By Dr. Daniela Vergara
As we’ve discussed before in multiple other posts, our favorite plant, Cannabis sativa, produces multiple compounds, and these compounds can further turn into other compounds.
Remember when we discussed that CBN is a breakdown product that accumulates as THC ages? After THCA (Delta-9-tetrahydrocannabinolic acid) is decarboxylated into THC (Delta-9-tetrahydrocannabinol), it can degrade further, especially when exposed to oxygen. This exposure causes THC to lose hydrogen atoms and form extra double bonds between carbon atoms, turning into CBN (cannabinol).
Delta-8-THC, which is another slightly different form of THC appears to be another of these breakdown products.
However, terpenes also break down over time, and one fascinating example is hashishene, a terpene that was brought to my attention by our very own leader, David Serrano.
What Is Hashishene?
Hashishene is a terpene found in hashish, the sticky resin made from cannabis flowers. Its scientific name is a bit convoluted (as always…): 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane. Hashishene shows up mostly in hashish and barely anywhere else.
Hashishene forms from another terpene called β-myrcene, which we’ve discussed before. When β-myrcene is exposed to light, especially during the drying and pressing process used to make hashish, it transforms into hashishene. This is why hashishene is mostly found in hashish rather than fresh C. sativa.
Hashishene and light
β-myrcene was experimentally exposed to UV light and hashishene was produced, confirming that this transformation isn’t caused by enzymes in the plant, but by light-driven (photolytic) chemical changes (Marchini et al. 2014). Hashishene also appears in equal parts of its mirror-image forms which are called stereoisomers in chemistry. This supports the idea that it forms randomly through light rather than a biological process.
Found in Hashish
Hashishene has been found in almost all hashish samples, but very little of it shows up in fresh or dried C. sativa flower. Hashishene made up 1.1% to 14.9% of the total volatile compounds in hashish samples (Marchini et al. 2014), and it has also been found in hashish samples from Egypt’s illicit market (Hassan et al. 2023).
Terpenes changing over time
Many terpenes change over time when exposed to different conditions, such as UV light. Each terpene breaks down in its own way and results in different byproducts (Raeber et al. 2025). For example:
- P-cymene was a common result of aging.
- And it seems that other well-known terpenes such as α-pinene may originate from other terpenes.
Impact of post-harvest
I hope we now understand a bit more about why hashish smells different from fresh C. sativa flower. Therefore, does aging means that it changed chemically and the compounds transformed into something else? Could sunlight and time not only dry the plant, but also help form new molecules like hashishene?
Understanding how C. sativa changes over time may be crucial for the industry in general including consumers, producers, and regulators, because it can help:
- Maintain quality and consistency
- Track the source and type of products
- Improve safety for medical and recreational users
Hashishene is more than just a smell and perhaps we should consider it part of hashish’s chemical fingerprint. Cannabis sativa doesn’t stop changing once it’s harvested. Its compounds continue to shift over time as they interact with light and the surrounding environment. Many of these compounds, including both cannabinoids produced by the plant and breakdown products, can also be synthesized in the lab. They are formed in the plant either through enzymatic processes such as THCA or CBDA, or through environmental transformations such as hashishene or Δ8-THC.
On the other hand, there are synthetic cannabinoids like AB-Pinaca (also known as “Spice”) that are not found in the plant at all and can only be made in a lab, but that’s a different story.
If these transformations and synthetic versions exist, what exactly do we mean by ‘natural’? And are these breakdown compounds still considered natural?
References
Hassan, S. S., A. H. Kamel, N. S. Awwad, and A. H. Aboterika. 2023. Characterization of some “hashish” samples in the Egyptian illicit trafficking market using a thermal separation probe and gas chromatography–mass spectrometry. ACS omega 8:25378-25384.
Marchini, M., C. Charvoz, L. Dujourdy, N. Baldovini, and J.-J. Filippi. 2014. Multidimensional analysis of cannabis volatile constituents: Identification of 5, 5-dimethyl-1-vinylbicyclo [2.1. 1] hexane as a volatile marker of hashish, the resin of Cannabis sativa L. Journal of Chromatography A 1370:200-215.
Raeber, J., B. Bajor, M. Poetzsch, and C. Steuer. 2025. Comprehensive analysis of chemical and enantiomeric stability of terpenes in Cannabis sativa L. flowers. Phytochemical Analysis.
