32) Terpene Content of Cannabis

A Reassessment of Indica and Sativa Lands

Since the 1970s, cannabis consumers have classified strains into two types: Indica and Sativa. However, this division is problematic and sometimes misleading. Although some growers and processors are beginning to reconsider their use of the terms, they are still widely used in both the legal and black markets.

The term “indica” generally refers to cannabis strains that are perceived as relaxing and calming, while the term “sativa” is associated with uplifting and energizing effects. This dichotomy is thought to stem from two distinct genetic lineages with different effects. However, a recent paper published in the journalNature Plants challenges this idea, particularly in the way it is used to describe and sell dried cannabis. The article also reveals that the strain name itself does not accurately indicate the genetic characteristics or chemical composition of the strain. ( link to the article)

Bad Name

The paper, published in October 2021 and titled “Cannabis labeling is associated with genetic variation in terpene synthase genes,” is a collaboration between Dalhousie University, Wageningen University in the Netherlands and Dutch pharmaceutical company Bedrokan International.

The authors first measured the amounts of 40 terpenes in nearly 300 cannabis plant samples using gas chromatography-mass spectrometry (GC-MS). Then, they performed a genomic analysis of the 137 samples from which they were able to extract high-quality DNA. Finally, they examined how well the data obtained by GC-MS and genome analysis matched the classification of the product sample as indica or sativa.

The results show that there are no significant genetic differences between samples classified as indica or sativa. Information about a strain’s breeding history is not as useful as one might think. Similarly, there is no correlation between the content of the cannabinoids tested (THC, CBG, CBD, THCV, CBD, and CBGM) and the classification as indica or sativa. The results are similar for most of the terpenes tested.

Terpenes: The Key

The most important finding of this study is that the “type” of cannabis plant is most closely related to the content of a small number of terpenes. The findings of the paper support the growing movement for more transparent naming practices, which are already gaining traction among users and sellers of cannabis products. As product testing becomes more widespread and sophisticated chemical analyses become available, terpene profiles will become increasingly important for classifying cannabis plants.

In this study, the most abundant substance in samples classified as Sativa was sesquiterpene, which has a woody or tea-like aroma and is not psychoactive. This sesquiterpene provides the expected fruity aroma of sativa strains, while also being suspected of having a calming effect, in contrast to its reputation for an uplifting effect.

On the other hand, products classified as indica strains mainly contained myrcene, a monoterpene with an earthy aroma and sedative effect, as well as guaiol, a sesquiterpene with a piney scent. γ-eudesmol and β-eudesmol, with a woody odor and potential effects on appetite, were also identified. These terpenes are often linked to plants native to Afghanistan, where the cannabis indica plant is thought to have originated.

"This finding shows that the current standard for naming cannabis plants, based on whether they are more sativa or more indica, does not adequately reflect the overall differences between strains from a genomic and metabolic perspective," the paper says. In other words, calling a cannabis plant sativa or indica tells us little about its genetic and chemical makeup.

The authors add that "no practical and reliable classification system, consistent with what is meant by the terms 'sativa' and 'indica', quantifies the content of a small number of terpenes, or might be possible through classification by genetic markers of important fragrances, or both."

In summary, if we want to continue using the terms sativa and indica, it is crucial to rely on specific terpenes or genetic marker analysis. Terpenes play a key role not only in the aroma of cannabis plants, but also in the psychological and physical effects sought by recreational and medical cannabis users.