Ah, the great theory of the entourage, or is it rather an overall effect? All the same, terpenesslightly aromatic and often malodorous, can alter the effects of cannabis. And each strain’s set of ingredients produces its own unique experience. Little discussed, however, is the fact that some terpenes are only active by olfactory neurons. This means that these terpenes might not have the same effect in an edible.
When smoked, THCa turns into active D9-THC. From there, it is absorbed into the bloodstream. As many have discovered, active THC (tetrahydrocannabinol) is technically an intoxicant cannabinoid. Included in the experience of many new consumers, THC has a different effect when consumed versus inhaled (smoked or vaped). For the most part, enzymes in the liver convert D8 or D9-THC into another isomer known as 11-hydroxyl-THC.
In comparison, research has slowly advanced and identified a few metabolites produced during the digestion of terpenes in humans. Hiroshima University in Japan studied the metabolic conversion of terpenes in rabbits in 1979. (1) The metabolic processes that plants use to produce terpenes were further characterized in depth in 1995. More recently, some of the sub -metabolic products created when humans digest them. terpenes have also been elucidated. Three terpenes have been studied separately by Lukas Schmidt and Thomas Goen, a pair of researchers in Germany. (2)
Shmidt and Goen first studied 3-carene (CRN) which is a minor terpene found in cannabis. While the data was less conclusive for carene, they detected a metabolite. Small amounts of a carboxylated variant of delta-3-CRN, known as chaminic acid, have been found after human digestion. To add to their findings, the researchers noted other possible metabolites that they did not detect.
- Chaminic acid (CRN-10-COOH)
Alpha-pinene is oxidized in the intestine which produces myrtenol, myrtenic acid and two isomers of verbenol. The latter, at least, may explain some biological effects according to current research.
- Myrtenic acid
- Trans and cis-verbenol
Limonene breaks down into carvone, but then it turns into a few noteworthy compounds during digestion. For example, two isomers of carveol are produced in relatively small amounts by human digestion of r-limonene.
Beyond carveol, more perillic acid is found in human blood (plasma) after consuming the bitter citrus terpene compared to perillyl alcohol. The latter fights tumors according to early research. LMN-8,9-diol is, however, the most abundant metabolite of r-limonene (LMN) in humans, followed by relatively small amounts of a second isomer.
- Perrilic acid
- perillyl alcohol
- Trans and cis-carveol
Does only the nose know linalool?
The nose really knows when it comes to strains you intend to smoke thanks to the terpenes, but the effect doesn’t quite translate to edible. The receptors in our brain and throughout our body receive cannabinoids. While different receptors found in the nasal cavity and gut, for example, respond to at least one terpene. – linalool.
The anti-anxiety properties of linalool might not be as strong when taken orally compared to the smell of the terpene. A specific type of receptor is implicated. Looking at the full picture, however, a multitude of factors alter the effect of linalool depending on the method of consumption. First, the effect depends on olfactory neurons, a type receptor (GCPR) present in the nasal cavity, mouth and intestine.
In one study, linalool did not induce GABA-a, which is the same receptor as benzodiazepine drugs, facilitating relaxation. A later study noted that linalool induced relaxation via GABA-a, but this was dependent on olfactory neurons. Thus, linalool could affect anxiety via edible if enough of the terpene can enter the stomach.
Metabolism and digestion add to this challenge. Linalool converts into three different terpenes as it passes through the esophagus. Beyond that, metabolism subjects linalool to several different alterations. That said, only oxygen atoms (oxygenation) can transform the floral terpene into 8-oxo-linalyl-acetate; the only metabolite that eases anxiety thanks to GABA-a. This is promising because linalool could inhibit seizures and epileptic episodes without affecting mood by a simple natural treatment.
- Several other hydroxylated, carboxylated and oxygenated metabolites
Myrcene and the monoterpene family
Monoterpenes are a family of molecules and become transient under certain conditions. In fact, beta-myrcene is an important precursor molecule for other terpenes like linalool or lemongrass. During digestion, oxidation transforms myrcene into four different molecules, two diols and two hydroxy acids. One diol is known as 10-hydroxylinalool, while one of the acids is 10-carboxylinalool.
- 2-Hydroxy-7-methyl-3-methylene-oct-6-enoic acid
Caryophyllene, edible oil and cannabinoid receptors
Linalool and the other three terpenes mentioned above belong to a group of unique molecules made up of ten carbon atoms, called monoterpenes. While sesquiterpenes consist of 15 carbon atoms; heavier terpenes that are more common in edible. This is because the lighter monoterpenes evaporate during processing (decarboxylation).
β-Caryophyllene is not only the main sesquiterpene found in cannabis, it also directly activates an acute therapeutic action cannabinoid receiver. As it concerns edibleevidence suggests that beta-caryophyllene taken orally will indeed agonize the therapeutic cannabinoid receptor.
Do industries know how terpenes affect edibles?
Terpenes have a big impact on an industry worth billions, driving cannabis. Smells and fragrances drive the cannabis, craft beer and fragrance markets. For this reason, how terpenes affect different human biological receptors has many implications for industries and markets. Growers, processors, and retail must all execute decisions based on terpene profiles. Of course, the scent of a product is still essential, from restaurants to grocery stores and breweries, even if terpenes are less effective when consumed.
Let us know in the comments if you’ve experienced any noticeable effects with terpenes in edible. And which terpenes do you want to know more about?
- Ishida, T., Asakawa, Y., Takemoto, T. and Aratani, T. (1981). Biotransformation of terpenoids in mammals III: Biotransformation of alpha-pinene, beta-pinene, pinane, 3-carene, carane, myrcene and p-cymene in rabbits. Journal of Pharmaceutical Sciences, 70(4), 406–415.
- a.) Schmidt, L., Belov, VN and Göen, T. (2015). Human metabolism of Δ3-carene and renal elimination of Δ3-carene-10-carboxylic acid (chaminic acid) after oral administration. Toxicology Archives, 89(3), 381–392. b.) Schmidt, L., & Göen, T. (2017). Human α-pinene metabolism and metabolite kinetics after oral administration. Toxicology Archives, 91(2), 677–687. VS.) Schmidt, L., & Göen, T. (2017). Metabolism of R-limonene in man and kinetics of metabolites after oral administration. Toxicology Archives, 91(3), 1175-1185. D.) G. Schmidt, L., Lahrz, T., Kraft, M., Göen, T. and Fromme, H. (2015). Monocyclic and bicyclic monoterpenes in German daycare air and human biomonitoring in visiting children, the LUPE 3 study. International environment, 8386–93.
- Milanos, S., Elsharif, SA, Janzen, D., Buettner, A. & Villmann, C. (2017). Linalool metabolic products and GABA modulationA Receivers. Frontiers in chemistry, 546.
- Madyastha, KM, & Srivatsan, V. (1987). Metabolism of beta-myrcene in vivo and in vitro: its effects on rat liver microsomal enzymes. Xenobiotics; the fate of foreign compounds in biological systems, 17(5), 539–549. https://doi.org/10.3109/00498258709043961
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