCP by examining the binding affinity of the compound to isolated human CB1 and CB2 receptors. Scientists found that the binding affinity of THCP to CB1 is 33 times stronger than that of tetrahydrocannabinol (THC), and 63 times stronger than that of tetrahydrocannabivarin, or THCV. It is also five to 10 times stronger than THC or THCV when binding to CB2 receptors. The study's lead author, Dr. Cinzia Citti, explained it this way to CNN: "This means that these compounds have higher affinity for the receptors in the human body."

Researchers then investigated the effects of this new form of THC in mice. They measured hypolocomotion (slowed movement), analgesia (pain insensitivity), catalepsy (an immobility index measuring stuck-to-the-couch-ness), and body temperature. These measures are used because they are physiological indicators that the body is responding to THC. The mice that were treated with doses of THCP were slower and less sensitive to pain than the control mice. They were also more immobile and had a lower body temperature. This tells us that the mice were responding to THCP in a similar way to THC. The THCP doses that had an effect on the mice were lower than those used in experiments with THC, which supports the scientists’ results with ECS receptors.

Over the course of their research, the scientists were able to identify the structure of THCP, as well as a relative of cannabidiol, or CBD, which they've named CBDP. Something interesting that came up during their investigation was the length of the alkyl side chains in these compared to other cannabinoids. These alkyl side chains are carbon-based, and are the ‘tails' attached to the central multi-ring structure of these molecules. They are known to be a key feature in determining the biological activity of cannabinoids.

While these molecular chains of cannabinoids like THC and CBD have been shown to be five carbons long, THCP stands out as being the longest chain yet in a naturally occurring cannabinoid, with seven carbons. The scientists say this is likely why they have a higher binding affinity to ECS receptors.

What does all this mean? Authors of the report hypothesize that THCP might account for the strong effects associated with certain cultivars, where the amount of THC alone cannot.

“In cannabis varieties where THC is present in very low concentrations, then we can think that the presence of another, more active cannabinoid can explain those effects," said Citti.

This article is available under a Canadian Creative Commons licence.