When you’ve ever taken a whiff of well-preserved, unburned hashish buds, and thought you smelled one thing skunky — or, much less possible, been on the receiving finish of skunk spray and questioned why you reeked of hashish — you would possibly surprise why the 2 scent so comparable.
In different phrases, why does hashish scent a lot like skunk spray? It seems, the smelly culprits in each substances belong to a household of prenylated risky sulfur compounds (VSCs), a subset of risky natural compounds (VOCs), in response to a 2021 examine printed within the journal ACS Omega.
“We suspected that sulfur-containing compounds have been the origins of this aroma, simply primarily based on chemical instinct as chemists,” examine lead writer Iain Oswald, an analytical chemist at Abstrax Tech, an organization that develops fragrant compounds generally known as terpenes in Tustin, California, informed Dwell Science. In spite of everything, “skunks have a bunch of VOCs of their aerosol spray,” so maybe hashish had comparable properties, the crew suspected.
Associated: How does hashish get you excessive?
The sulfurous origins of the plant’s pungency reported within the examine have been maybe anticipated, however the novelty of among the compounds that the crew found weren’t, mentioned Amber Sensible. Sensible is the scientific director and an analytical chemist at Drugs Creek Analytics, a cannabis-testing lab in Fife, Washington, and was not concerned with the examine.
“The skunky scent, you understand, egg scent, if you wish to name it ‘fart scent’ — these are all sulfur compounds, like that is recognized, at the least to chemists,” Sensible informed Dwell Science. “The shocking half was that there is kind of distinctive molecules to hashish.”
These compounds embody VSC6 and VSC7, which Oswald mentioned haven’t earlier than been present in any vegetation.
Hashish has a sophisticated scent profile, with greater than 200 secondary metabolites — small molecules vegetation produce to defend themselves in opposition to predators, resembling bugs, or to draw pollinators — contributing to its distinctive aroma. Terpenes are chief amongst these by way of focus; about six of the fragrant compounds can every be individually chargeable for as much as 50% of the variation in odor between completely different hashish strains, or cultivars, the authors wrote within the examine. For instance, the hashish pressure known as OG Kush will get its signature gasoline-like scent from the terpenes β-myrcene and β-caryophyllene, whereas larger concentrations of terpinolene and D-limonene make the cultivar Jack Herer scent like citrus and wooden.
Whereas the function of terpenes in particular person cultivar profiles has been effectively established, Oswald and his colleagues — three of whom, together with Oswald, have filed a patent associated to their findings — wished to house in on the compounds that give all hashish strains their skunky odor.
VSCs have comparatively advanced buildings, which have made them tough to research. Furthermore, the concentrations of VSCs — that are additionally present in hops and the pungent fruit durian — in Hashish vegetation are minute in contrast with terpenes.
“The quantity truly within the plant may be very low, although it has a really sturdy impact on the odor itself,” Oswald mentioned. “And that is simply because the human nostril may be very delicate to these kinds of compounds, so it does not take so much to go a great distance.”
To grasp the buildings of the sulfurous compounds, Oswald and his colleagues employed a custom-built two-dimensional fuel spectrometry system, mixed with mass spectrometry and sulfur chemiluminescence. These methods allowed them to establish the buildings of every VSC, which numbered seven in complete. Of these seven, the scientists famous that 5 contained a purposeful prenyl group — a function of VSCs which might be present in garlic.
The scientists then had a educated panel of 4 members rank the pungency of the diluted VSCs, together with a set of terpenes and Cannabis flowers, on a scale of zero to 10. The panel famous that VSC3 — which was recognized in a 2001 examine printed in Chemistry — A European Journal as the first compound in “skunked” beer that has been ruined by publicity to ultraviolet gentle — most strongly evoked the skunky aroma of hashish.
“VSC3, by itself, smells like hashish, primarily at a distance,” Oswald mentioned. “The terpenes, by themselves, are very mildly reminiscent.”
This was corroborated when the researchers combined collectively the highest 10 fragrant elements of the Bacio Gelato hashish cultivar however excluded VSC3 — making a scent that the panel famous was evocative of the pressure’s floral scent however not its skunky pungency. Nonetheless, VSC3 does not do all the fragrant heavy lifting by itself.
“There’s this synergistic impact,” Oswald mentioned. “After we combined them collectively, that taste panel mentioned, ‘That is hashish this; that is positively it.'”
Oswald additionally famous that whereas the 2021 paper largely highlighted the numerous contribution of VSC3 to the hashish cultivars’ funky odor, the compounds VSC4 and VSC5 may also play an essential fragrant function.
“VSC3 is by far a very powerful and correlated essentially the most with the cultivars,” Oswald mentioned. “But when we have been to ever uncover a hashish cultivator that did not have VSC3 in any respect however had VSC4 and VSC5, I promise you, all people would say that that smells like hashish.”
Initially printed on Dwell Science.