Cannabis has been used throughout history, but, the way we categorise cannabis – as “sativa,” “indica,” or “hybrid” – may not be the most helpful, especially when it comes to medical use. Scientists are now looking at “terpene profiles” to get a clearer picture of what each type of cannabis can do.
The Old Way: Indica vs. Sativa
Cannabis sativa and Cannabis indica are the names given to the two main types of cannabis plants. Originally distinguished based on their place of origin (Cannabis indica was first used to describe plants found in India), the classification has since been used as a guide to the possible effects of different cannabis products.
Indica strains have often been quoted as being associated with relaxation and sedation, and sativa strains are linked to energy and upliftment. However, this binary classification system is increasingly being challenged. Many modern cannabis strains are hybrids, blurring the lines between indica and sativa characteristics. Moreover, research suggests that the effects of cannabis are influenced by a complex interplay of compounds, not just whether a strain is predominantly indica or sativa.
Cannabis is a complex plant that contains thousands of active compounds, the most prominent of which are cannabinoids. However, cannabis also naturally contains a broad spectrum of terpenes. The authors of a recent analysis argue that the concentration of cannabinoids and terpenes should therefore be considered when categorising cannabis cultivars.
Chemical Fingerprints of Cannabis Chemovars
This analysis aimed to categorise cannabis cultivars by their chemical composition: the term “chemovar” (an abbreviation of “chemical variety”) is used to refer to “a specific variety of a plant whose composition of chemical compounds, such as cannabinoids and terpenes, is unique.”
The researchers examined the chemical fingerprint of medicinal cannabis flowers available on the German market. Their terpene profiles were analysed and correlated with the existing sativa-indica classification. The researchers hypothesised that terpene profiles would provide a better and more reliable categorisation of cannabis strains.
Identified Terpenes and Clustering
A total of 140 cannabis strains were analysed using mass spectrometry. The researchers were able to identify 38 different terpenes at various concentrations. Through analysis, they were able to demonstrate that nine terpenes are responsible for 86% of the variation of the terpene profile: β-myrcene, β-caryophyllene, limonene, linalool, α-humulene, α-pinene, β-pinene, terpinolene, and fenchol accounted for the main characteristics of terpene profiles measured in the samples.
The main findings around terpene groups were as follows:
- There are strong positive linear correlation between limonene and camphene, β-caryophyllene and α-humulene, α- and β-pinene, terpinene and terpinolene, α-phellandrene and terpinolene.
- There are medium-strong negative correlation between guaiol and caryophyllene oxide.
- There are medium-strong positive correlation between THC value and total terpene content.
The correlations make sense from a biochemical point of view. For example, processes already exist within the cannabis plant which can convert β-caryophyllene into α-humulene. Previous research suggests that some terpenes may also protect each other against degradation.
Differences Between Indica, Sativa, and Hybrid
Of the 140 cultivars analysed in this study, 64 were categorised as “hybrids,” 47 as “indica,” and 29 as “sativa”.
- There was no correlation between terpene profile and genetics.
- Comparison of terpene content and genetics showed no differences between indica, sativa, or hybrids.
- There were no significant differences in terpene profiles between the three groups.
Clustering Cannabis Chemovars
The researchers organised the assessed cultivars into six clusters based on their terpene content. Each of the six clusters included sativa, indica, and hybrid cultivars. The researchers propose this clustering as an extension of the existing concept of chemotypes (e.g., THC-dominant, CBD-dominant, balanced).
They note that these clusters may provide advice to healthcare professionals when choosing cultivars with the appropriate characteristics for treating certain indications.
Conclusions
Ongoing research indicates that the conventional classification of cannabis varieties into sativa, indica, and hybrid groups is outdated and often irrelevant – particularly from a medical point of view. The authors of this study suggest the adoption of a new medical-focused classification system based on chemical analyses of cannabinoid and terpene content. They also note that this approach would enable further collection of valid data to prove the efficacy of medical cannabis in various treatment settings.
